Commit Graph

224 Commits

Author SHA1 Message Date
Viresh Kumar 2f0531869f cpufreq: Remove unused flag CPUFREQ_PM_NO_WARN
This flag is set by one of the drivers but it isn't used in the code
otherwise. Remove the unused flag and update the driver.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-02-04 19:25:47 +01:00
Viresh Kumar 5ae4a4b45d cpufreq: Remove CPUFREQ_STICKY flag
During cpufreq driver's registration, if the ->init() callback for all
the CPUs fail then there is not much point in keeping the driver around
as it will only account for more of unnecessary noise, for example
cpufreq core will try to suspend/resume the driver which never got
registered properly.

The removal of such a driver is avoided if the driver carries the
CPUFREQ_STICKY flag. This was added way back [1] in 2004 and perhaps no
one should ever need it now. A lot of drivers do set this flag, probably
because they just copied it from other drivers.

This was added earlier for some platforms [2] because their cpufreq
drivers were getting registered before the CPUs were registered with
subsys framework. And hence they used to fail.

The same isn't true anymore though. The current code flow in the kernel
is:

start_kernel()
-> kernel_init()
   -> kernel_init_freeable()
      -> do_basic_setup()
         -> driver_init()
            -> cpu_dev_init()
               -> subsys_system_register() //For CPUs

         -> do_initcalls()
            -> cpufreq_register_driver()

Clearly, the CPUs will always get registered with subsys framework
before any cpufreq driver can get probed. Remove the flag and update the
relevant drivers.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/include/linux/cpufreq.h?id=7cc9f0d9a1ab04cedc60d64fd8dcf7df224a3b4d # [1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/arch/arm/mach-sa1100/cpu-sa1100.c?id=f59d3bbe35f6268d729f51be82af8325d62f20f5 # [2]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-02-04 19:23:20 +01:00
Rafael J. Wysocki ee2cc4276b cpufreq: Add special-purpose fast-switching callback for drivers
First off, some cpufreq drivers (eg. intel_pstate) can pass hints
beyond the current target frequency to the hardware and there are no
provisions for doing that in the cpufreq framework.  In particular,
today the driver has to assume that it should not allow the frequency
to fall below the one requested by the governor (or the required
capacity may not be provided) which may not be the case and which may
lead to excessive energy usage in some scenarios.

Second, the hints passed by these drivers to the hardware need not be
in terms of the frequency, so representing the utilization numbers
coming from the scheduler as frequency before passing them to those
drivers is not really useful.

Address the two points above by adding a special-purpose replacement
for the ->fast_switch callback, called ->adjust_perf, allowing the
governor to pass abstract performance level (rather than frequency)
values for the minimum (required) and target (desired) performance
along with the CPU capacity to compare them to.

Also update the schedutil governor to use the new callback instead
of ->fast_switch if present and if the utilization mertics are
frequency-invariant (that is requisite for the direct mapping
between the utilization and the CPU performance levels to be a
reasonable approximation).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-12-15 19:24:18 +01:00
Rafael J. Wysocki ef7ece9a9b Merge back cpufreq updates for v5.11. 2020-11-16 13:20:31 +01:00
Rafael J. Wysocki ea9364bbad cpufreq: Add strict_target to struct cpufreq_policy
Add a new field to be set when the CPUFREQ_GOV_STRICT_TARGET flag is
set for the current governor to struct cpufreq_policy, so that the
drivers needing to check CPUFREQ_GOV_STRICT_TARGET do not have to
access the governor object during every frequency transition.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-11-10 18:31:17 +01:00
Rafael J. Wysocki 218f668701 cpufreq: Introduce CPUFREQ_GOV_STRICT_TARGET
Introduce a new governor flag, CPUFREQ_GOV_STRICT_TARGET, for the
governors that want the target frequency to be set exactly to the
given value without leaving any room for adjustments on the hardware
side and set this flag for the powersave and performance governors.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-11-10 18:31:17 +01:00
Rafael J. Wysocki 9a2a9ebc0a cpufreq: Introduce governor flags
A new cpufreq governor flag will be added subsequently, so replace
the bool dynamic_switching fleid in struct cpufreq_governor with a
flags field and introduce CPUFREQ_GOV_DYNAMIC_SWITCHING to set for
the "dynamic switching" governors instead of it.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-11-10 18:31:17 +01:00
Rafael J. Wysocki 56a7ff75cd cpufreq: Drop restore_freq from struct cpufreq_policy
The restore_freq field in struct cpufreq_policy is only used by
__target_index() in one place and a local variable in that function
may as well be used instead of it, so drop it and modify
__target_index() accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-11-02 18:32:39 +01:00
Rafael J. Wysocki a62f68f5ca cpufreq: Introduce cpufreq_driver_test_flags()
Add a helper function to test the flags of the cpufreq driver in use
againt a given flags mask.

In particular, this will be needed to test the
CPUFREQ_NEED_UPDATE_LIMITS cpufreq driver flag in the schedutil
governor.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-10-29 14:07:30 +01:00
Rafael J. Wysocki 1c534352f4 cpufreq: Introduce CPUFREQ_NEED_UPDATE_LIMITS driver flag
Generally, a cpufreq driver may need to update some internal upper
and lower frequency boundaries on policy max and min changes,
respectively, but currently this does not work if the target
frequency does not change along with the policy limit.

Namely, if the target frequency does not change along with the
policy min or max, the "target_freq == policy->cur" check in
__cpufreq_driver_target() prevents driver callbacks from being
invoked and they do not even have a chance to update the
corresponding internal boundary.

This particularly affects the "powersave" and "performance"
governors that always set the target frequency to one of the
policy limits and it never changes when the other limit is updated.

To allow cpufreq the drivers needing to update internal frequency
boundaries on policy limits changes to avoid this issue, introduce
a new driver flag, CPUFREQ_NEED_UPDATE_LIMITS, that (when set) will
neutralize the check mentioned above.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-10-27 18:47:40 +01:00
Ionela Voinescu a20b7053b5 cpufreq,arm,arm64: restructure definitions of arch_set_freq_scale()
Compared to other arch_* functions, arch_set_freq_scale() has an atypical
weak definition that can be replaced by a strong architecture specific
implementation.

The more typical support for architectural functions involves defining
an empty stub in a header file if the symbol is not already defined in
architecture code. Some examples involve:
 - #define arch_scale_freq_capacity	topology_get_freq_scale
 - #define arch_scale_freq_invariant	topology_scale_freq_invariant
 - #define arch_scale_cpu_capacity	topology_get_cpu_scale
 - #define arch_update_cpu_topology	topology_update_cpu_topology
 - #define arch_scale_thermal_pressure	topology_get_thermal_pressure
 - #define arch_set_thermal_pressure	topology_set_thermal_pressure

Bring arch_set_freq_scale() in line with these functions by renaming it to
topology_set_freq_scale() in the arch topology driver, and by defining the
arch_set_freq_scale symbol to point to the new function for arm and arm64.

While there are other users of the arch_topology driver, this patch defines
arch_set_freq_scale for arm and arm64 only, due to their existing
definitions of arch_scale_freq_capacity. This is the getter function of the
frequency invariance scale factor and without a getter function, the
setter function - arch_set_freq_scale() has not purpose.

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com> (BL_SWITCHER and topology parts)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-10-08 17:17:27 +02:00
Valentin Schneider ecddc3a0d5 arch_topology, cpufreq: constify arch_* cpumasks
The passed cpumask arguments to arch_set_freq_scale() and
arch_freq_counters_available() are only iterated over, so reflect this
in the prototype. This also allows to pass system cpumasks like
cpu_online_mask without getting a warning.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-09-18 19:11:04 +02:00
Ionela Voinescu 874f635310 cpufreq: report whether cpufreq supports Frequency Invariance (FI)
Now that the update of the FI scale factor is done in cpufreq core for
selected functions - target(), target_index() and fast_switch(),
we can provide feedback to the task scheduler and architecture code
on whether cpufreq supports FI.

For this purpose provide an external function to expose whether the
cpufreq drivers support FI, by using a static key.

The logic behind the enablement of cpufreq-based invariance is as
follows:
 - cpufreq-based invariance is disabled by default
 - cpufreq-based invariance is enabled if any of the callbacks
   above is implemented while the unsupported setpolicy() is not

The cpufreq_supports_freq_invariance() function only returns whether
cpufreq is instrumented with the arch_set_freq_scale() calls that
result in support for frequency invariance. Due to the lack of knowledge
on whether the implementation of arch_set_freq_scale() actually results
in the setting of a scale factor based on cpufreq information, it is up
to the architecture code to ensure the setting and provision of the
scale factor to the scheduler.

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-09-18 19:10:56 +02:00
Viresh Kumar 30b8e6b22f cpufreq: Use WARN_ON_ONCE() for invalid relation
The relation can't be invalid here, so if it turns out to be invalid,
just WARN_ON_ONCE() and return 0.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-08-27 12:51:25 +02:00
Rafael J. Wysocki f6ebbcf08f cpufreq: intel_pstate: Implement passive mode with HWP enabled
Allow intel_pstate to work in the passive mode with HWP enabled and
make it set the HWP minimum performance limit (HWP floor) to the
P-state value given by the target frequency supplied by the cpufreq
governor, so as to prevent the HWP algorithm and the CPU scheduler
from working against each other, at least when the schedutil governor
is in use, and update the intel_pstate documentation accordingly.

Among other things, this allows utilization clamps to be taken
into account, at least to a certain extent, when intel_pstate is
in use and makes it more likely that sufficient capacity for
deadline tasks will be provided.

After this change, the resulting behavior of an HWP system with
intel_pstate in the passive mode should be close to the behavior
of the analogous non-HWP system with intel_pstate in the passive
mode, except that the HWP algorithm is generally allowed to make the
CPU run at a frequency above the floor P-state set by intel_pstate in
the entire available range of P-states, while without HWP a CPU can
run in a P-state above the requested one if the latter falls into the
range of turbo P-states (referred to as the turbo range) or if the
P-states of all CPUs in one package are coordinated with each other
at the hardware level.

[Note that in principle the HWP floor may not be taken into account
 by the processor if it falls into the turbo range, in which case the
 processor has a license to choose any P-state, either below or above
 the HWP floor, just like a non-HWP processor in the case when the
 target P-state falls into the turbo range.]

With this change applied, intel_pstate in the passive mode assumes
complete control over the HWP request MSR and concurrent changes of
that MSR (eg. via the direct MSR access interface) are overridden by
it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
2020-08-11 17:29:45 +02:00
Rafael J. Wysocki 9ac1fb156a Merge branch 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm
Pull ARM cpufreq driver changes for v5.9-rc1 from Viresh Kumar:

"Here are the details:

- Adaptive voltage scaling (AVS) support and minor cleanups for
  brcmstb driver (Florian Fainelli and Markus Mayer).

- A new tegra driver and cleanup for the existing one (Sumit Gupta and
  Jon Hunter).

- Bandwidth level support for Qcom driver along with OPP changes (Sibi
  Sankar).

- Cleanups to sti, cpufreq-dt, ap806, CPPC drivers (Viresh Kumar, Lee
  Jones, Ivan Kokshaysky, Sven Auhagen, and Xin Hao).

- Make schedutil default governor for ARM (Valentin Schneider).

- Fix dependency issues for imx (Walter Lozano).

- Cleanup around cached_resolved_idx in cpufreq core (Viresh Kumar)."

* 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
  cpufreq: make schedutil the default for arm and arm64
  cpufreq: cached_resolved_idx can not be negative
  cpufreq: Add Tegra194 cpufreq driver
  dt-bindings: arm: Add NVIDIA Tegra194 CPU Complex binding
  cpufreq: imx: Select NVMEM_IMX_OCOTP
  cpufreq: sti-cpufreq: Fix some formatting and misspelling issues
  cpufreq: tegra186: Simplify probe return path
  cpufreq: CPPC: Reuse caps variable in few routines
  cpufreq: ap806: fix cpufreq driver needs ap cpu clk
  cpufreq: cppc: Reorder code and remove apply_hisi_workaround variable
  cpufreq: dt: fix oops on armada37xx
  cpufreq: brcmstb-avs-cpufreq: send S2_ENTER / S2_EXIT commands to AVS
  cpufreq: brcmstb-avs-cpufreq: Support polling AVS firmware
  cpufreq: brcmstb-avs-cpufreq: more flexible interface for __issue_avs_command()
  cpufreq: qcom: Disable fast switch when scaling DDR/L3
  cpufreq: qcom: Update the bandwidth levels on frequency change
  OPP: Add and export helper to set bandwidth
  cpufreq: blacklist SC7180 in cpufreq-dt-platdev
  cpufreq: blacklist SDM845 in cpufreq-dt-platdev
2020-08-04 12:44:53 +02:00
Viresh Kumar 292072c387 cpufreq: cached_resolved_idx can not be negative
It is not possible for cached_resolved_idx to be invalid here as the
cpufreq core always sets index to a positive value.

Change its type to unsigned int and fix qcom usage a bit.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-07-30 11:40:16 +05:30
Quentin Perret 10dd8573b0 cpufreq: Register governors at core_initcall
Currently, most CPUFreq governors are registered at the core_initcall
time when the given governor is the default one, and the module_init
time otherwise.

In preparation for letting users specify the default governor on the
kernel command line, change all of them to be registered at the
core_initcall unconditionally, as it is already the case for the
schedutil and performance governors. This will allow us to assume
that builtin governors have been registered before the built-in
CPUFreq drivers probe.

And since all governors have similar init/exit patterns now, introduce
two new macros, cpufreq_governor_{init,exit}(), to factorize the code.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-07-02 13:03:30 +02:00
Xiongfeng Wang cf6fada715 cpufreq: change '.set_boost' to act on one policy
Macro 'for_each_active_policy()' is defined internally. To avoid some
cpufreq driver needing this macro to iterate over all the policies in
'.set_boost' callback, we redefine '.set_boost' to act on only one
policy and pass the policy as an argument.

'cpufreq_boost_trigger_state()' iterates over all the policies to set
boost for the system.

This is preparation for adding SW BOOST support for CPPC.

To protect Boost enable/disable by sysfs from CPU online/offline,
add 'cpu_hotplug_lock' before calling '.set_boost' for each CPU.

Also move the lock from 'set_boost()' to 'store_cpb()' in
acpi_cpufreq.

Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-06-05 14:20:02 +02:00
Wang Wenhu 2909438d4d cpufreq: fix minor typo in struct cpufreq_driver doc comment
Delete the duplicate "to", possibly double-typed.

Signed-off-by: Wang Wenhu <wenhu.wang@vivo.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-05-14 13:23:09 +02:00
Ionela Voinescu bbce8eaa60 cpufreq: add function to get the hardware max frequency
Add weak function to return the hardware maximum frequency of a CPU,
with the default implementation returning cpuinfo.max_freq, which is
the best information we can generically get from the cpufreq framework.

The default can be overwritten by a strong function in platforms
that want to provide an alternative implementation, with more accurate
information, obtained either from hardware or firmware.

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-03-06 16:02:50 +00:00
Yangtao Li 183edb20e6 cpufreq: Make cpufreq_global_kobject static
The cpufreq_global_kobject is only used internally by cpufreq.c
after commit 2361be2366 ("cpufreq: Don't create empty
/sys/devices/system/cpu/cpufreq directory").

Make it static.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
[ rjw: Add empty line after cpufreq_global_kobject definition ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-02-03 16:56:48 +01:00
Rafael J. Wysocki 1e4f63aecb cpufreq: Avoid creating excessively large stack frames
In the process of modifying a cpufreq policy, the cpufreq core makes
a copy of it including all of the internals which is stored on the
CPU stack.  Because struct cpufreq_policy is relatively large, this
may cause the size of the stack frame to exceed the 2 KB limit and
so the GCC complains when -Wframe-larger-than= is used.

In fact, it is not necessary to copy the entire policy structure
in order to modify it, however.

First, because cpufreq_set_policy() obtains the min and max policy
limits from frequency QoS now, it is not necessary to pass the limits
to it from the callers.  The only things that need to be passed to it
from there are the new governor pointer or (if there is a built-in
governor in the driver) the "policy" value representing the governor
choice.  They both can be passed as individual arguments, though, so
make cpufreq_set_policy() take them this way and rework its callers
accordingly.  This avoids making copies of cpufreq policies in the
callers of cpufreq_set_policy().

Second, cpufreq_set_policy() still needs to pass the new policy
data to the ->verify() callback of the cpufreq driver whose task
is to sanitize the min and max policy limits.  It still does not
need to make a full copy of struct cpufreq_policy for this purpose,
but it needs to pass a few items from it to the driver in case they
are needed (different drivers have different needs in that respect
and all of them have to be covered).  For this reason, introduce
struct cpufreq_policy_data to hold copies of the members of
struct cpufreq_policy used by the existing ->verify() driver
callbacks and pass a pointer to a temporary structure of that
type to ->verify() (instead of passing a pointer to full struct
cpufreq_policy to it).

While at it, notice that intel_pstate and longrun don't really need
to verify the "policy" value in struct cpufreq_policy, so drop those
check from them to avoid copying "policy" into struct
cpufreq_policy_data (which allows it to be slightly smaller).

Also while at it fix up white space in a couple of places and make
cpufreq_set_policy() static (as it can be so).

Fixes: 3000ce3c52 ("cpufreq: Use per-policy frequency QoS")
Link: https://lore.kernel.org/linux-pm/CAMuHMdX6-jb1W8uC2_237m8ctCpsnGp=JCxqt8pCWVqNXHmkVg@mail.gmail.com
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-01-27 10:33:33 +01:00
Rafael J. Wysocki 85572c2c4a cpufreq: Avoid leaving stale IRQ work items during CPU offline
The scheduler code calling cpufreq_update_util() may run during CPU
offline on the target CPU after the IRQ work lists have been flushed
for it, so the target CPU should be prevented from running code that
may queue up an IRQ work item on it at that point.

Unfortunately, that may not be the case if dvfs_possible_from_any_cpu
is set for at least one cpufreq policy in the system, because that
allows the CPU going offline to run the utilization update callback
of the cpufreq governor on behalf of another (online) CPU in some
cases.

If that happens, the cpufreq governor callback may queue up an IRQ
work on the CPU running it, which is going offline, and the IRQ work
may not be flushed after that point.  Moreover, that IRQ work cannot
be flushed until the "offlining" CPU goes back online, so if any
other CPU calls irq_work_sync() to wait for the completion of that
IRQ work, it will have to wait until the "offlining" CPU is back
online and that may not happen forever.  In particular, a system-wide
deadlock may occur during CPU online as a result of that.

The failing scenario is as follows.  CPU0 is the boot CPU, so it
creates a cpufreq policy and becomes the "leader" of it
(policy->cpu).  It cannot go offline, because it is the boot CPU.
Next, other CPUs join the cpufreq policy as they go online and they
leave it when they go offline.  The last CPU to go offline, say CPU3,
may queue up an IRQ work while running the governor callback on
behalf of CPU0 after leaving the cpufreq policy because of the
dvfs_possible_from_any_cpu effect described above.  Then, CPU0 is
the only online CPU in the system and the stale IRQ work is still
queued on CPU3.  When, say, CPU1 goes back online, it will run
irq_work_sync() to wait for that IRQ work to complete and so it
will wait for CPU3 to go back online (which may never happen even
in principle), but (worse yet) CPU0 is waiting for CPU1 at that
point too and a system-wide deadlock occurs.

To address this problem notice that CPUs which cannot run cpufreq
utilization update code for themselves (for example, because they
have left the cpufreq policies that they belonged to), should also
be prevented from running that code on behalf of the other CPUs that
belong to a cpufreq policy with dvfs_possible_from_any_cpu set and so
in that case the cpufreq_update_util_data pointer of the CPU running
the code must not be NULL as well as for the CPU which is the target
of the cpufreq utilization update in progress.

Accordingly, change cpufreq_this_cpu_can_update() into a regular
function in kernel/sched/cpufreq.c (instead of a static inline in a
header file) and make it check the cpufreq_update_util_data pointer
of the local CPU if dvfs_possible_from_any_cpu is set for the target
cpufreq policy.

Also update the schedutil governor to do the
cpufreq_this_cpu_can_update() check in the non-fast-switch
case too to avoid the stale IRQ work issues.

Fixes: 99d14d0e16 ("cpufreq: Process remote callbacks from any CPU if the platform permits")
Link: https://lore.kernel.org/linux-pm/20191121093557.bycvdo4xyinbc5cb@vireshk-i7/
Reported-by: Anson Huang <anson.huang@nxp.com>
Tested-by: Anson Huang <anson.huang@nxp.com>
Cc: 4.14+ <stable@vger.kernel.org> # 4.14+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Peng Fan <peng.fan@nxp.com> (i.MX8QXP-MEK)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-12-12 17:59:43 +01:00
Rafael J. Wysocki 3000ce3c52 cpufreq: Use per-policy frequency QoS
Replace the CPU device PM QoS used for the management of min and max
frequency constraints in cpufreq (and its users) with per-policy
frequency QoS to avoid problems with cpufreq policies covering
more then one CPU.

Namely, a cpufreq driver is registered with the subsys interface
which calls cpufreq_add_dev() for each CPU, starting from CPU0, so
currently the PM QoS notifiers are added to the first CPU in the
policy (i.e. CPU0 in the majority of cases).

In turn, when the cpufreq driver is unregistered, the subsys interface
doing that calls cpufreq_remove_dev() for each CPU, starting from CPU0,
and the PM QoS notifiers are only removed when cpufreq_remove_dev() is
called for the last CPU in the policy, say CPUx, which as a rule is
not CPU0 if the policy covers more than one CPU.  Then, the PM QoS
notifiers cannot be removed, because CPUx does not have them, and
they are still there in the device PM QoS notifiers list of CPU0,
which prevents new PM QoS notifiers from being registered for CPU0
on the next attempt to register the cpufreq driver.

The same issue occurs when the first CPU in the policy goes offline
before unregistering the driver.

After this change it does not matter which CPU is the policy CPU at
the driver registration time and whether or not it is online all the
time, because the frequency QoS is per policy and not per CPU.

Fixes: 67d874c3b2 ("cpufreq: Register notifiers with the PM QoS framework")
Reported-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Reported-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Diagnosed-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/linux-pm/5ad2624194baa2f53acc1f1e627eb7684c577a19.1562210705.git.viresh.kumar@linaro.org/T/#md2d89e95906b8c91c15f582146173dce2e86e99f
Link: https://lore.kernel.org/linux-pm/20191017094612.6tbkwoq4harsjcqv@vireshk-i7/T/#m30d48cc23b9a80467fbaa16e30f90b3828a5a29b
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-10-21 02:05:21 +02:00
Viresh Kumar df0eea4488 cpufreq: Remove CPUFREQ_ADJUST and CPUFREQ_NOTIFY policy notifier events
No driver makes reference to these events now, remove them and the code
related to them.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-09-02 22:44:04 +02:00
Viresh Kumar 6a1490367c cpufreq: Add policy create/remove notifiers back
This effectively reverts some changes made by commit f9f41e3ef9
("cpufreq: Remove policy create/remove notifiers").

We have a new use case for policy create/remove notifiers (for
allocating/freeing QoS requests per policy), so add them back.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-08-10 14:05:48 +02:00
Rafael J. Wysocki 918e162e6a Merge branch 'pm-cpufreq'
* pm-cpufreq:
  cpufreq: Make cpufreq_generic_init() return void
  cpufreq: imx-cpufreq-dt: Add i.MX8MN support
  cpufreq: Add QoS requests for userspace constraints
  cpufreq: intel_pstate: Reuse refresh_frequency_limits()
  cpufreq: Register notifiers with the PM QoS framework
  PM / QoS: Add support for MIN/MAX frequency constraints
  PM / QOS: Pass request type to dev_pm_qos_read_value()
  PM / QOS: Rename __dev_pm_qos_read_value() and dev_pm_qos_raw_read_value()
  PM / QOS: Pass request type to dev_pm_qos_{add|remove}_notifier()
2019-07-18 09:49:30 +02:00
Viresh Kumar c4dcc8a162 cpufreq: Make cpufreq_generic_init() return void
It always returns 0 (success) and its return type should really be void.

Over that, many drivers have added error handling code based on its
return value, which is not required at all.

Change its return type to void and update all the callers.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-07-16 10:20:11 +02:00
Viresh Kumar 18c49926c4 cpufreq: Add QoS requests for userspace constraints
This implements QoS requests to manage userspace configuration of min
and max frequency.

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: syzbot <syzbot+de771ae9390dffed7266@syzkaller.appspotmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-07-08 23:56:39 +02:00
Viresh Kumar c57b25bdf7 cpufreq: intel_pstate: Reuse refresh_frequency_limits()
The implementation of intel_pstate_update_max_freq() is quite similar to
refresh_frequency_limits(), lets reuse it.

Finding minimum of policy->user_policy.max and policy->cpuinfo.max_freq
in intel_pstate_update_max_freq() is redundant as cpufreq_set_policy()
will call the ->verify() callback of intel-pstate driver, which will do
this comparison anyway and so dropping it from
intel_pstate_update_max_freq() doesn't harm.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-07-08 23:56:39 +02:00
Viresh Kumar 67d874c3b2 cpufreq: Register notifiers with the PM QoS framework
Register notifiers for min/max frequency constraints with the PM QoS
framework. The constraints are also taken into consideration in
cpufreq_set_policy().

This also relocates cpufreq_policy_put_kobj() as it is required to be
called from cpufreq_policy_alloc() now.

refresh_frequency_limits() is updated to avoid calling
cpufreq_set_policy() for inactive policies and handle_update() is
updated to have proper locking in place.

No constraints are added until now though.

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-07-08 23:56:13 +02:00
Rafael J. Wysocki 586a07dca8 Merge branch 'pm-cpufreq'
* pm-cpufreq:
  cpufreq: Avoid calling cpufreq_verify_current_freq() from handle_update()
  cpufreq: Consolidate cpufreq_update_current_freq() and __cpufreq_get()
  cpufreq: Don't skip frequency validation for has_target() drivers
  cpufreq: Use has_target() instead of !setpolicy
  cpufreq: Remove redundant !setpolicy check
  cpufreq: Move the IS_ENABLED(CPU_THERMAL) macro into a stub
  cpufreq: s5pv210: Don't flood kernel log after cpufreq change
  cpufreq: pcc-cpufreq: Fail initialization if driver cannot be registered
  cpufreq: add driver for Raspberry Pi
  cpufreq: Switch imx7d to imx-cpufreq-dt for speed grading
  cpufreq: imx-cpufreq-dt: Remove global platform match list
  cpufreq: brcmstb-avs-cpufreq: Fix types for voltage/frequency
  cpufreq: brcmstb-avs-cpufreq: Fix initial command check
  cpufreq: armada-37xx: Remove set but not used variable 'freq'
  cpufreq: imx-cpufreq-dt: Fix no OPPs available on unfused parts
  dt-bindings: imx-cpufreq-dt: Document opp-supported-hw usage
  cpufreq: Add imx-cpufreq-dt driver
2019-07-08 11:00:02 +02:00
Daniel Lezcano bcc6156999 cpufreq: Move the IS_ENABLED(CPU_THERMAL) macro into a stub
cpufreq_online() and cpufreq_offline() [un]register the driver as
a cooling device. This is done if the driver is flagged as a cooling
device in addition with an IS_ENABLED() check to compile out the branching
code.

Group this test in a stub function added in the cpufreq header instead
of having the IS_ENABLED() in the code.

Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-26 10:59:57 +02:00
Thomas Gleixner d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00
Viresh Kumar df24014abe cpufreq: Call transition notifier only once for each policy
Currently, the notifiers are called once for each CPU of the policy->cpus
cpumask. It would be more optimal if the notifier can be called only
once and all the relevant information be provided to it. Out of the 23
drivers that register for the transition notifiers today, only 4 of them
do per-cpu updates and the callback for the rest can be called only once
for the policy without any impact.

This would also avoid multiple function calls to the notifier callbacks
and reduce multiple iterations of notifier core's code (which does
locking as well).

This patch adds pointer to the cpufreq policy to the struct
cpufreq_freqs, so the notifier callback has all the information
available to it with a single call. The five drivers which perform
per-cpu updates are updated to use the cpufreq policy. The freqs->cpu
field is redundant now and is removed.

Acked-by: David S. Miller <davem@davemloft.net> (sparc)
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-05-10 12:20:36 +02:00
Rafael J. Wysocki 9083e49861 cpufreq: intel_pstate: Update max frequency on global turbo changes
While the cpuinfo.max_freq value doesn't really matter for
intel_pstate in the active mode, in the passive mode it is used by
governors as the maximum physical frequency of the CPU and the
results of governor computations generally depend on it.  Also it
is made available to user space via sysfs and it should match the
current HW configuration.

For this reason, make intel_pstate update cpuinfo.max_freq for all
CPUs if it detects a global change of turbo frequency settings from
"disable" to "enable" or the other way associated with a _PPC change
notification from the platform firmware.

Note that policy_is_inactive(),  cpufreq_cpu_acquire(),
cpufreq_cpu_release(), and cpufreq_set_policy() need to be made
available to it for this purpose.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200759
Reported-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-08 11:26:09 +02:00
Rafael J. Wysocki 5a25e3f7cc cpufreq: intel_pstate: Driver-specific handling of _PPC updates
In some cases, the platform firmware disables or enables turbo
frequencies for all CPUs globally before triggering a _PPC change
notification for one of them.  Obviously, that global change affects
all CPUs, not just the notified one, and it needs to be acted upon by
cpufreq.

The intel_pstate driver is able to detect such global changes of
the settings, but it also needs to update policy limits for all
CPUs if that happens, in particular if turbo frequencies are
enabled globally - to allow them to be used.

For this reason, introduce a new cpufreq driver callback to be
invoked on _PPC notifications, if present, instead of simply
calling cpufreq_update_policy() for the notified CPU and make
intel_pstate use it to trigger policy updates for all CPUs
in the system if global settings change.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200759
Reported-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-01 23:43:05 +02:00
Viresh Kumar 91a12e91dc cpufreq: Allow light-weight tear down and bring up of CPUs
The cpufreq core doesn't remove the cpufreq policy anymore on CPU
offline operation, rather that happens when the CPU device gets
unregistered from the kernel. This allows faster recovery when the CPU
comes back online. This is also very useful during system wide
suspend/resume where we offline all non-boot CPUs during suspend and
then bring them back on resume.

This commit takes the same idea a step ahead to allow drivers to do
light weight tear-down and bring-up during CPU offline and online
operations.

A new set of callbacks is introduced, online/offline(). online() gets
called when the first CPU of an inactive policy is brought up and
offline() gets called when all the CPUs of a policy are offlined.

The existing init/exit() callback get called on policy
creation/destruction. They also get called instead of online/offline()
callbacks if the online/offline() callbacks aren't provided.

This also moves around some code to get executed only for the new-policy
case going forward.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-02-12 23:47:42 +01:00
Amit Kucheria 5c238a8b59 cpufreq: Auto-register the driver as a thermal cooling device if asked
All cpufreq drivers do similar things to register as a cooling device.
Provide a cpufreq driver flag so drivers can just ask the cpufreq core
to register the cooling device on their behalf. This allows us to get
rid of duplicated code in the drivers.

In order to allow this, we add a struct thermal_cooling_device pointer
to struct cpufreq_policy so that drivers don't need to store it in a
private data structure.

Suggested-by: Stephen Boyd <swboyd@chromium.org>
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-30 23:02:26 +01:00
Viresh Kumar 625c85a62c cpufreq: Use struct kobj_attribute instead of struct global_attr
The cpufreq_global_kobject is created using kobject_create_and_add()
helper, which assigns the kobj_type as dynamic_kobj_ktype and show/store
routines are set to kobj_attr_show() and kobj_attr_store().

These routines pass struct kobj_attribute as an argument to the
show/store callbacks. But all the cpufreq files created using the
cpufreq_global_kobject expect the argument to be of type struct
attribute. Things work fine currently as no one accesses the "attr"
argument. We may not see issues even if the argument is used, as struct
kobj_attribute has struct attribute as its first element and so they
will both get same address.

But this is logically incorrect and we should rather use struct
kobj_attribute instead of struct global_attr in the cpufreq core and
drivers and the show/store callbacks should take struct kobj_attribute
as argument instead.

This bug is caught using CFI CLANG builds in android kernel which
catches mismatch in function prototypes for such callbacks.

Reported-by: Donghee Han <dh.han@samsung.com>
Reported-by: Sangkyu Kim <skwith.kim@samsung.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-29 11:44:30 +01:00
Amit Kucheria 8321be6a9d cpufreq: Replace open-coded << with BIT()
Minor clean-up to use BIT() and keep checkpatch happy. Clean up the
comment formatting while we're at it to make it easier to read.

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-21 11:02:09 +01:00
Quentin Perret 531b5c9f5c sched/topology: Make Energy Aware Scheduling depend on schedutil
Energy Aware Scheduling (EAS) is designed with the assumption that
frequencies of CPUs follow their utilization value. When using a CPUFreq
governor other than schedutil, the chances of this assumption being true
are small, if any. When schedutil is being used, EAS' predictions are at
least consistent with the frequency requests. Although those requests
have no guarantees to be honored by the hardware, they should at least
guide DVFS in the right direction and provide some hope in regards to the
EAS model being accurate.

To make sure EAS is only used in a sane configuration, create a strong
dependency on schedutil being used. Since having sugov compiled-in does
not provide that guarantee, make CPUFreq call a scheduler function on
governor changes hence letting it rebuild the scheduling domains, check
the governors of the online CPUs, and enable/disable EAS accordingly.

Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adharmap@codeaurora.org
Cc: chris.redpath@arm.com
Cc: currojerez@riseup.net
Cc: dietmar.eggemann@arm.com
Cc: edubezval@gmail.com
Cc: gregkh@linuxfoundation.org
Cc: javi.merino@kernel.org
Cc: joel@joelfernandes.org
Cc: juri.lelli@redhat.com
Cc: morten.rasmussen@arm.com
Cc: patrick.bellasi@arm.com
Cc: pkondeti@codeaurora.org
Cc: skannan@codeaurora.org
Cc: smuckle@google.com
Cc: srinivas.pandruvada@linux.intel.com
Cc: thara.gopinath@linaro.org
Cc: tkjos@google.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Cc: viresh.kumar@linaro.org
Link: https://lkml.kernel.org/r/20181203095628.11858-9-quentin.perret@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-12-11 15:17:00 +01:00
Viresh Kumar 036399782b cpufreq: Rename cpufreq_can_do_remote_dvfs()
This routine checks if the CPU running this code belongs to the policy
of the target CPU or if not, can it do remote DVFS for it remotely. But
the current name of it implies as if it is only about doing remote
updates.

Rename it to make it more relevant.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-23 10:37:08 +02:00
Viresh Kumar 2dd0df8472 cpufreq: Drop cpufreq_table_validate_and_show()
This isn't used anymore. Remove the helper and update documentation
accordingly.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-04-10 08:40:45 +02:00
Viresh Kumar d417e0691a cpufreq: Validate frequency table in the core
By design, cpufreq drivers are responsible for calling
cpufreq_frequency_table_cpuinfo() from their ->init()
callbacks to validate the frequency table.

However, if a cpufreq driver is buggy and fails to do so properly, it
lead to unexpected behavior of the driver or the cpufreq core at a
later point in time.  It would be better if the core could
validate the frequency table during driver initialization.

To that end, introduce cpufreq_table_validate_and_sort() and make
the cpufreq core call it right after invoking the ->init() callback
of the driver and destroy the cpufreq policy if the table is invalid.

For the time being the validation of the table happens twice, once
from the driver and then from the core.  The individual drivers will
be updated separately to drop table validation if they don't need it
for other reasons.

The frequency table is marked "sorted" or "unsorted" by the new helper
now instead of in cpufreq_table_validate_and_show(), as it should only
be done after validating the table (which the drivers won't do going
forward).

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject/changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-02-27 18:22:12 +01:00
Dominik Brodowski ffd81dcfef cpufreq: Add and use cpufreq_for_each_{valid_,}entry_idx()
Pointer subtraction is slow and tedious. Therefore, replace all instances
where cpufreq_for_each_{valid_,}entry loops contained such substractions
with an iteration macro providing an index to the frequency_table entry.

Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Link: http://lkml.kernel.org/r/20180120020237.GM13338@ZenIV.linux.org.uk
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-02-08 10:21:39 +01:00
Rafael J. Wysocki 7d5905dc14 x86 / CPU: Always show current CPU frequency in /proc/cpuinfo
After commit 890da9cf09 (Revert "x86: do not use cpufreq_quick_get()
for /proc/cpuinfo "cpu MHz"") the "cpu MHz" number in /proc/cpuinfo
on x86 can be either the nominal CPU frequency (which is constant)
or the frequency most recently requested by a scaling governor in
cpufreq, depending on the cpufreq configuration.  That is somewhat
inconsistent and is different from what it was before 4.13, so in
order to restore the previous behavior, make it report the current
CPU frequency like the scaling_cur_freq sysfs file in cpufreq.

To that end, modify the /proc/cpuinfo implementation on x86 to use
aperfmperf_snapshot_khz() to snapshot the APERF and MPERF feedback
registers, if available, and use their values to compute the CPU
frequency to be reported as "cpu MHz".

However, do that carefully enough to avoid accumulating delays that
lead to unacceptable access times for /proc/cpuinfo on systems with
many CPUs.  Run aperfmperf_snapshot_khz() once on all CPUs
asynchronously at the /proc/cpuinfo open time, add a single delay
upfront (if necessary) at that point and simply compute the current
frequency while running show_cpuinfo() for each individual CPU.

Also, to avoid slowing down /proc/cpuinfo accesses too much, reduce
the default delay between consecutive APERF and MPERF reads to 10 ms,
which should be sufficient to get large enough numbers for the
frequency computation in all cases.

Fixes: 890da9cf09 (Revert "x86: do not use cpufreq_quick_get() for /proc/cpuinfo "cpu MHz"")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
2017-11-15 19:46:50 +01:00
Dietmar Eggemann e7d5459dfa cpufreq: provide default frequency-invariance setter function
Frequency-invariant accounting support based on the ratio of current
frequency and maximum supported frequency is an optional feature an arch
can implement.

Since there are cpufreq drivers (e.g. cpufreq-dt) which can be build for
different arch's a default implementation of the frequency-invariance
setter function arch_set_freq_scale() is needed.

This default implementation is an empty weak function which will be
overwritten by a strong function in case the arch provides one.

The setter function passes the cpumask of related (to the frequency
change) cpus (online and offline cpus), the (new) current frequency and
the maximum supported frequency.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-10-03 02:37:53 +02:00
Rafael J. Wysocki 08a10002be Merge branch 'pm-cpufreq-sched'
* pm-cpufreq-sched:
  cpufreq: schedutil: Always process remote callback with slow switching
  cpufreq: schedutil: Don't restrict kthread to related_cpus unnecessarily
  cpufreq: Return 0 from ->fast_switch() on errors
  cpufreq: Simplify cpufreq_can_do_remote_dvfs()
  cpufreq: Process remote callbacks from any CPU if the platform permits
  sched: cpufreq: Allow remote cpufreq callbacks
  cpufreq: schedutil: Use unsigned int for iowait boost
  cpufreq: schedutil: Make iowait boost more energy efficient
2017-09-04 00:05:22 +02:00