From: Valentin Schneider <valentin.schneider@arm.com>
To: Benjamin GAIGNARD <benjamin.gaignard@st.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"viresh.kumar\@linaro.org" <viresh.kumar@linaro.org>,
Hugues FRUCHET <hugues.fruchet@st.com>,
"mchehab\@kernel.org" <mchehab@kernel.org>,
"mcoquelin.stm32\@gmail.com" <mcoquelin.stm32@gmail.com>,
Alexandre TORGUE <alexandre.torgue@st.com>,
"pavel\@ucw.cz" <pavel@ucw.cz>,
"len.brown\@intel.com" <len.brown@intel.com>,
"linux-pm\@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-media\@vger.kernel.org" <linux-media@vger.kernel.org>,
"linux-stm32\@st-md-mailman.stormreply.com"
<linux-stm32@st-md-mailman.stormreply.com>,
"linux-arm-kernel\@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Patrick Bellasi <patrick.bellasi@arm.com>
Subject: Re: [RFC 0/3] Introduce cpufreq minimum load QoS
Date: Thu, 30 Apr 2020 15:33:35 +0100 [thread overview]
Message-ID: <jhjtv11cabk.mognet@arm.com> (raw)
In-Reply-To: <a234e123-6c15-8e58-8921-614b58ca24ca@st.com>
On 30/04/20 14:46, Benjamin GAIGNARD wrote:
>> That's not what I meant.
>>
>> I suppose that the interrupt processing in question takes place in
>> process context and so you may set the lower clamp on the utilization
>> of the task carrying that out.
>
> I have try to add this code when starting streaming (before the first
> interrupt) the frames from the sensor:
> const struct sched_attr sched_attr = {
> .sched_util_min = 10000, /* 100% of usage */
Unless you play with SCHED_CAPACITY_SHIFT, the max should be 1024 -
i.e. SCHED_CAPACITY_SCALE. That's a really big boost, but that's for you to
benchmark.
> .sched_flags = SCHED_FLAG_UTIL_CLAMP_MIN,
> };
>
> sched_setattr(current, &sched_attr);
>
> I don't see any benefices maybe there is some configuration flags to set.
>
> How changing sched_util_min could impact cpufreq ondemand governor ?
> Does it change the value returned when the governor check the idle time ?
>
You'll have to use the schedutil governor for uclamp to have an effect. And
arguably that's what you should be using, unless something explicitly
prevents you from doing that.
>>
>> Alternatively, that task may be a deadline one.
next prev parent reply other threads:[~2020-04-30 14:33 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-24 11:40 [RFC 0/3] Introduce cpufreq minimum load QoS Benjamin Gaignard
2020-04-24 11:40 ` [RFC 1/3] PM: QoS: " Benjamin Gaignard
2020-04-24 11:40 ` [RFC 2/3] cpufreq: governor: Use " Benjamin Gaignard
2020-04-24 11:40 ` [RFC 3/3] media: stm32-dcmi: Inform cpufreq governors about cpu load needs Benjamin Gaignard
2020-04-29 15:50 ` [RFC 0/3] Introduce cpufreq minimum load QoS Rafael J. Wysocki
2020-04-29 15:57 ` Benjamin GAIGNARD
2020-04-29 16:12 ` Valentin Schneider
2020-04-30 7:52 ` Benjamin GAIGNARD
2020-04-30 9:03 ` Rafael J. Wysocki
2020-04-30 13:46 ` Benjamin GAIGNARD
2020-04-30 14:33 ` Valentin Schneider [this message]
2020-04-30 15:37 ` Benjamin GAIGNARD
2020-04-30 15:50 ` Valentin Schneider
2020-05-04 9:17 ` Benjamin GAIGNARD
2020-05-20 7:29 ` [Linux-stm32] " Benjamin GAIGNARD
2020-04-29 17:08 ` Vincent Guittot
2020-04-30 9:00 ` Rafael J. Wysocki
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