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cpufreq: Remove unused APERF/MPERF support 

The target frequency calculation method in the ondemand governor has
changed and it is now independent of the measured average frequency.
Consequently, the APERF/MPERF support in cpufreq is not used any
more, so drop it.

[rjw: Changelog]
Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Stratos Karafotis 2013-06-05 19:01:42 +03:00 committed by Rafael J. Wysocki
parent dfa5bb6225
commit 61c63e5ed3
5 changed files with 1 additions and 95 deletions
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29
arch/x86/include/asm/processor.h
View File

@ -942,35 +942,6 @@ extern int set_tsc_mode(unsigned int val);
extern u16 amd_get_nb_id(int cpu);
struct aperfmperf {
u64 aperf, mperf;
};
static inline void get_aperfmperf(struct aperfmperf *am)
{
WARN_ON_ONCE(!boot_cpu_has(X86_FEATURE_APERFMPERF));
rdmsrl(MSR_IA32_APERF, am->aperf);
rdmsrl(MSR_IA32_MPERF, am->mperf);
}
#define APERFMPERF_SHIFT 10
static inline
unsigned long calc_aperfmperf_ratio(struct aperfmperf *old,
struct aperfmperf *new)
{
u64 aperf = new->aperf - old->aperf;
u64 mperf = new->mperf - old->mperf;
unsigned long ratio = aperf;
mperf >>= APERFMPERF_SHIFT;
if (mperf)
ratio = div64_u64(aperf, mperf);
return ratio;
}
extern unsigned long arch_align_stack(unsigned long sp);
extern void free_init_pages(char *what, unsigned long begin, unsigned long end);

2
drivers/cpufreq/Makefile
View File

@ -23,7 +23,7 @@ obj-$(CONFIG_GENERIC_CPUFREQ_CPU0) += cpufreq-cpu0.o
# powernow-k8 can load then. ACPI is preferred to all other hardware-specific drivers.
# speedstep-* is preferred over p4-clockmod.
obj-$(CONFIG_X86_ACPI_CPUFREQ) += acpi-cpufreq.o mperf.o
obj-$(CONFIG_X86_ACPI_CPUFREQ) += acpi-cpufreq.o
obj-$(CONFIG_X86_POWERNOW_K8) += powernow-k8.o
obj-$(CONFIG_X86_PCC_CPUFREQ) += pcc-cpufreq.o
obj-$(CONFIG_X86_POWERNOW_K6) += powernow-k6.o

5
drivers/cpufreq/acpi-cpufreq.c
View File

@ -45,7 +45,6 @@
#include <asm/msr.h>
#include <asm/processor.h>
#include <asm/cpufeature.h>
#include "mperf.h"
MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
MODULE_DESCRIPTION("ACPI Processor P-States Driver");
@ -861,10 +860,6 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
/* notify BIOS that we exist */
acpi_processor_notify_smm(THIS_MODULE);
/* Check for APERF/MPERF support in hardware */
if (boot_cpu_has(X86_FEATURE_APERFMPERF))
acpi_cpufreq_driver.getavg = cpufreq_get_measured_perf;
pr_debug("CPU%u - ACPI performance management activated.\n", cpu);
for (i = 0; i < perf->state_count; i++)
pr_debug(" %cP%d: %d MHz, %d mW, %d uS\n",

51
drivers/cpufreq/mperf.c
View File

@ -1,51 +0,0 @@
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include "mperf.h"
static DEFINE_PER_CPU(struct aperfmperf, acfreq_old_perf);
/* Called via smp_call_function_single(), on the target CPU */
static void read_measured_perf_ctrs(void *_cur)
{
struct aperfmperf *am = _cur;
get_aperfmperf(am);
}
/*
* Return the measured active (C0) frequency on this CPU since last call
* to this function.
* Input: cpu number
* Return: Average CPU frequency in terms of max frequency (zero on error)
*
* We use IA32_MPERF and IA32_APERF MSRs to get the measured performance
* over a period of time, while CPU is in C0 state.
* IA32_MPERF counts at the rate of max advertised frequency
* IA32_APERF counts at the rate of actual CPU frequency
* Only IA32_APERF/IA32_MPERF ratio is architecturally defined and
* no meaning should be associated with absolute values of these MSRs.
*/
unsigned int cpufreq_get_measured_perf(struct cpufreq_policy *policy,
unsigned int cpu)
{
struct aperfmperf perf;
unsigned long ratio;
unsigned int retval;
if (smp_call_function_single(cpu, read_measured_perf_ctrs, &perf, 1))
return 0;
ratio = calc_aperfmperf_ratio(&per_cpu(acfreq_old_perf, cpu), &perf);
per_cpu(acfreq_old_perf, cpu) = perf;
retval = (policy->cpuinfo.max_freq * ratio) >> APERFMPERF_SHIFT;
return retval;
}
EXPORT_SYMBOL_GPL(cpufreq_get_measured_perf);
MODULE_LICENSE("GPL");

9
drivers/cpufreq/mperf.h
View File

@ -1,9 +0,0 @@
/*
* (c) 2010 Advanced Micro Devices, Inc.
* Your use of this code is subject to the terms and conditions of the
* GNU general public license version 2. See "COPYING" or
* http://www.gnu.org/licenses/gpl.html
*/
unsigned int cpufreq_get_measured_perf(struct cpufreq_policy *policy,
unsigned int cpu);