From: Viresh Kumar <viresh.kumar@linaro.org>
To: Steve Muckle <steve.muckle@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Juri Lelli <Juri.Lelli@arm.com>,
Patrick Bellasi <patrick.bellasi@arm.com>,
Michael Turquette <mturquette@baylibre.com>
Subject: Re: [PATCH v2 1/3] cpufreq: add resolve_freq driver callback
Date: Tue, 31 May 2016 11:00:11 +0530 [thread overview]
Message-ID: <20160531053011.GD9463@vireshk-i7> (raw)
In-Reply-To: <20160530153115.GE9864@graphite.smuckle.net>
On 30-05-16, 08:31, Steve Muckle wrote:
> My goal here was to have the system operate in this case in a manner
> that is obviously not optimized (running at fmax), so the platform owner
> realizes that the cpufreq driver doesn't fully support the schedutil
> governor.
>
> I was originally going to just return an error code but that also means
> having to check for it which would be nice to avoid if possible on this
> fast path.
Okay, I get what you are saying.
But all we are doing here is to make things fast by not sending IPIs,
etc. That should *not* lead to a behavior where the frequency stays at
MAX all the time even if the driver doesn't provide this callback or
the freq-table.
If we just return the target_freq in this case instead of UINT_MAX,
the platform may eventually have some unnecessary IPIs, wakeups, etc,
but its frequency will still be switched properly.
Wouldn't that be a better choice ?
--
viresh
next prev parent reply other threads:[~2016-05-31 5:30 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-26 2:52 [PATCH v2 0/3] cpufreq: avoid redundant driver calls in schedutil Steve Muckle
2016-05-26 2:52 ` [PATCH v2 1/3] cpufreq: add resolve_freq driver callback Steve Muckle
2016-05-26 6:25 ` Viresh Kumar
2016-05-30 15:31 ` Steve Muckle
2016-05-31 5:30 ` Viresh Kumar [this message]
2016-05-31 18:48 ` Steve Muckle
2016-05-31 11:14 ` Viresh Kumar
2016-05-31 18:12 ` Steve Muckle
2016-05-26 2:53 ` [PATCH v2 2/3] cpufreq: acpi-cpufreq: add resolve_freq callback Steve Muckle
2016-05-26 6:43 ` Viresh Kumar
2016-05-30 16:20 ` Steve Muckle
2016-05-31 11:38 ` Viresh Kumar
2016-05-26 2:53 ` [PATCH v2 3/3] cpufreq: schedutil: map raw required frequency to driver frequency Steve Muckle
2016-05-26 7:16 ` Viresh Kumar
2016-05-29 0:40 ` Rafael J. Wysocki
2016-05-30 10:18 ` Viresh Kumar
2016-05-30 14:25 ` Rafael J. Wysocki
2016-05-30 15:32 ` Viresh Kumar
2016-05-30 19:08 ` Rafael J. Wysocki
2016-05-31 9:02 ` Peter Zijlstra
2016-05-31 1:49 ` Wanpeng Li
2016-05-30 16:35 ` Steve Muckle
2016-06-01 10:50 ` Viresh Kumar
2016-05-27 5:41 ` Wanpeng Li
2016-05-30 16:48 ` Steve Muckle
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