From: "Doug Smythies" <dsmythies@telus.net>
To: "'Viresh Kumar'" <viresh.kumar@linaro.org>,
"'Rafael Wysocki'" <rjw@rjwysocki.net>,
"'Ingo Molnar'" <mingo@redhat.com>,
"'Peter Zijlstra'" <peterz@infradead.org>
Cc: <linux-pm@vger.kernel.org>,
"'Vincent Guittot'" <vincent.guittot@linaro.org>,
<joel@joelfernandes.org>, "'v4 . 18+'" <stable@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] cpufreq: schedutil: Don't skip freq update when limits change
Date: Tue, 23 Jul 2019 00:10:01 -0700 [thread overview]
Message-ID: <001201d54125$a6a82350$f3f869f0$@net> (raw)
In-Reply-To: <8091ef83f264feb2feaa827fbeefe08348bcd05d.1563778071.git.viresh.kumar@linaro.org>
On 2019.07.21 23:52 Viresh Kumar wrote:
> To avoid reducing the frequency of a CPU prematurely, we skip reducing
> the frequency if the CPU had been busy recently.
>
> This should not be done when the limits of the policy are changed, for
> example due to thermal throttling. We should always get the frequency
> within limits as soon as possible.
>
> Fixes: ecd288429126 ("cpufreq: schedutil: Don't set next_freq to UINT_MAX")
> Cc: v4.18+ <stable@vger.kernel.org> # v4.18+
> Reported-by: Doug Smythies <doug.smythies@gmail.com>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> @Doug: Please try this patch, it must fix the issue you reported.
It fixes the driver = acpi-cpufreq ; governor = schedutil test case
It does not fix the driver = intel_cpufreq ; governor = schedutil test case
I have checked my results twice, but will check again in the day or two.
... Doug
>
> kernel/sched/cpufreq_schedutil.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index 636ca6f88c8e..b53c4f02b0f1 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -447,7 +447,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
> struct sugov_policy *sg_policy = sg_cpu->sg_policy;
> unsigned long util, max;
> unsigned int next_f;
> - bool busy;
> + bool busy = false;
>
> sugov_iowait_boost(sg_cpu, time, flags);
> sg_cpu->last_update = time;
> @@ -457,7 +457,9 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
> if (!sugov_should_update_freq(sg_policy, time))
> return;
>
> - busy = sugov_cpu_is_busy(sg_cpu);
> + /* Limits may have changed, don't skip frequency update */
> + if (!sg_policy->need_freq_update)
> + busy = sugov_cpu_is_busy(sg_cpu);
>
> util = sugov_get_util(sg_cpu);
> max = sg_cpu->max;
> --
> 2.21.0.rc0.269.g1a574e7a288b
next prev parent reply other threads:[~2019-07-23 7:10 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-18 6:26 [PATCH] Revert "cpufreq: schedutil: Don't set next_freq to UINT_MAX" Doug Smythies
2019-07-18 10:28 ` Viresh Kumar
2019-07-18 15:46 ` Doug Smythies
2019-07-22 6:49 ` Viresh Kumar
2019-07-22 6:51 ` [PATCH] cpufreq: schedutil: Don't skip freq update when limits change Viresh Kumar
2019-07-23 7:10 ` Doug Smythies [this message]
2019-07-23 9:13 ` Rafael J. Wysocki
2019-07-23 9:15 ` Viresh Kumar
2019-07-23 10:27 ` Rafael J. Wysocki
2019-07-24 11:43 ` Viresh Kumar
2019-07-25 15:20 ` Doug Smythies
2019-07-26 3:26 ` Viresh Kumar
2019-07-26 6:57 ` Viresh Kumar
2019-07-29 7:55 ` Doug Smythies
2019-07-29 8:32 ` Viresh Kumar
2019-07-29 8:37 ` Rafael J. Wysocki
2019-08-01 0:20 ` Doug Smythies
2019-08-01 6:17 ` Viresh Kumar
2019-08-01 7:47 ` Rafael J. Wysocki
2019-08-01 7:55 ` Viresh Kumar
2019-08-01 17:57 ` Doug Smythies
2019-08-02 3:48 ` Viresh Kumar
2019-08-02 9:11 ` Rafael J. Wysocki
2019-08-02 9:19 ` Rafael J. Wysocki
2019-08-06 4:00 ` Viresh Kumar
2019-07-31 2:58 Viresh Kumar
2019-07-31 23:19 ` Doug Smythies
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