From: Patrick Bellasi <patrick.bellasi@arm.com>
To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Cc: Patrick Bellasi <patrick.bellasi@arm.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Steven Rostedt <rostedt@goodmis.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
John Stultz <john.stultz@linaro.org>,
Juri Lelli <juri.lelli@arm.com>, Todd Kjos <tkjos@android.com>,
Tim Murray <timmurray@google.com>,
Andres Oportus <andresoportus@google.com>,
Joel Fernandes <joelaf@google.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Chris Redpath <chris.redpath@arm.com>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Subject: [PATCH 2/6] cpufreq: schedutil: ignore the sugov kthread for frequencies selections
Date: Thu, 2 Mar 2017 15:45:03 +0000 [thread overview]
Message-ID: <1488469507-32463-3-git-send-email-patrick.bellasi@arm.com> (raw)
In-Reply-To: <1488469507-32463-1-git-send-email-patrick.bellasi@arm.com>
In system where multiple CPUs shares the same frequency domain a small
workload on a CPU can still be subject frequency spikes, generated by
the activation of the sugov's kthread.
Since the sugov kthread is a special RT task, which goal is just that to
activate a frequency transition, it does not make sense for it to bias
the schedutil's frequency selection.
This patch exploits the information related to the current task to silently
ignore cpufreq_update_this_cpu() calls, coming from the RT scheduler, while
the sugov kthread is running.
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
---
kernel/sched/cpufreq_schedutil.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 084a98b..a3fe5e4 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -274,6 +274,8 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
{
struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+ unsigned int cpu = smp_processor_id();
+ struct task_struct *curr = cpu_curr(cpu);
unsigned long util, max;
unsigned int next_f;
@@ -287,6 +289,10 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
goto done;
}
+ /* Skip updates generated by sugov kthreads */
+ if (curr == sg_policy->thread)
+ goto done;
+
sg_cpu->util = util;
sg_cpu->max = max;
sg_cpu->flags = flags;
--
2.7.4
next prev parent reply other threads:[~2017-03-02 15:49 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-02 15:45 [PATCH 0/6] cpufreq: schedutil: fixes for flags updates Patrick Bellasi
2017-03-02 15:45 ` [PATCH 1/6] cpufreq: schedutil: reset sg_cpus's flags at IDLE enter Patrick Bellasi
2017-03-03 3:41 ` Viresh Kumar
2017-03-06 14:29 ` Steven Rostedt
2017-03-15 18:06 ` Patrick Bellasi
2017-03-28 22:18 ` Rafael J. Wysocki
2017-04-07 14:59 ` Patrick Bellasi
2017-06-06 9:26 ` Viresh Kumar
2017-06-06 15:56 ` Rafael J. Wysocki
2017-06-06 18:03 ` Patrick Bellasi
2017-03-02 15:45 ` Patrick Bellasi [this message]
2017-03-03 5:19 ` [PATCH 2/6] cpufreq: schedutil: ignore the sugov kthread for frequencies selections Viresh Kumar
2017-03-03 12:12 ` Patrick Bellasi
2017-03-06 5:08 ` Viresh Kumar
2017-03-06 14:35 ` Steven Rostedt
2017-03-15 18:02 ` Patrick Bellasi
2017-03-02 15:45 ` [PATCH 3/6] cpufreq: schedutil: ensure max frequency while running RT/DL tasks Patrick Bellasi
2017-03-03 8:31 ` Viresh Kumar
2017-03-03 12:38 ` Patrick Bellasi
2017-03-15 11:52 ` Rafael J. Wysocki
2017-03-15 14:40 ` Patrick Bellasi
2017-03-15 23:32 ` Rafael J. Wysocki
2017-03-17 11:36 ` Patrick Bellasi
2017-04-07 15:30 ` Peter Zijlstra
2017-04-07 16:59 ` Patrick Bellasi
2017-03-02 15:45 ` [PATCH 4/6] cpufreq: schedutil: relax rate-limiting " Patrick Bellasi
2017-03-02 15:45 ` [PATCH 5/6] cpufreq: schedutil: avoid utilisation update when not necessary Patrick Bellasi
2017-03-02 15:45 ` [PATCH 6/6] sched/rt: fast switch to maximum frequency when RT tasks are scheduled Patrick Bellasi
2017-03-02 16:09 ` [PATCH 0/6] cpufreq: schedutil: fixes for flags updates Vincent Guittot
2017-03-02 17:11 ` Patrick Bellasi
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