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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Rafael Wysocki <rjw@rjwysocki.net>,
	Ben Segall <bsegall@google.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>, Mel Gorman <mgorman@suse.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-pm@vger.kernel.org, Lukasz Luba <lukasz.luba@arm.com>,
	cristian.marussi@arm.com, sudeep.holla@arm.com,
	linux-kernel@vger.kernel.org
Subject: [PATCH V2 0/4] cpufreq: Record stats with fast-switching
Date: Wed, 16 Sep 2020 12:15:27 +0530	[thread overview]
Message-ID: <cover.1600238586.git.viresh.kumar@linaro.org> (raw)

Hi,

We disabled recording cpufreq stats when fast switching was introduced
to the cpufreq core as the cpufreq stats required to take a spinlock and
that can't be allowed (for performance reasons) on scheduler's hot path.

Here is an attempt to get rid of the lock and bring back the support.

V1-V2:
- Use READ_ONCE/WRITE_ONCE instead of atomic in the first patch.

--
Viresh

Viresh Kumar (4):
  cpufreq: stats: Defer stats update to
    cpufreq_stats_record_transition()
  cpufreq: stats: Remove locking
  cpufreq: stats: Enable stats for fast-switch as well
  cpufreq: Move traces and update to policy->cur to cpufreq core

 drivers/cpufreq/cpufreq.c        | 16 +++++-
 drivers/cpufreq/cpufreq_stats.c  | 87 ++++++++++++++++++++------------
 kernel/sched/cpufreq_schedutil.c | 12 +----
 3 files changed, 72 insertions(+), 43 deletions(-)


base-commit: 856deb866d16e29bd65952e0289066f6078af773
-- 
2.25.0.rc1.19.g042ed3e048af


             reply	other threads:[~2020-09-16  6:45 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-16  6:45 Viresh Kumar [this message]
2020-09-16  6:45 ` [PATCH V2 1/4] cpufreq: stats: Defer stats update to cpufreq_stats_record_transition() Viresh Kumar
2020-09-23 13:48   ` Rafael J. Wysocki
2020-09-24  9:25     ` Lukasz Luba
2020-09-24 10:24       ` Rafael J. Wysocki
2020-09-24 11:00         ` Lukasz Luba
2020-09-24 11:07           ` Rafael J. Wysocki
2020-09-24 12:39             ` Viresh Kumar
2020-09-24 16:10               ` Lukasz Luba
2020-09-25  6:09                 ` Viresh Kumar
2020-09-25  8:10                   ` Lukasz Luba
2020-09-24 13:15     ` Viresh Kumar
2020-09-25 10:04       ` Rafael J. Wysocki
2020-09-25 10:58         ` Viresh Kumar
2020-09-25 11:09           ` Rafael J. Wysocki
2020-09-25 11:26             ` Viresh Kumar
2020-09-25  8:21   ` Lukasz Luba
2020-09-25 10:46     ` Viresh Kumar
2020-09-16  6:45 ` [PATCH V2 2/4] cpufreq: stats: Remove locking Viresh Kumar
2020-09-16  6:45 ` [PATCH V2 3/4] cpufreq: stats: Enable stats for fast-switch as well Viresh Kumar
2020-09-23 15:14   ` Rafael J. Wysocki
2020-09-23 15:17     ` Rafael J. Wysocki
2020-09-16  6:45 ` [PATCH V2 4/4] cpufreq: Move traces and update to policy->cur to cpufreq core Viresh Kumar

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