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commit 1b0289848d5d ("cpufreq: powernv: Add sysfs attributes to show
throttle stats") used policy->driver_data as a flag for one-time creation
of throttle sysfs files. Instead of this use 'kernfs_find_and_get()' to
check if the attribute already exists. This is required as
policy->driver_data is used for other purposes in the later patch.
Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Signed-off-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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module
The IS_ENABLED() macro checks if a Kconfig symbol has been enabled either
built-in or as a module, use that macro instead of open coding the same.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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When the config TDP level is not nominal (level = 0), the MSR values for
reading level 1 and level 2 ratios contain power in low 14 bits and actual
ratio bits are at bits [23:16]. The current processing for level 1 and
level 2 is wrong as there is no shift done to get actual ratio.
Fixes: 6a35fc2d6c22 (cpufreq: intel_pstate: get P1 from TAR when available)
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 4.4+ <stable@vger.kernel.org> # 4.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The way cpufreq_governor_start() initializes j_cdbs->prev_load is
questionable.
First off, j_cdbs->prev_cpu_wall used as a denominator in the
computation may be zero. The case this happens is when
get_cpu_idle_time_us() returns -1 and get_cpu_idle_time_jiffy()
used to return that number is called exactly at the jiffies_64
wrap time. It is rather hard to trigger that error, but it is not
impossible and it will just crash the kernel then.
Second, j_cdbs->prev_load is computed as the average load during
the entire time since the system started and it may not reflect the
load in the previous sampling period (as it is expected to).
That doesn't play well with the way dbs_update() uses that value.
Namely, if the update time delta (wall_time) happens do be greater
than twice the sampling rate on the first invocation of it, the
initial value of j_cdbs->prev_load (which may be completely off) will
be returned to the caller as the current load (unless it is equal to
zero and unless another CPU sharing the same policy object has a
greater load value).
For this reason, notice that the prev_load field of struct cpu_dbs_info
is only used by dbs_update() and only in that one place, so if
cpufreq_governor_start() is modified to always initialize it to 0,
it will make dbs_update() always compute the actual load first time
it checks the update time delta against the doubled sampling rate
(after initialization) and there won't be any side effects of it.
Consequently, modify cpufreq_governor_start() as described.
Fixes: 18b46abd0009 (cpufreq: governor: Be friendly towards latency-sensitive bursty workloads)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The cpufreq-dt-platdev driver supports creation of cpufreq-dt platform
device now, reuse that and remove similar code from platform code.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq-dt-platdev driver supports creation of cpufreq-dt platform
device now, reuse that and remove similar code from platform code.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq-dt-platdev driver supports creation of cpufreq-dt platform
device now, reuse that and remove similar code from platform code.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq-dt-platdev driver supports creation of cpufreq-dt platform
device now, reuse that and remove similar code from platform code.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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This patch add rockchip's compatible string to the compat list and
remove similar code from platform code for supporting generic platdev
driver.
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq-dt-platdev driver supports creation of cpufreq-dt platform
device now, reuse that and remove similar code from platform code.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq-dt-platdev driver supports creation of cpufreq-dt platform
device now, reuse that and remove similar code from platform code.
Note that the complete routine imx27_dt_init() is removed as
of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
has same effect as a NULL .init_machine machine callback pointer.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq-dt-platdev driver supports creation of cpufreq-dt platform
device now, reuse that and remove similar code from platform code.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The machines array in cpufreq-dt-platdev is used only once at boot time
and so should be marked with __initconst, so that kernel can free up
memory used for it, if required.
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Cooling device is registered by ready callback. It's also invoked while
system resuming from sleep (Enabling non-boot cpus). Thus cooling device
may be multiple registered. Matchable unregistration is added to exit
callback to fix this issue.
Signed-off-by: Jia Hongtao <hongtao.jia@nxp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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.exit callback (qoriq_cpufreq_cpu_exit()) is also used during suspend.
So __exit macro should be removed or the function will be discarded.
Signed-off-by: Jia Hongtao <hongtao.jia@nxp.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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When THERMAL_OF is undefined the cooling device messages should not be
shown. -ENOSYS is returned from of_cpufreq_cooling_register() when
THERMAL_OF is undefined.
Signed-off-by: Jia Hongtao <hongtao.jia@nxp.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Add a function to cleanup at module exit and export
appropriate GPL string to enable moduler support
for the cppc_cpufreq driver.
Reported-by: Srinivas Pandruvada <srinivas.pandruvada@intel.com>
Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The result returned by pid_calc() is subtracted from current_pstate
(which is the P-State requested during the last period) in order to
obtain the target P-State for the current iteration.
However, current_pstate may not reflect the real current P-State of
the CPU. In particular, that P-State may be higher because of the
frequency sharing per module.
The theory is:
- The load is the percentage of time spent in C0 and is related to
the average P-State during the same period.
- The last requested P-State can be completely different than the
average P-State (because of frequency sharing or throttling).
- The P-State shift computed by the pid_calc is based on the load
computed at average P-State, so the shift must be relative to
this average P-State.
Using the average P-State instead of current P-State improves power
without significant performance penalty in cases when a task migrates
from one core to other core sharing frequency and voltage.
Performance and power comparison with this patch on Cherry Trail
platform using Android:
Benchmark ?Perf ?Power
FishTank 10.45% 3.1%
SmartBench-Gaming -0.1% -10.4%
SmartBench-Productivity -0.8% -10.4%
CandyCrush n/a -17.4%
AngryBirds n/a -5.9%
videoPlayback n/a -13.9%
audioPlayback n/a -4.9%
IcyRocks-20-50 0.0% -38.4%
iozone RR -0.16% -1.3%
iozone RW 0.74% -1.3%
Signed-off-by: Philippe Longepe <philippe.longepe@linux.intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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CONFIG_HZ_PERIODIC"
Revert commit 0df35026c6a5 (cpufreq: governor: Fix negative idle_time
when configured with CONFIG_HZ_PERIODIC) that introduced a regression
by causing the ondemand cpufreq governor to misbehave for
CONFIG_TICK_CPU_ACCOUNTING unset (the frequency goes up to the max at
one point and stays there indefinitely).
The revert takes subsequent modifications of the code in question into
account.
Fixes: 0df35026c6a5 (cpufreq: governor: Fix negative idle_time when configured with CONFIG_HZ_PERIODIC)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=115261
Reported-and-tested-by: Timo Valtoaho <timo.valtoaho@gmail.com>
Cc: 4.5+ <stable@vger.kernel.org> # 4.5+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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* pm-cpufreq-fixes:
cpufreq: Abort cpufreq_update_current_freq() for cpufreq_suspended set
intel_pstate: Avoid getting stuck in high P-states when idle
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Since governor operations are generally skipped if cpufreq_suspended
is set, cpufreq_start_governor() should do nothing in that case.
That function is called in the cpufreq_online() path, and may also
be called from cpufreq_offline() in some cases, which are invoked
by the nonboot CPUs disabing/enabling code during system suspend
to RAM and resume. That happens when all devices have been
suspended, so if the cpufreq driver relies on things like I2C to
get the current frequency, it may not be ready to do that then.
To prevent problems from happening for this reason, make
cpufreq_update_current_freq(), which is the only function invoked
by cpufreq_start_governor() that doesn't check cpufreq_suspended
already, return 0 upfront if cpufreq_suspended is set.
Fixes: 3bbf8fe3ae08 (cpufreq: Always update current frequency before startig governor)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: iommu@lists.linux-foundation.org
Cc: linux-pm@vger.kernel.org
Cc: oprofile-list@lists.sf.net
Link: http://lkml.kernel.org/r/1459801503-15600-8-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The Kconfig for this driver is currently:
config CPU_FREQ_CBE_PMI
bool "CBE frequency scaling using PMI interface"
...meaning that it currently is not being built as a module by
anyone. Lets remove the modular and unused code here, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Christian Krafft <krafft@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-pm@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Jörg Otte reports that commit a4675fbc4a7a (cpufreq: intel_pstate:
Replace timers with utilization update callbacks) caused the CPUs in
his Haswell-based system to stay in the very high frequency region
even if the system is completely idle.
That turns out to be an existing problem in the intel_pstate driver's
P-state selection algorithm for Core processors. Namely, all
decisions made by that algorithm are based on the average frequency
of the CPU between sampling events and on the P-state requested on
the last invocation, so it may get stuck at a very hight frequency
even if the utilization of the CPU is very low (in fact, it may get
stuck in a inadequate P-state regardless of the CPU utilization).
The only way to kick it out of that limbo is a sufficiently long idle
period (3 times longer than the prescribed sampling interval), but if
that doesn't happen often enough (eg. due to a timing change like
after the above commit), the P-state of the CPU may be inadequate
pretty much all the time.
To address the most egregious manifestations of that issue, reset the
core_busy value used to determine the next P-state to request if the
utilization of the CPU, determined with the help of the MPERF
feedback register and the TSC, is below 1%.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=115771
Reported-and-tested-by: Jörg Otte <jrg.otte@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The freq-table is stored in struct cpufreq_policy also and there is
absolutely no need of keeping a copy of its reference in struct
acpi_cpufreq_data. Drop it.
Also policy->freq_table can't be NULL in the target() callback, remove
the useless check as well.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Rebase ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Its always set by ->init() and so it will always be there in ->exit().
There is no need to have a special check for just that.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Rebase ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Reorganize the code in cpufreq_add_dev() to avoid using the ret
variable and reduce the indentation level in it.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Merge two switch entries that do the same thing in
cpufreq_cpu_callback().
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Use the more common kernel style adding a define for pr_fmt.
Miscellanea:
o Remove now unused PFX defines
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Use the more common logging style.
Miscellanea:
o Coalesce formats
o Realign arguments
o Add a missing space between a coalesced format
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Prefix the output using the more common kernel style.
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Rebase ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Use list_for_each_entry*() instead of list_for_each*() to simplify
the code.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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There are multiple places in intel_pstate where int_tofp() is applied
to both arguments of div_fp(), but this is pointless, because int_tofp()
simply shifts its argument to the left by FRAC_BITS which mathematically
is equivalent to multuplication by 2^FRAC_BITS, so if this is done
to both arguments of a division, the extra factors will cancel each
other during that operation anyway.
Drop the pointless int_tofp() applied to div_fp() arguments throughout
the driver.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq-dt-platdev driver supports creation of cpufreq-dt platform
device now, reuse that and remove similar code from platform code.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Multiple platforms are using the generic cpufreq-dt driver now, and all
of them are required to create a platform device with name "cpufreq-dt",
in order to get the cpufreq-dt probed.
Many of them do it from platform code, others have special drivers just
to do that.
It would be more sensible to do this at a generic place, where all such
platform can mark their entries.
This patch adds a separate file to get this device created. Currently
the compat list of platforms that we support is empty, and will be
filled in as and when we move platforms to use it.
It always compiles as part of the kernel and so doesn't need a
module-exit operation.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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All CPUs on Tegra platform share clock/voltage lines and there is
absolutely no need of setting platform data for 'cpufreq-dt' platform
device, as that's the default case.
Stop setting platform data for cpufreq-dt device.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The Kconfig for this driver is currently:
config CPU_FREQ_CBE_PMI
bool "CBE frequency scaling using PMI interface"
...meaning that it currently is not being built as a module by
anyone. Lets remove the modular and unused code here, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Due to differences in the cpufreq core's handling of runtime CPU
offline and nonboot CPUs disabling during system suspend-to-RAM,
fast frequency switching gets disabled after a suspend-to-RAM and
resume cycle on all of the nonboot CPUs.
To prevent that from happening, move the invocation of
cpufreq_disable_fast_switch() from cpufreq_exit_governor() to
sugov_exit(), as the schedutil governor is the only user of fast
frequency switching today anyway.
That simply prevents cpufreq_disable_fast_switch() from being called
without invoking the ->governor callback for the CPUFREQ_GOV_POLICY_EXIT
event (which happens during system suspend now).
Fixes: b7898fda5bc7 (cpufreq: Support for fast frequency switching)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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* pm-cpufreq:
cpufreq: dt: Drop stale comment
cpufreq: intel_pstate: Documenation for structures
cpufreq: intel_pstate: fix inconsistency in setting policy limits
intel_pstate: Avoid extra invocation of intel_pstate_sample()
intel_pstate: Do not set utilization update hook too early
* pm-cpuidle:
intel_idle: Add KBL support
intel_idle: Add SKX support
intel_idle: Clean up all registered devices on exit.
intel_idle: Propagate hot plug errors.
intel_idle: Don't overreact to a cpuidle registration failure.
intel_idle: Setup the timer broadcast only on successful driver load.
intel_idle: Avoid a double free of the per-CPU data.
intel_idle: Fix dangling registration on error path.
intel_idle: Fix deallocation order on the driver exit path.
intel_idle: Remove redundant initialization calls.
intel_idle: Fix a helper function's return value.
intel_idle: remove useless return from void function.
* acpi-cppc:
mailbox: pcc: Don't access an unmapped memory address space
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The comment in file header doesn't hold true anymore, drop it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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No code change. Only added kernel doc style comments for structures.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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When user sets performance policy using cpufreq interface, it is possible
that because of policy->max limits, the actual performance is still
limited. But the current implementation will silently switch the
policy to powersave and start using powersave limits. If user modifies
any limits using intel_pstate sysfs, this is actually changing powersave
limits.
The current implementation tracks limits under powersave and performance
policy using two different variables. When policy->max is less than
policy->cpuinfo.max_freq, only powersave limit variable is used.
This fix causes the performance limits variable to be used always when
the policy is performance.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Add a new cpufreq scaling governor, called "schedutil", that uses
scheduler-provided CPU utilization information as input for making
its decisions.
Doing that is possible after commit 34e2c555f3e1 (cpufreq: Add
mechanism for registering utilization update callbacks) that
introduced cpufreq_update_util() called by the scheduler on
utilization changes (from CFS) and RT/DL task status updates.
In particular, CPU frequency scaling decisions may be based on
the the utilization data passed to cpufreq_update_util() by CFS.
The new governor is relatively simple.
The frequency selection formula used by it depends on whether or not
the utilization is frequency-invariant. In the frequency-invariant
case the new CPU frequency is given by
next_freq = 1.25 * max_freq * util / max
where util and max are the last two arguments of cpufreq_update_util().
In turn, if util is not frequency-invariant, the maximum frequency in
the above formula is replaced with the current frequency of the CPU:
next_freq = 1.25 * curr_freq * util / max
The coefficient 1.25 corresponds to the frequency tipping point at
(util / max) = 0.8.
All of the computations are carried out in the utilization update
handlers provided by the new governor. One of those handlers is
used for cpufreq policies shared between multiple CPUs and the other
one is for policies with one CPU only (and therefore it doesn't need
to use any extra synchronization means).
The governor supports fast frequency switching if that is supported
by the cpufreq driver in use and possible for the given policy.
In the fast switching case, all operations of the governor take
place in its utilization update handlers. If fast switching cannot
be used, the frequency switch operations are carried out with the
help of a work item which only calls __cpufreq_driver_target()
(under a mutex) to trigger a frequency update (to a value already
computed beforehand in one of the utilization update handlers).
Currently, the governor treats all of the RT and DL tasks as
"unknown utilization" and sets the frequency to the allowed
maximum when updated from the RT or DL sched classes. That
heavy-handed approach should be replaced with something more
subtle and specifically targeted at RT and DL tasks.
The governor shares some tunables management code with the
"ondemand" and "conservative" governors and uses some common
definitions from cpufreq_governor.h, but apart from that it
is stand-alone.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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Modify the ACPI cpufreq driver to provide a method for switching
CPU frequencies from interrupt context and update the cpufreq core
to support that method if available.
Introduce a new cpufreq driver callback, ->fast_switch, to be
invoked for frequency switching from interrupt context by (future)
governors supporting that feature via (new) helper function
cpufreq_driver_fast_switch().
Add two new policy flags, fast_switch_possible, to be set by the
cpufreq driver if fast frequency switching can be used for the
given policy and fast_switch_enabled, to be set by the governor
if it is going to use fast frequency switching for the given
policy. Also add a helper for setting the latter.
Since fast frequency switching is inherently incompatible with
cpufreq transition notifiers, make it possible to set the
fast_switch_enabled only if there are no transition notifiers
already registered and make the registration of new transition
notifiers fail if fast_switch_enabled is set for at least one
policy.
Implement the ->fast_switch callback in the ACPI cpufreq driver
and make it set fast_switch_possible during policy initialization
as appropriate.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Move definitions of symbols related to transition latency and
sampling rate to include/linux/cpufreq.h so they can be used by
(future) goverernors located outside of drivers/cpufreq/.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Move definitions and function headers related to struct gov_attr_set
to include/linux/cpufreq.h so they can be used by (future) goverernors
located outside of drivers/cpufreq/.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Move abstract code related to struct gov_attr_set to a separate (new)
file so it can be shared with (future) goverernors that won't share
more code with "ondemand" and "conservative".
No intentional functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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