From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Wei Wang <wvw@google.com>
Cc: Wei Wang <wei.vince.wang@gmail.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Quentin Perret <qperret@google.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Linux PM <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched: cpufreq_schedutil: restore cached freq when next_f is not changed
Date: Mon, 19 Oct 2020 17:39:50 +0200 [thread overview]
Message-ID: <CAJZ5v0jaftAQv9-=5YucNnm__Z7NWRWmN2mCO07i0ZhV9K5EsQ@mail.gmail.com> (raw)
In-Reply-To: <20201016181722.884812-1-wvw@google.com>
On Fri, Oct 16, 2020 at 8:17 PM Wei Wang <wvw@google.com> wrote:
>
> We have the raw cached freq to reduce the chance in calling cpufreq
> driver where it could be costly in some arch/SoC.
>
> Currently, the raw cached freq will be reset when next_f is changed for
> correctness. This patch changes it to maintain the cached value instead
> of dropping it to honor the purpose of the cached value.
>
> This is adapted from https://android-review.googlesource.com/1352810/
>
> Signed-off-by: Wei Wang <wvw@google.com>
> ---
> kernel/sched/cpufreq_schedutil.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index 5ae7b4e6e8d6..e254745a82cb 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -441,6 +441,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
> unsigned long util, max;
> unsigned int next_f;
> bool busy;
> + unsigned int cached_freq = sg_policy->cached_raw_freq;
>
> sugov_iowait_boost(sg_cpu, time, flags);
> sg_cpu->last_update = time;
> @@ -464,8 +465,8 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
> if (busy && next_f < sg_policy->next_freq) {
> next_f = sg_policy->next_freq;
>
> - /* Reset cached freq as next_freq has changed */
> - sg_policy->cached_raw_freq = 0;
> + /* Restore cached freq as next_freq has changed */
> + sg_policy->cached_raw_freq = cached_freq;
> }
>
> /*
> --
Applied as 5.10-rc material with edited subject and rewritten changelog.
Thanks!
prev parent reply other threads:[~2020-10-19 15:40 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-16 16:36 [PATCH] sched: cpufreq_schedutil: maintain raw cache when next_f is not changed Wei Wang
2020-10-16 17:01 ` Rafael J. Wysocki
2020-10-16 17:17 ` Wei Wang
2020-10-16 17:36 ` Rafael J. Wysocki
2020-10-16 17:48 ` Wei Wang
2020-10-16 18:17 ` [PATCH] sched: cpufreq_schedutil: restore cached freq " Wei Wang
2020-10-19 5:09 ` Viresh Kumar
2020-10-19 15:39 ` Rafael J. Wysocki [this message]
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