linux-sg2042/drivers/thermal/intel_powerclamp.c

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/*
* intel_powerclamp.c - package c-state idle injection
*
* Copyright (c) 2012, Intel Corporation.
*
* Authors:
* Arjan van de Ven <arjan@linux.intel.com>
* Jacob Pan <jacob.jun.pan@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*
*
* TODO:
* 1. better handle wakeup from external interrupts, currently a fixed
* compensation is added to clamping duration when excessive amount
* of wakeups are observed during idle time. the reason is that in
* case of external interrupts without need for ack, clamping down
* cpu in non-irq context does not reduce irq. for majority of the
* cases, clamping down cpu does help reduce irq as well, we should
* be able to differenciate the two cases and give a quantitative
* solution for the irqs that we can control. perhaps based on
* get_cpu_iowait_time_us()
*
* 2. synchronization with other hw blocks
*
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/cpu.h>
#include <linux/thermal.h>
#include <linux/slab.h>
#include <linux/tick.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/sched/rt.h>
#include <asm/nmi.h>
#include <asm/msr.h>
#include <asm/mwait.h>
#include <asm/cpu_device_id.h>
#include <asm/idle.h>
#include <asm/hardirq.h>
#define MAX_TARGET_RATIO (50U)
/* For each undisturbed clamping period (no extra wake ups during idle time),
* we increment the confidence counter for the given target ratio.
* CONFIDENCE_OK defines the level where runtime calibration results are
* valid.
*/
#define CONFIDENCE_OK (3)
/* Default idle injection duration, driver adjust sleep time to meet target
* idle ratio. Similar to frequency modulation.
*/
#define DEFAULT_DURATION_JIFFIES (6)
static unsigned int target_mwait;
static struct dentry *debug_dir;
/* user selected target */
static unsigned int set_target_ratio;
static unsigned int current_ratio;
static bool should_skip;
static bool reduce_irq;
static atomic_t idle_wakeup_counter;
static unsigned int control_cpu; /* The cpu assigned to collect stat and update
* control parameters. default to BSP but BSP
* can be offlined.
*/
static bool clamping;
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
static const struct sched_param sparam = {
.sched_priority = MAX_USER_RT_PRIO / 2,
};
struct powerclamp_worker_data {
struct kthread_worker *worker;
struct kthread_work balancing_work;
struct kthread_delayed_work idle_injection_work;
struct timer_list wakeup_timer;
unsigned int cpu;
unsigned int count;
unsigned int guard;
unsigned int window_size_now;
unsigned int target_ratio;
unsigned int duration_jiffies;
bool clamping;
};
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
static struct powerclamp_worker_data * __percpu worker_data;
static struct thermal_cooling_device *cooling_dev;
static unsigned long *cpu_clamping_mask; /* bit map for tracking per cpu
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
* clamping kthread worker
*/
static unsigned int duration;
static unsigned int pkg_cstate_ratio_cur;
static unsigned int window_size;
static int duration_set(const char *arg, const struct kernel_param *kp)
{
int ret = 0;
unsigned long new_duration;
ret = kstrtoul(arg, 10, &new_duration);
if (ret)
goto exit;
if (new_duration > 25 || new_duration < 6) {
pr_err("Out of recommended range %lu, between 6-25ms\n",
new_duration);
ret = -EINVAL;
}
duration = clamp(new_duration, 6ul, 25ul);
smp_mb();
exit:
return ret;
}
static const struct kernel_param_ops duration_ops = {
.set = duration_set,
.get = param_get_int,
};
module_param_cb(duration, &duration_ops, &duration, 0644);
MODULE_PARM_DESC(duration, "forced idle time for each attempt in msec.");
struct powerclamp_calibration_data {
unsigned long confidence; /* used for calibration, basically a counter
* gets incremented each time a clamping
* period is completed without extra wakeups
* once that counter is reached given level,
* compensation is deemed usable.
*/
unsigned long steady_comp; /* steady state compensation used when
* no extra wakeups occurred.
*/
unsigned long dynamic_comp; /* compensate excessive wakeup from idle
* mostly from external interrupts.
*/
};
static struct powerclamp_calibration_data cal_data[MAX_TARGET_RATIO];
static int window_size_set(const char *arg, const struct kernel_param *kp)
{
int ret = 0;
unsigned long new_window_size;
ret = kstrtoul(arg, 10, &new_window_size);
if (ret)
goto exit_win;
if (new_window_size > 10 || new_window_size < 2) {
pr_err("Out of recommended window size %lu, between 2-10\n",
new_window_size);
ret = -EINVAL;
}
window_size = clamp(new_window_size, 2ul, 10ul);
smp_mb();
exit_win:
return ret;
}
static const struct kernel_param_ops window_size_ops = {
.set = window_size_set,
.get = param_get_int,
};
module_param_cb(window_size, &window_size_ops, &window_size, 0644);
MODULE_PARM_DESC(window_size, "sliding window in number of clamping cycles\n"
"\tpowerclamp controls idle ratio within this window. larger\n"
"\twindow size results in slower response time but more smooth\n"
"\tclamping results. default to 2.");
static void find_target_mwait(void)
{
unsigned int eax, ebx, ecx, edx;
unsigned int highest_cstate = 0;
unsigned int highest_subcstate = 0;
int i;
if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
return;
cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
!(ecx & CPUID5_ECX_INTERRUPT_BREAK))
return;
edx >>= MWAIT_SUBSTATE_SIZE;
for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
if (edx & MWAIT_SUBSTATE_MASK) {
highest_cstate = i;
highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
}
}
target_mwait = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
(highest_subcstate - 1);
}
struct pkg_cstate_info {
bool skip;
int msr_index;
int cstate_id;
};
#define PKG_CSTATE_INIT(id) { \
.msr_index = MSR_PKG_C##id##_RESIDENCY, \
.cstate_id = id \
}
static struct pkg_cstate_info pkg_cstates[] = {
PKG_CSTATE_INIT(2),
PKG_CSTATE_INIT(3),
PKG_CSTATE_INIT(6),
PKG_CSTATE_INIT(7),
PKG_CSTATE_INIT(8),
PKG_CSTATE_INIT(9),
PKG_CSTATE_INIT(10),
{NULL},
};
static bool has_pkg_state_counter(void)
{
u64 val;
struct pkg_cstate_info *info = pkg_cstates;
/* check if any one of the counter msrs exists */
while (info->msr_index) {
if (!rdmsrl_safe(info->msr_index, &val))
return true;
info++;
}
return false;
}
static u64 pkg_state_counter(void)
{
u64 val;
u64 count = 0;
struct pkg_cstate_info *info = pkg_cstates;
while (info->msr_index) {
if (!info->skip) {
if (!rdmsrl_safe(info->msr_index, &val))
count += val;
else
info->skip = true;
}
info++;
}
return count;
}
static void noop_timer(unsigned long foo)
{
/* empty... just the fact that we get the interrupt wakes us up */
}
static unsigned int get_compensation(int ratio)
{
unsigned int comp = 0;
/* we only use compensation if all adjacent ones are good */
if (ratio == 1 &&
cal_data[ratio].confidence >= CONFIDENCE_OK &&
cal_data[ratio + 1].confidence >= CONFIDENCE_OK &&
cal_data[ratio + 2].confidence >= CONFIDENCE_OK) {
comp = (cal_data[ratio].steady_comp +
cal_data[ratio + 1].steady_comp +
cal_data[ratio + 2].steady_comp) / 3;
} else if (ratio == MAX_TARGET_RATIO - 1 &&
cal_data[ratio].confidence >= CONFIDENCE_OK &&
cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
cal_data[ratio - 2].confidence >= CONFIDENCE_OK) {
comp = (cal_data[ratio].steady_comp +
cal_data[ratio - 1].steady_comp +
cal_data[ratio - 2].steady_comp) / 3;
} else if (cal_data[ratio].confidence >= CONFIDENCE_OK &&
cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
cal_data[ratio + 1].confidence >= CONFIDENCE_OK) {
comp = (cal_data[ratio].steady_comp +
cal_data[ratio - 1].steady_comp +
cal_data[ratio + 1].steady_comp) / 3;
}
/* REVISIT: simple penalty of double idle injection */
if (reduce_irq)
comp = ratio;
/* do not exceed limit */
if (comp + ratio >= MAX_TARGET_RATIO)
comp = MAX_TARGET_RATIO - ratio - 1;
return comp;
}
static void adjust_compensation(int target_ratio, unsigned int win)
{
int delta;
struct powerclamp_calibration_data *d = &cal_data[target_ratio];
/*
* adjust compensations if confidence level has not been reached or
* there are too many wakeups during the last idle injection period, we
* cannot trust the data for compensation.
*/
if (d->confidence >= CONFIDENCE_OK ||
atomic_read(&idle_wakeup_counter) >
win * num_online_cpus())
return;
delta = set_target_ratio - current_ratio;
/* filter out bad data */
if (delta >= 0 && delta <= (1+target_ratio/10)) {
if (d->steady_comp)
d->steady_comp =
roundup(delta+d->steady_comp, 2)/2;
else
d->steady_comp = delta;
d->confidence++;
}
}
static bool powerclamp_adjust_controls(unsigned int target_ratio,
unsigned int guard, unsigned int win)
{
static u64 msr_last, tsc_last;
u64 msr_now, tsc_now;
u64 val64;
/* check result for the last window */
msr_now = pkg_state_counter();
tsc_now = rdtsc();
/* calculate pkg cstate vs tsc ratio */
if (!msr_last || !tsc_last)
current_ratio = 1;
else if (tsc_now-tsc_last) {
val64 = 100*(msr_now-msr_last);
do_div(val64, (tsc_now-tsc_last));
current_ratio = val64;
}
/* update record */
msr_last = msr_now;
tsc_last = tsc_now;
adjust_compensation(target_ratio, win);
/*
* too many external interrupts, set flag such
* that we can take measure later.
*/
reduce_irq = atomic_read(&idle_wakeup_counter) >=
2 * win * num_online_cpus();
atomic_set(&idle_wakeup_counter, 0);
/* if we are above target+guard, skip */
return set_target_ratio + guard <= current_ratio;
}
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
static void clamp_balancing_func(struct kthread_work *work)
{
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
struct powerclamp_worker_data *w_data;
int sleeptime;
unsigned long target_jiffies;
unsigned int compensated_ratio;
int interval; /* jiffies to sleep for each attempt */
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
w_data = container_of(work, struct powerclamp_worker_data,
balancing_work);
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
/*
* make sure user selected ratio does not take effect until
* the next round. adjust target_ratio if user has changed
* target such that we can converge quickly.
*/
w_data->target_ratio = READ_ONCE(set_target_ratio);
w_data->guard = 1 + w_data->target_ratio / 20;
w_data->window_size_now = window_size;
w_data->duration_jiffies = msecs_to_jiffies(duration);
w_data->count++;
/*
* systems may have different ability to enter package level
* c-states, thus we need to compensate the injected idle ratio
* to achieve the actual target reported by the HW.
*/
compensated_ratio = w_data->target_ratio +
get_compensation(w_data->target_ratio);
if (compensated_ratio <= 0)
compensated_ratio = 1;
interval = w_data->duration_jiffies * 100 / compensated_ratio;
/* align idle time */
target_jiffies = roundup(jiffies, interval);
sleeptime = target_jiffies - jiffies;
if (sleeptime <= 0)
sleeptime = 1;
if (clamping && w_data->clamping && cpu_online(w_data->cpu))
kthread_queue_delayed_work(w_data->worker,
&w_data->idle_injection_work,
sleeptime);
}
static void clamp_idle_injection_func(struct kthread_work *work)
{
struct powerclamp_worker_data *w_data;
unsigned long target_jiffies;
w_data = container_of(work, struct powerclamp_worker_data,
idle_injection_work.work);
/*
* only elected controlling cpu can collect stats and update
* control parameters.
*/
if (w_data->cpu == control_cpu &&
!(w_data->count % w_data->window_size_now)) {
should_skip =
powerclamp_adjust_controls(w_data->target_ratio,
w_data->guard,
w_data->window_size_now);
smp_mb();
}
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
if (should_skip)
goto balance;
target_jiffies = jiffies + w_data->duration_jiffies;
mod_timer(&w_data->wakeup_timer, target_jiffies);
if (unlikely(local_softirq_pending()))
goto balance;
/*
* stop tick sched during idle time, interrupts are still
* allowed. thus jiffies are updated properly.
*/
preempt_disable();
/* mwait until target jiffies is reached */
while (time_before(jiffies, target_jiffies)) {
unsigned long ecx = 1;
unsigned long eax = target_mwait;
/*
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
* REVISIT: may call enter_idle() to notify drivers who
* can save power during cpu idle. same for exit_idle()
*/
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
local_touch_nmi();
stop_critical_timings();
mwait_idle_with_hints(eax, ecx);
start_critical_timings();
atomic_inc(&idle_wakeup_counter);
}
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
preempt_enable();
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
balance:
if (clamping && w_data->clamping && cpu_online(w_data->cpu))
kthread_queue_work(w_data->worker, &w_data->balancing_work);
}
/*
* 1 HZ polling while clamping is active, useful for userspace
* to monitor actual idle ratio.
*/
static void poll_pkg_cstate(struct work_struct *dummy);
static DECLARE_DELAYED_WORK(poll_pkg_cstate_work, poll_pkg_cstate);
static void poll_pkg_cstate(struct work_struct *dummy)
{
static u64 msr_last;
static u64 tsc_last;
static unsigned long jiffies_last;
u64 msr_now;
unsigned long jiffies_now;
u64 tsc_now;
u64 val64;
msr_now = pkg_state_counter();
tsc_now = rdtsc();
jiffies_now = jiffies;
/* calculate pkg cstate vs tsc ratio */
if (!msr_last || !tsc_last)
pkg_cstate_ratio_cur = 1;
else {
if (tsc_now - tsc_last) {
val64 = 100 * (msr_now - msr_last);
do_div(val64, (tsc_now - tsc_last));
pkg_cstate_ratio_cur = val64;
}
}
/* update record */
msr_last = msr_now;
jiffies_last = jiffies_now;
tsc_last = tsc_now;
if (true == clamping)
schedule_delayed_work(&poll_pkg_cstate_work, HZ);
}
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
static void start_power_clamp_worker(unsigned long cpu)
{
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
struct powerclamp_worker_data *w_data = per_cpu_ptr(worker_data, cpu);
struct kthread_worker *worker;
worker = kthread_create_worker_on_cpu(cpu, KTW_FREEZABLE,
"kidle_inject/%ld", cpu);
if (IS_ERR(worker))
return;
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
w_data->worker = worker;
w_data->count = 0;
w_data->cpu = cpu;
w_data->clamping = true;
set_bit(cpu, cpu_clamping_mask);
setup_timer(&w_data->wakeup_timer, noop_timer, 0);
sched_setscheduler(worker->task, SCHED_FIFO, &sparam);
kthread_init_work(&w_data->balancing_work, clamp_balancing_func);
kthread_init_delayed_work(&w_data->idle_injection_work,
clamp_idle_injection_func);
kthread_queue_work(w_data->worker, &w_data->balancing_work);
}
static void stop_power_clamp_worker(unsigned long cpu)
{
struct powerclamp_worker_data *w_data = per_cpu_ptr(worker_data, cpu);
if (!w_data->worker)
return;
w_data->clamping = false;
/*
* Make sure that all works that get queued after this point see
* the clamping disabled. The counter part is not needed because
* there is an implicit memory barrier when the queued work
* is proceed.
*/
smp_wmb();
kthread_cancel_work_sync(&w_data->balancing_work);
kthread_cancel_delayed_work_sync(&w_data->idle_injection_work);
/*
* The balancing work still might be queued here because
* the handling of the "clapming" variable, cancel, and queue
* operations are not synchronized via a lock. But it is not
* a big deal. The balancing work is fast and destroy kthread
* will wait for it.
*/
del_timer_sync(&w_data->wakeup_timer);
clear_bit(w_data->cpu, cpu_clamping_mask);
kthread_destroy_worker(w_data->worker);
w_data->worker = NULL;
}
static int start_power_clamp(void)
{
unsigned long cpu;
set_target_ratio = clamp(set_target_ratio, 0U, MAX_TARGET_RATIO - 1);
/* prevent cpu hotplug */
get_online_cpus();
/* prefer BSP */
control_cpu = 0;
if (!cpu_online(control_cpu))
control_cpu = smp_processor_id();
clamping = true;
schedule_delayed_work(&poll_pkg_cstate_work, 0);
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
/* start one kthread worker per online cpu */
for_each_online_cpu(cpu) {
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
start_power_clamp_worker(cpu);
}
put_online_cpus();
return 0;
}
static void end_power_clamp(void)
{
int i;
/*
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
* Block requeuing in all the kthread workers. They will flush and
* stop faster.
*/
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
clamping = false;
if (bitmap_weight(cpu_clamping_mask, num_possible_cpus())) {
for_each_set_bit(i, cpu_clamping_mask, num_possible_cpus()) {
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
pr_debug("clamping worker for cpu %d alive, destroy\n",
i);
stop_power_clamp_worker(i);
}
}
}
static int powerclamp_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
unsigned long cpu = (unsigned long)hcpu;
if (false == clamping)
goto exit_ok;
switch (action) {
case CPU_ONLINE:
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
start_power_clamp_worker(cpu);
/* prefer BSP as controlling CPU */
if (cpu == 0) {
control_cpu = 0;
smp_mb();
}
break;
case CPU_DEAD:
if (test_bit(cpu, cpu_clamping_mask)) {
pr_err("cpu %lu dead but powerclamping thread is not\n",
cpu);
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
stop_power_clamp_worker(cpu);
}
if (cpu == control_cpu) {
control_cpu = smp_processor_id();
smp_mb();
}
}
exit_ok:
return NOTIFY_OK;
}
static struct notifier_block powerclamp_cpu_notifier = {
.notifier_call = powerclamp_cpu_callback,
};
static int powerclamp_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
*state = MAX_TARGET_RATIO;
return 0;
}
static int powerclamp_get_cur_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
if (true == clamping)
*state = pkg_cstate_ratio_cur;
else
/* to save power, do not poll idle ratio while not clamping */
*state = -1; /* indicates invalid state */
return 0;
}
static int powerclamp_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long new_target_ratio)
{
int ret = 0;
new_target_ratio = clamp(new_target_ratio, 0UL,
(unsigned long) (MAX_TARGET_RATIO-1));
if (set_target_ratio == 0 && new_target_ratio > 0) {
pr_info("Start idle injection to reduce power\n");
set_target_ratio = new_target_ratio;
ret = start_power_clamp();
goto exit_set;
} else if (set_target_ratio > 0 && new_target_ratio == 0) {
pr_info("Stop forced idle injection\n");
end_power_clamp();
thermal/powerclamp: Prevent division by zero when counting interval I have got a zero division error when disabling the forced idle injection from the intel powerclamp. I did echo 0 >/sys/class/thermal/cooling_device48/cur_state and got [ 986.072632] divide error: 0000 [#1] PREEMPT SMP [ 986.078989] Modules linked in: [ 986.083618] CPU: 17 PID: 24967 Comm: kidle_inject/17 Not tainted 4.7.0-1-default+ #3055 [ 986.093781] Hardware name: Intel Corporation S2600CP/S2600CP, BIOS RMLSDP.86I.R3.27.D685.1305151734 05/15/2013 [ 986.106227] task: ffff880430e1c080 task.stack: ffff880427ef0000 [ 986.114122] RIP: 0010:[<ffffffff81794859>] [<ffffffff81794859>] clamp_thread+0x1d9/0x600 [ 986.124609] RSP: 0018:ffff880427ef3e20 EFLAGS: 00010246 [ 986.131860] RAX: 0000000000000258 RBX: 0000000000000006 RCX: 0000000000000001 [ 986.141179] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000018 [ 986.150478] RBP: ffff880427ef3ec8 R08: ffff880427ef0000 R09: 0000000000000002 [ 986.159779] R10: 0000000000003df2 R11: 0000000000000018 R12: 0000000000000002 [ 986.169089] R13: 0000000000000000 R14: ffff880427ef0000 R15: ffff880427ef0000 [ 986.178388] FS: 0000000000000000(0000) GS:ffff880435940000(0000) knlGS:0000000000000000 [ 986.188785] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 986.196559] CR2: 00007f1d0caf0000 CR3: 0000000002006000 CR4: 00000000001406e0 [ 986.205909] Stack: [ 986.209524] ffff8802be897b00 ffff880430e1c080 0000000000000011 0000006a35959780 [ 986.219236] 0000000000000011 ffff880427ef0008 0000000000000000 ffff8804359503d0 [ 986.228966] 0000000100029d93 ffffffff81794140 0000000000000000 ffffffff05000011 [ 986.238686] Call Trace: [ 986.242825] [<ffffffff81794140>] ? pkg_state_counter+0x80/0x80 [ 986.250866] [<ffffffff81794680>] ? powerclamp_set_cur_state+0x180/0x180 [ 986.259797] [<ffffffff8111d1a9>] kthread+0xc9/0xe0 [ 986.266682] [<ffffffff8193d69f>] ret_from_fork+0x1f/0x40 [ 986.274142] [<ffffffff8111d0e0>] ? kthread_create_on_node+0x180/0x180 [ 986.282869] Code: d1 ea 48 89 d6 80 3d 6a d0 d4 00 00 ba 64 00 00 00 89 d8 41 0f 45 f5 0f af c2 42 8d 14 2e be 31 00 00 00 83 fa 31 0f 42 f2 31 d2 <f7> f6 48 8b 15 9e 07 87 00 48 8b 3d 97 07 87 00 48 63 f0 83 e8 [ 986.307806] RIP [<ffffffff81794859>] clamp_thread+0x1d9/0x600 [ 986.315871] RSP <ffff880427ef3e20> RIP points to the following lines: compensation = get_compensation(target_ratio); interval = duration_jiffies*100/(target_ratio+compensation); A solution would be to switch the following two commands in powerclamp_set_cur_state(): set_target_ratio = 0; end_power_clamp(); But I think that the zero division might happen also when target_ratio is non-zero because the compensation might be negative. Therefore we also check the sum of target_ratio and compensation explicitly. Also the compensated_ratio variable is always set. Therefore there is no need to initialize it. Signed-off-by: Petr Mladek <pmladek@suse.com> Acked-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2016-08-05 21:20:41 +08:00
set_target_ratio = 0;
} else /* adjust currently running */ {
set_target_ratio = new_target_ratio;
/* make new set_target_ratio visible to other cpus */
smp_mb();
}
exit_set:
return ret;
}
/* bind to generic thermal layer as cooling device*/
static struct thermal_cooling_device_ops powerclamp_cooling_ops = {
.get_max_state = powerclamp_get_max_state,
.get_cur_state = powerclamp_get_cur_state,
.set_cur_state = powerclamp_set_cur_state,
};
static const struct x86_cpu_id intel_powerclamp_ids[] __initconst = {
{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_MWAIT },
{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_ARAT },
{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_NONSTOP_TSC },
{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_CONSTANT_TSC},
{}
};
MODULE_DEVICE_TABLE(x86cpu, intel_powerclamp_ids);
static int __init powerclamp_probe(void)
{
if (!x86_match_cpu(intel_powerclamp_ids)) {
pr_err("Intel powerclamp does not run on family %d model %d\n",
boot_cpu_data.x86, boot_cpu_data.x86_model);
return -ENODEV;
}
/* The goal for idle time alignment is to achieve package cstate. */
if (!has_pkg_state_counter()) {
pr_info("No package C-state available");
return -ENODEV;
}
/* find the deepest mwait value */
find_target_mwait();
return 0;
}
static int powerclamp_debug_show(struct seq_file *m, void *unused)
{
int i = 0;
seq_printf(m, "controlling cpu: %d\n", control_cpu);
seq_printf(m, "pct confidence steady dynamic (compensation)\n");
for (i = 0; i < MAX_TARGET_RATIO; i++) {
seq_printf(m, "%d\t%lu\t%lu\t%lu\n",
i,
cal_data[i].confidence,
cal_data[i].steady_comp,
cal_data[i].dynamic_comp);
}
return 0;
}
static int powerclamp_debug_open(struct inode *inode,
struct file *file)
{
return single_open(file, powerclamp_debug_show, inode->i_private);
}
static const struct file_operations powerclamp_debug_fops = {
.open = powerclamp_debug_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.owner = THIS_MODULE,
};
static inline void powerclamp_create_debug_files(void)
{
debug_dir = debugfs_create_dir("intel_powerclamp", NULL);
if (!debug_dir)
return;
if (!debugfs_create_file("powerclamp_calib", S_IRUGO, debug_dir,
cal_data, &powerclamp_debug_fops))
goto file_error;
return;
file_error:
debugfs_remove_recursive(debug_dir);
}
static int __init powerclamp_init(void)
{
int retval;
int bitmap_size;
bitmap_size = BITS_TO_LONGS(num_possible_cpus()) * sizeof(long);
cpu_clamping_mask = kzalloc(bitmap_size, GFP_KERNEL);
if (!cpu_clamping_mask)
return -ENOMEM;
/* probe cpu features and ids here */
retval = powerclamp_probe();
if (retval)
goto exit_free;
/* set default limit, maybe adjusted during runtime based on feedback */
window_size = 2;
register_hotcpu_notifier(&powerclamp_cpu_notifier);
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
worker_data = alloc_percpu(struct powerclamp_worker_data);
if (!worker_data) {
retval = -ENOMEM;
goto exit_unregister;
}
cooling_dev = thermal_cooling_device_register("intel_powerclamp", NULL,
&powerclamp_cooling_ops);
if (IS_ERR(cooling_dev)) {
retval = -ENODEV;
goto exit_free_thread;
}
if (!duration)
duration = jiffies_to_msecs(DEFAULT_DURATION_JIFFIES);
powerclamp_create_debug_files();
return 0;
exit_free_thread:
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
free_percpu(worker_data);
exit_unregister:
unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
exit_free:
kfree(cpu_clamping_mask);
return retval;
}
module_init(powerclamp_init);
static void __exit powerclamp_exit(void)
{
unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
end_power_clamp();
thermal/intel_powerclamp: Convert the kthread to kthread worker API Kthreads are currently implemented as an infinite loop. Each has its own variant of checks for terminating, freezing, awakening. In many cases it is unclear to say in which state it is and sometimes it is done a wrong way. The plan is to convert kthreads into kthread_worker or workqueues API. It allows to split the functionality into separate operations. It helps to make a better structure. Also it defines a clean state where no locks are taken, IRQs blocked, the kthread might sleep or even be safely migrated. The kthread worker API is useful when we want to have a dedicated single thread for the work. It helps to make sure that it is available when needed. Also it allows a better control, e.g. define a scheduling priority. This patch converts the intel powerclamp kthreads into the kthread worker because they need to have a good control over the assigned CPUs. IMHO, the most natural way is to split one cycle into two works. First one does some balancing and let the CPU work normal way for some time. The second work checks what the CPU has done in the meantime and put it into C-state to reach the required idle time ratio. The delay between the two works is achieved by the delayed kthread work. The two works have to share some data that used to be local variables of the single kthread function. This is achieved by the new per-CPU struct kthread_worker_data. It might look as a complication. On the other hand, the long original kthread function was not nice either. The patch tries to avoid extra init and cleanup works. All the actions might be done outside the thread. They are moved to the functions that create or destroy the worker. Especially, I checked that the timers are assigned to the right CPU. The two works are queuing each other. It makes it a bit tricky to break it when we want to stop the worker. We use the global and per-worker "clamping" variables to make sure that the re-queuing eventually stops. We also cancel the works to make it faster. Note that the canceling is not reliable because the handling of the two variables and queuing is not synchronized via a lock. But it is not a big deal because it is just an optimization. The job is stopped faster than before in most cases. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-29 05:44:50 +08:00
free_percpu(worker_data);
thermal_cooling_device_unregister(cooling_dev);
kfree(cpu_clamping_mask);
cancel_delayed_work_sync(&poll_pkg_cstate_work);
debugfs_remove_recursive(debug_dir);
}
module_exit(powerclamp_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
MODULE_DESCRIPTION("Package Level C-state Idle Injection for Intel CPUs");