Commit Graph

121 Commits

Author SHA1 Message Date
Stratos Karafotis 880eef0416 cpufreq: ondemand: Remove redundant return statement
After commit dfa5bb6225 (cpufreq: ondemand: Change the calculation
of target frequency), this return statement is no longer needed.

Reported-by: Henrik Nilsson <Karl.Henrik.Nilsson@gmail.com>
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>
2013-11-01 00:44:34 +01:00
Stratos Karafotis 934dac1ea0 cpufreq: governors: Remove duplicate check of target freq in supported range
Function __cpufreq_driver_target() checks if target_freq is within
policy->min and policy->max range. generic_powersave_bias_target() also
checks if target_freq is valid via a cpufreq_frequency_table_target()
call. So, drop the unnecessary duplicate check in *_check_cpu().

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>
2013-08-28 22:03:02 +02:00
Rafael J. Wysocki c49a089c3e Merge back earlier 'pm-cpufreq' material 2013-08-14 22:21:16 +02:00
Viresh Kumar d5b73cd870 cpufreq: Use sizeof(*ptr) convetion for computing sizes
Chapter 14 of Documentation/CodingStyle says:

The preferred form for passing a size of a struct is the following:

	p = kmalloc(sizeof(*p), ...);

The alternative form where struct name is spelled out hurts
readability and introduces an opportunity for a bug when the pointer
variable type is changed but the corresponding sizeof that is passed
to a memory allocator is not.

This wasn't followed consistently in drivers/cpufreq, let's make it
more consistent by always following this rule.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-08-07 23:34:10 +02:00
Viresh Kumar 3a3e9e06d0 cpufreq: Give consistent names to cpufreq_policy objects
They are called policy, cur_policy, new_policy, data, etc.  Just call
them policy wherever possible.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-08-07 23:34:10 +02:00
Viresh Kumar 5ff0a26803 cpufreq: Clean up header files included in the core
This patch addresses the following issues in the header files in the
cpufreq core:
 - Include headers in ascending order, so that we don't add same
   many times by mistake.
 - <asm/> must be included after <linux/>, so that they override
   whatever they need to.
 - Remove unnecessary includes.
 - Don't include files already included by cpufreq.h or
   cpufreq_governor.h.

[rjw: Changelog]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-08-07 23:34:09 +02:00
Viresh Kumar 6c4640c3ad cpufreq: rename ignore_nice as ignore_nice_load
This sysfs file was called ignore_nice_load earlier and commit
4d5dcc4 (cpufreq: governor: Implement per policy instances of
governors) changed its name to ignore_nice by mistake.

Lets get it renamed back to its original name.

Reported-by: Martin von Gagern <Martin.vGagern@gmx.net>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 3.10+ <stable@vger.kernel.org> # 3.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-08-07 22:25:06 +02:00
Stratos Karafotis dfa5bb6225 cpufreq: ondemand: Change the calculation of target frequency
The ondemand governor calculates load in terms of frequency and
increases it only if load_freq is greater than up_threshold
multiplied by the current or average frequency.  This appears to
produce oscillations of frequency between min and max because,
for example, a relatively small load can easily saturate minimum
frequency and lead the CPU to the max.  Then, it will decrease
back to the min due to small load_freq.

Change the calculation method of load and target frequency on the
basis of the following two observations:

 - Load computation should not depend on the current or average
   measured frequency.  For example, absolute load of 80% at 100MHz
   is not necessarily equivalent to 8% at 1000MHz in the next
   sampling interval.

 - It should be possible to increase the target frequency to any
   value present in the frequency table proportional to the absolute
   load, rather than to the max only, so that:

   Target frequency = C * load

   where we take C = policy->cpuinfo.max_freq / 100.

Tested on Intel i7-3770 CPU @ 3.40GHz and on Quad core 1500MHz Krait.
Phoronix benchmark of Linux Kernel Compilation 3.1 test shows an
increase ~1.5% in performance. cpufreq_stats (time_in_state) shows
that middle frequencies are used more, with this patch.  Highest
and lowest frequencies were used less by ~9%.

[rjw: We have run multiple other tests on kernels with this
 change applied and in the vast majority of cases it turns out
 that the resulting performance improvement also leads to reduced
 consumption of energy.  The change is additionally justified by
 the overall simplification of the code in question.]

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>
2013-07-26 01:06:43 +02:00
Jacob Shin c28375583b cpufreq: fix NULL pointer deference at od_set_powersave_bias()
When initializing the default powersave_bias value, we need to first
make sure that this policy is running the ondemand governor.

Reported-and-tested-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-06-25 22:42:37 +02:00
Borislav Petkov 60e6726c7b cpufreq, ondemand: Remove leftover debug line
I don't see how the virtual address of the tuners pointer would be of
any help to anyone so remove it.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-13 14:02:31 +02:00
Jacob Shin fb30809efa cpufreq: ondemand: allow custom powersave_bias_target handler to be registered
This allows for another [arch specific] driver to hook into existing
powersave bias function of the ondemand governor. i.e. This allows AMD
specific powersave bias function (in a separate AMD specific driver)
to aid ondemand governor's frequency transition decisions.

Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Thomas Renninger <trenn@suse.de>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-10 13:19:26 +02:00
Stratos Karafotis 9366d84052 cpufreq: governors: Calculate iowait time only when necessary
Currently we always calculate the CPU iowait time and add it to idle time.
If we are in ondemand and we use io_is_busy, we re-calculate iowait time
and we subtract it from idle time.

With this patch iowait time is calculated only when necessary avoiding
the double call to get_cpu_iowait_time_us. We use a parameter in
function get_cpu_idle_time to distinguish when the iowait time will be
added to idle time or not, without the need of keeping the prev_io_wait.

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>
2013-04-01 01:11:35 +02:00
Viresh Kumar 031299b3be cpufreq: governors: Avoid unnecessary per cpu timer interrupts
Following patch has introduced per cpu timers or works for ondemand and
conservative governors.

	commit 2abfa876f1
	Author: Rickard Andersson <rickard.andersson@stericsson.com>
	Date:   Thu Dec 27 14:55:38 2012 +0000

	    cpufreq: handle SW coordinated CPUs

This causes additional unnecessary interrupts on all cpus when the load is
recently evaluated by any other cpu. i.e. When load is recently evaluated by cpu
x, we don't really need any other cpu to evaluate this load again for the next
sampling_rate time.

Some sort of code is present to avoid that but we are still getting timer
interrupts for all cpus. A good way of avoiding this would be to modify delays
for all cpus (policy->cpus) whenever any cpu has evaluated load.

This patch does this change and some related code cleanup.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-01 01:11:35 +02:00
Viresh Kumar 9d44592018 cpufreq: ondemand: Don't update sample_type if we don't evaluate load again
Because we have per cpu timer now, we check if we need to evaluate load again or
not (In case it is recently evaluated). Here the 2nd cpu which got timer
interrupt updates core_dbs_info->sample_type irrespective of load evaluation is
required or not. Which is wrong as the first cpu is dependent on this variable
set to an older value.

Moreover it would be best in this case to schedule 2nd cpu's timer to
sampling_rate instead of freq_lo or hi as that must be managed by the other cpu.
In case the other cpu idles in between then also we wouldn't loose much power.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-01 01:11:34 +02:00
Viresh Kumar 4d5dcc4211 cpufreq: governor: Implement per policy instances of governors
Currently, there can't be multiple instances of single governor_type.
If we have a multi-package system, where we have multiple instances
of struct policy (per package), we can't have multiple instances of
same governor. i.e. We can't have multiple instances of ondemand
governor for multiple packages.

Governors directory in sysfs is created at /sys/devices/system/cpu/cpufreq/
governor-name/. Which again reflects that there can be only one
instance of a governor_type in the system.

This is a bottleneck for multicluster system, where we want different
packages to use same governor type, but with different tunables.

This patch uses the infrastructure provided by earlier patch and
implements init/exit routines for ondemand and conservative
governors.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-01 01:11:34 +02:00
Stratos Karafotis 06eb09d17c cpufreq: ondemand: Fix typos in comments
Fix some typos in comments.

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>
2013-02-09 12:56:19 +01:00
Stratos Karafotis 4bd4e42819 cpufreq: ondemand: Replace down_differential tuner with adj_up_threshold
In order to avoid the calculation of up_threshold - down_differential
every time that the frequency must be decreased, we replace the
down_differential tuner with the adj_up_threshold which keeps the
difference across multiple checks.

Update the adj_up_threshold only when the up_theshold is also updated.

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>
2013-02-09 01:18:47 +01:00
Viresh Kumar 4447266b84 cpufreq: governors: Remove code redundancy between governors
With the inclusion of following patches:

9f4eb10 cpufreq: conservative: call dbs_check_cpu only when necessary
772b4b1 cpufreq: ondemand: call dbs_check_cpu only when necessary

code redundancy between the conservative and ondemand governors is
introduced again, so get rid of it.

[rjw: Changelog]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-02-02 01:02:44 +01:00
Fabio Baltieri 09dca5ae75 cpufreq: governors: fix misuse of cdbs.cpu
Fix governors code to set all cpu's cdbs->cpu to the the actual cpu id
and use cur_policy->cpu istead of cdbs->cpu to track current governor's
leader cpu.

Reported-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-02-02 00:01:16 +01:00
Fabio Baltieri 2624f90c16 cpufreq: governors: implement generic policy_is_shared
Implement a generic helper function policy_is_shared() to replace the
current dbs_sw_coordinated_cpus() at cpufreq level, so that it can be
used by code other than cpufreq governors.

Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-02-02 00:01:16 +01:00
Fabio Baltieri 8ee2ec51d0 cpufreq: ondemand: use all CPUs in update_sampling_rate
Modify update_sampling_rate() to check, and eventually immediately
schedule, all CPU's do_dbs_timer delayed work.

This is required in case of software coordinated CPUs, as we now have a
separate delayed work for each CPU.

Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-02-02 00:01:14 +01:00
Fabio Baltieri da53d61e21 cpufreq: ondemand: call dbs_check_cpu only when necessary
Modify ondemand timer to not resample CPU utilization if recently
sampled from another SW coordinated core.

Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-02-02 00:01:13 +01:00
Rickard Andersson 2abfa876f1 cpufreq: handle SW coordinated CPUs
This patch fixes a bug that occurred when we had load on a secondary CPU
and the primary CPU was sleeping. Only one sampling timer was spawned
and it was spawned as a deferred timer on the primary CPU, so when a
secondary CPU had a change in load this was not detected by the cpufreq
governor (both ondemand and conservative).

This patch make sure that deferred timers are run on all CPUs in the
case of software controlled CPUs that run on the same frequency.

Signed-off-by: Rickard Andersson <rickard.andersson@stericsson.com>
Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-02-02 00:01:13 +01:00
Fabio Baltieri 3e33ee9e08 cpufreq: ondemand: update sampling rate only on right CPUs
Fix cpufreq_gov_ondemand to skip CPU where another governor is used.

The bug present itself as NULL pointer access on the mutex_lock() call,
an can be reproduced on an SMP machine by setting the default governor
to anything other than ondemand, setting a single CPU's governor to
ondemand, then changing the sample rate by writing on:

> /sys/devices/system/cpu/cpufreq/ondemand/sampling_rate

Backtrace:

Nov 26 17:36:54 balto kernel: [  839.585241] BUG: unable to handle kernel NULL pointer dereference at           (null)
Nov 26 17:36:54 balto kernel: [  839.585311] IP: [<ffffffff8174e082>] __mutex_lock_slowpath+0xb2/0x170
[snip]
Nov 26 17:36:54 balto kernel: [  839.587005] Call Trace:
Nov 26 17:36:54 balto kernel: [  839.587030]  [<ffffffff8174da82>] mutex_lock+0x22/0x40
Nov 26 17:36:54 balto kernel: [  839.587067]  [<ffffffff81610b8f>] store_sampling_rate+0xbf/0x150
Nov 26 17:36:54 balto kernel: [  839.587110]  [<ffffffff81031e9c>] ?  __do_page_fault+0x1cc/0x4c0
Nov 26 17:36:54 balto kernel: [  839.587153]  [<ffffffff813309bf>] kobj_attr_store+0xf/0x20
Nov 26 17:36:54 balto kernel: [  839.587192]  [<ffffffff811bb62d>] sysfs_write_file+0xcd/0x140
Nov 26 17:36:54 balto kernel: [  839.587234]  [<ffffffff8114c12c>] vfs_write+0xac/0x180
Nov 26 17:36:54 balto kernel: [  839.587271]  [<ffffffff8114c472>] sys_write+0x52/0xa0
Nov 26 17:36:54 balto kernel: [  839.587306]  [<ffffffff810321ce>] ?  do_page_fault+0xe/0x10
Nov 26 17:36:54 balto kernel: [  839.587345]  [<ffffffff81751202>] system_call_fastpath+0x16/0x1b

Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-27 14:11:19 +01:00
Fabio Baltieri d3c31a773f cpufreq: ondemand: fix wrong delay sampling rate
Restore the correct delay value for ondemand's od_dbs_timer, as it was
changed erroneously in commit 83f0e55 (cpufreq: governors: remove
redundant code).

Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-23 20:48:08 +01:00
Viresh Kumar 4471a34f9a cpufreq: governors: remove redundant code
Initially ondemand governor was written and then using its code conservative
governor is written. It used a lot of code from ondemand governor, but copy of
code was created instead of using the same routines from both governors. Which
increased code redundancy, which is difficult to manage.

This patch is an attempt to move common part of both the governors to
cpufreq_governor.c file to come over above mentioned issues.

This shouldn't change anything from functionality point of view.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:33:07 +01:00
viresh kumar 2aacdfff9c cpufreq: Move common part from governors to separate file, v2
Multiple cpufreq governers have defined similar get_cpu_idle_time_***()
routines. These routines must be moved to some common place, so that all
governors can use them.

So moving them to cpufreq_governor.c, which seems to be a better place for
keeping these routines.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:33:06 +01:00
Linus Torvalds 16642a2e7b Power management updates for 3.7-rc1
* Improved system suspend/resume and runtime PM handling for the SH TMU, CMT
   and MTU2 clock event devices (also used by ARM/shmobile).
 
 * Generic PM domains framework extensions related to cpuidle support and
   domain objects lookup using names.
 
 * ARM/shmobile power management updates including improved support for the
   SH7372's A4S power domain containing the CPU core.
 
 * cpufreq changes related to AMD CPUs support from Matthew Garrett, Andre
   Przywara and Borislav Petkov.
 
 * cpu0 cpufreq driver from Shawn Guo.
 
 * cpufreq governor fixes related to the relaxing of limit from Michal Pecio.
 
 * OMAP cpufreq updates from Axel Lin and Richard Zhao.
 
 * cpuidle ladder governor fixes related to the disabling of states from
   Carsten Emde and me.
 
 * Runtime PM core updates related to the interactions with the system suspend
   core from Alan Stern and Kevin Hilman.
 
 * Wakeup sources modification allowing more helper functions to be called from
   interrupt context from John Stultz and additional diagnostic code from Todd
   Poynor.
 
 * System suspend error code path fix from Feng Hong.
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Merge tag 'pm-for-3.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael J Wysocki:

 - Improved system suspend/resume and runtime PM handling for the SH
   TMU, CMT and MTU2 clock event devices (also used by ARM/shmobile).

 - Generic PM domains framework extensions related to cpuidle support
   and domain objects lookup using names.

 - ARM/shmobile power management updates including improved support for
   the SH7372's A4S power domain containing the CPU core.

 - cpufreq changes related to AMD CPUs support from Matthew Garrett,
   Andre Przywara and Borislav Petkov.

 - cpu0 cpufreq driver from Shawn Guo.

 - cpufreq governor fixes related to the relaxing of limit from Michal
   Pecio.

 - OMAP cpufreq updates from Axel Lin and Richard Zhao.

 - cpuidle ladder governor fixes related to the disabling of states from
   Carsten Emde and me.

 - Runtime PM core updates related to the interactions with the system
   suspend core from Alan Stern and Kevin Hilman.

 - Wakeup sources modification allowing more helper functions to be
   called from interrupt context from John Stultz and additional
   diagnostic code from Todd Poynor.

 - System suspend error code path fix from Feng Hong.

Fixed up conflicts in cpufreq/powernow-k8 that stemmed from the
workqueue fixes conflicting fairly badly with the removal of support for
hardware P-state chips.  The changes were independent but somewhat
intertwined.

* tag 'pm-for-3.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (76 commits)
  Revert "PM QoS: Use spinlock in the per-device PM QoS constraints code"
  PM / Runtime: let rpm_resume() succeed if RPM_ACTIVE, even when disabled, v2
  cpuidle: rename function name "__cpuidle_register_driver", v2
  cpufreq: OMAP: Check IS_ERR() instead of NULL for omap_device_get_by_hwmod_name
  cpuidle: remove some empty lines
  PM: Prevent runtime suspend during system resume
  PM QoS: Use spinlock in the per-device PM QoS constraints code
  PM / Sleep: use resume event when call dpm_resume_early
  cpuidle / ACPI : move cpuidle_device field out of the acpi_processor_power structure
  ACPI / processor: remove pointless variable initialization
  ACPI / processor: remove unused function parameter
  cpufreq: OMAP: remove loops_per_jiffy recalculate for smp
  sections: fix section conflicts in drivers/cpufreq
  cpufreq: conservative: update frequency when limits are relaxed
  cpufreq / ondemand: update frequency when limits are relaxed
  properly __init-annotate pm_sysrq_init()
  cpufreq: Add a generic cpufreq-cpu0 driver
  PM / OPP: Initialize OPP table from device tree
  ARM: add cpufreq transiton notifier to adjust loops_per_jiffy for smp
  cpufreq: Remove support for hardware P-state chips from powernow-k8
  ...
2012-10-02 18:32:35 -07:00
Michal Pecio f26365179d cpufreq / ondemand: update frequency when limits are relaxed
Reevaluate CPU load and update frequency immediately whenever limits
are changed. Currently ondemand doesn't do that when limits are
relaxed, wasting power on systems with relatively low sampling rate.

Signed-off-by: Michal Pecio <mpecio@nvidia.com>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-09-14 21:07:39 +02:00
Tejun Heo 203b42f731 workqueue: make deferrable delayed_work initializer names consistent
Initalizers for deferrable delayed_work are confused.

* __DEFERRED_WORK_INITIALIZER()
* DECLARE_DEFERRED_WORK()
* INIT_DELAYED_WORK_DEFERRABLE()

Rename them to

* __DEFERRABLE_WORK_INITIALIZER()
* DECLARE_DEFERRABLE_WORK()
* INIT_DEFERRABLE_WORK()

This patch doesn't cause any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
2012-08-21 13:18:23 -07:00
MyungJoo Ham fd0ef7a058 [CPUFREQ] CPUfreq ondemand: update sampling rate without waiting for next sampling
When a new sampling rate is shorter than the current one, (e.g., 1 sec
--> 10 ms) regardless how short the new one is, the current ondemand
mechanism wait for the previously set timer to be expired.

For example, if the user has just expressed that the sampling rate
should be 10 ms from now and the previous was 1000 ms, the new rate may
become effective 999 ms later, which could be not acceptable for the
user if the user has intended to speed up sampling because the system is
expected to react to CPU load fluctuation quickly from __now__.

In order to address this issue, we need to cancel the previously set
timer (schedule_delayed_work) and reset the timer if resetting timer is
expected to trigger the delayed_work ealier.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2012-02-29 22:24:40 -05:00
Linus Torvalds 02d929502c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq: (23 commits)
  [CPUFREQ] EXYNOS: Removed useless headers and codes
  [CPUFREQ] EXYNOS: Make EXYNOS common cpufreq driver
  [CPUFREQ] powernow-k8: Update copyright, maintainer and documentation information
  [CPUFREQ] powernow-k8: Fix indexing issue
  [CPUFREQ] powernow-k8: Avoid Pstate MSR accesses on systems supporting CPB
  [CPUFREQ] update lpj only if frequency has changed
  [CPUFREQ] cpufreq:userspace: fix cpu_cur_freq updation
  [CPUFREQ] Remove wall variable from cpufreq_gov_dbs_init()
  [CPUFREQ] EXYNOS4210: cpufreq code is changed for stable working
  [CPUFREQ] EXYNOS4210: Update frequency table for cpu divider
  [CPUFREQ] EXYNOS4210: Remove code about bus on cpufreq
  [CPUFREQ] s3c64xx: Use pr_fmt() for consistent log messages
  cpufreq: OMAP: fixup for omap_device changes, include <linux/module.h>
  cpufreq: OMAP: fix freq_table leak
  cpufreq: OMAP: put clk if cpu_init failed
  cpufreq: OMAP: only supports OPP library
  cpufreq: OMAP: dont support !freq_table
  cpufreq: OMAP: deny initialization if no mpudev
  cpufreq: OMAP: move clk name decision to init
  cpufreq: OMAP: notify even with bad boot frequency
  ...
2012-01-11 18:53:33 -08:00
Martin Schwidefsky 612ef28a04 Merge branch 'sched/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into cputime-tip
Conflicts:
	drivers/cpufreq/cpufreq_conservative.c
	drivers/cpufreq/cpufreq_ondemand.c
	drivers/macintosh/rack-meter.c
	fs/proc/stat.c
	fs/proc/uptime.c
	kernel/sched/core.c
2011-12-19 19:23:15 +01:00
Martin Schwidefsky 648616343c [S390] cputime: add sparse checking and cleanup
Make cputime_t and cputime64_t nocast to enable sparse checking to
detect incorrect use of cputime. Drop the cputime macros for simple
scalar operations. The conversion macros are still needed.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-12-15 14:56:19 +01:00
Kamalesh Babulal 21f2e3c86b [CPUFREQ] Remove wall variable from cpufreq_gov_dbs_init()
CPUFREQ Remove wall variable from cpufreq_gov_dbs_init()

Remove wall variable from cpufreq_gov_dbs_init() as
get_cpu_idle_time_us() no longer updates the last_update_time
unconditionally. Passing non-NULL last_update_time address
will result in accounting additional idle time with
update_ts_time_stats() before returning idle_sleeptime.

Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Dave Jones <davej@redhat.com>
--
 drivers/cpufreq/cpufreq_ondemand.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
2011-12-09 10:40:23 -05:00
Glauber Costa 3292beb340 sched/accounting: Change cpustat fields to an array
This patch changes fields in cpustat from a structure, to an
u64 array. Math gets easier, and the code is more flexible.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Tuner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1322498719-2255-2-git-send-email-glommer@parallels.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-06 09:06:38 +01:00
Linus Torvalds 39adff5f69 Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  time, s390: Get rid of compile warning
  dw_apb_timer: constify clocksource name
  time: Cleanup old CONFIG_GENERIC_TIME references that snuck in
  time: Change jiffies_to_clock_t() argument type to unsigned long
  alarmtimers: Fix error handling
  clocksource: Make watchdog reset lockless
  posix-cpu-timers: Cure SMP accounting oddities
  s390: Use direct ktime path for s390 clockevent device
  clockevents: Add direct ktime programming function
  clockevents: Make minimum delay adjustments configurable
  nohz: Remove "Switched to NOHz mode" debugging messages
  proc: Consider NO_HZ when printing idle and iowait times
  nohz: Make idle/iowait counter update conditional
  nohz: Fix update_ts_time_stat idle accounting
  cputime: Clean up cputime_to_usecs and usecs_to_cputime macros
  alarmtimers: Rework RTC device selection using class interface
  alarmtimers: Add try_to_cancel functionality
  alarmtimers: Add more refined alarm state tracking
  alarmtimers: Remove period from alarm structure
  alarmtimers: Remove interval cap limit hack
  ...
2011-10-26 17:15:03 +02:00
Michal Hocko 6beea0cda8 nohz: Fix update_ts_time_stat idle accounting
update_ts_time_stat currently updates idle time even if we are in
iowait loop at the moment. The only real users of the idle counter
(via get_cpu_idle_time_us) are CPU governors and they expect to get
cumulative time for both idle and iowait times.
The value (idle_sleeptime) is also printed to userspace by print_cpu
but it prints both idle and iowait times so the idle part is misleading.

Let's clean this up and fix update_ts_time_stat to account both counters
properly and update consumers of idle to consider iowait time as well.
If we do this we might use get_cpu_{idle,iowait}_time_us from other
contexts as well and we will get expected values.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Jones <davej@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Link: http://lkml.kernel.org/r/e9c909c221a8da402c4da07e4cd968c3218f8eb1.1314172057.git.mhocko@suse.cz
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-09-08 11:10:55 +02:00
Paul Bolle bd74b32b77 Fix documentation and comment typo 'no_hz'
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Acked-by: Len Brown <len.brown@intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-08-08 18:55:59 +02:00
Thomas Renninger 326c86deae [CPUFREQ] Remove unneeded locks
There cannot be any concurrent access to these through
different cpu sysfs files anymore, because these tunables
are now all global (not per cpu).

I still have some doubts whether some of these locks
were needed at all. Anyway, let's get rid of them.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
CC: cpufreq@vger.kernel.org
2011-03-16 17:54:32 -04:00
Thomas Renninger e8951251b8 [CPUFREQ] Remove old, deprecated per cpu ondemand/conservative sysfs files
Marked deprecated for quite a whilte now...

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
CC: cpufreq@vger.kernel.org
2011-03-16 17:54:32 -04:00
Thomas Renninger ef598549b2 [CPUFREQ] Remove deprecated sysfs file sampling_rate_max
Marked deprecated for quite a while now...

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
CC: cpufreq@vger.kernel.org
2011-03-16 17:54:32 -04:00
Vincent Guittot 5cb2c3bd0c [CPUFREQ] calculate delay after dbs_check_cpu
calculate ondemand delay after dbs_check_cpu call because it can
modify rate_mult value

use freq_lo_jiffies value for the sub sample period of powersave_bias mode

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Dave Jones <davej@redhat.com>
2011-03-16 17:54:31 -04:00
Tejun Heo 57df5573a5 cpufreq: use system_wq instead of dedicated workqueues
With cmwq, there's no reason for cpufreq drivers to use separate
workqueues.  Remove the dedicated workqueues from cpufreq_conservative
and cpufreq_ondemand and use system_wq instead.  The work items are
already sync canceled on stop, so it's already guaranteed that no work
is running on module exit.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Dave Jones <davej@redhat.com>
Cc: cpufreq@vger.kernel.org
2011-01-26 12:12:50 +01:00
David C Niemi 3f78a9f7fc [CPUFREQ] add sampling_down_factor tunable to improve ondemand performance
Adds a new global tunable, sampling_down_factor.  Set to 1 it makes no
changes from existing behavior, but set to greater than 1 (e.g. 100)
it acts as a multiplier for the scheduling interval for reevaluating
load when the CPU is at its top speed due to high load.  This improves
performance by reducing the overhead of load evaluation and helping
the CPU stay at its top speed when truly busy, rather than shifting
back and forth in speed.  This tunable has no effect on behavior at
lower speeds/lower CPU loads.

This patch is against 2.6.36-rc6.

This patch should help solve kernel bug 19672 "ondemand is slow".

Signed-off-by: David Niemi <dniemi@verisign.com>
Acked-by: Venkatesh Pallipadi <venki@google.com>
CC: Daniel Hollocher <danielhollocher@gmail.com>
CC: <cpufreq-list@vger.kernel.org>
CC: <linux-kernel@vger.kernel.org>
Signed-off-by: Dave Jones <davej@redhat.com>
2010-10-22 11:44:47 -04:00
Jocelyn Falempe a665df9d51 [CPUFREQ] ondemand: don't synchronize sample rate unless multiple cpus present
For UP systems this is not required, and results in a more consistent
sample interval.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jocelyn Falempe <jocelyn.falempe@motorola.com>
Signed-off-by: Mike Chan <mike@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>
2010-08-03 13:47:04 -04:00
Mike Chan 00e299fff3 [CPUFREQ] ondemand: Refactor frequency increase code
Make simpler to read and call.

*** v3 - Always call when powersave_bias is enabled.

Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Mike Chan <mike@android.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2010-08-03 13:47:04 -04:00
Linus Torvalds 07d77759c9 Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, hypervisor: add missing <linux/module.h>
  Modify the VMware balloon driver for the new x86_hyper API
  x86, hypervisor: Export the x86_hyper* symbols
  x86: Clean up the hypervisor layer
  x86, HyperV: fix up the license to mshyperv.c
  x86: Detect running on a Microsoft HyperV system
  x86, cpu: Make APERF/MPERF a normal table-driven flag
  x86, k8: Fix build error when K8_NB is disabled
  x86, cacheinfo: Disable index in all four subcaches
  x86, cacheinfo: Make L3 cache info per node
  x86, cacheinfo: Reorganize AMD L3 cache structure
  x86, cacheinfo: Turn off L3 cache index disable feature in virtualized environments
  x86, cacheinfo: Unify AMD L3 cache index disable checking
  cpufreq: Unify sysfs attribute definition macros
  powernow-k8: Fix frequency reporting
  x86, cpufreq: Add APERF/MPERF support for AMD processors
  x86: Unify APERF/MPERF support
  powernow-k8: Add core performance boost support
  x86, cpu: Add AMD core boosting feature flag to /proc/cpuinfo

Fix up trivial conflicts in arch/x86/kernel/cpu/intel_cacheinfo.c and
drivers/cpufreq/cpufreq_ondemand.c
2010-05-18 08:49:13 -07:00
Arjan van de Ven 19379b1181 ondemand: Make the iowait-is-busy time a sysfs tunable
Pavel Machek pointed out that not all CPUs have an efficient
idle at high frequency. Specifically, older Intel and various
AMD cpus would get a higher powerusage when copying files from
USB.

Mike Chan pointed out that the same is true for various ARM
chips as well.

Thomas Renninger suggested to make this a sysfs tunable with a
reasonable default.

This patch adds a sysfs tunable for the new behavior, and uses
a very simple function to determine a reasonable default,
depending on the CPU vendor/type.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
LKML-Reference: <20100509082651.46914d04@infradead.org>
[ minor tidyup ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-09 19:35:27 +02:00
Arjan van de Ven 6b8fcd9029 ondemand: Solve a big performance issue by counting IOWAIT time as busy
The ondemand cpufreq governor uses CPU busy time (e.g. not-idle
time) as a measure for scaling the CPU frequency up or down.
If the CPU is busy, the CPU frequency scales up, if it's idle,
the CPU frequency scales down. Effectively, it uses the CPU busy
time as proxy variable for the more nebulous "how critical is
performance right now" question.

This algorithm falls flat on its face in the light of workloads
where you're alternatingly disk and CPU bound, such as the ever
popular "git grep", but also things like startup of programs and
maildir using email clients... much to the chagarin of Andrew
Morton.

This patch changes the ondemand algorithm to count iowait time
as busy, not idle, time. As shown in the breakdown cases above,
iowait is performance critical often, and by counting iowait,
the proxy variable becomes a more accurate representation of the
"how critical is performance" question.

The problem and fix are both verified with the "perf timechar"
tool.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100509082606.3d9f00d0@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-09 19:35:27 +02:00