From: Viresh Kumar <viresh.kumar@linaro.org>
To: Matthias Kaehlcke <mka@chromium.org>
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Viresh Kumar <vireshk@kernel.org>,
linux-pm@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] drivers: base: Add frequency constraint infrastructure
Date: Tue, 22 Jan 2019 12:39:36 +0530 [thread overview]
Message-ID: <20190122070936.jsjvivzplfpdweck@vireshk-i7> (raw)
In-Reply-To: <20190118224534.GC261387@google.com>
On 18-01-19, 14:45, Matthias Kaehlcke wrote:
> On Fri, Jan 18, 2019 at 03:32:34PM +0530, Viresh Kumar wrote:
> > On 17-01-19, 17:03, Matthias Kaehlcke wrote:
> > > On Fri, Jan 11, 2019 at 02:48:34PM +0530, Viresh Kumar wrote:
> > > > +static void fcs_update(struct freq_constraints *fcs, struct freq_pair *freq,
> > > > + enum fc_event event)
> > > > +{
> > > > + mutex_lock(&fcs->lock);
> > > > +
> > > > + if (_fcs_update(fcs, freq, event)) {
> > > > + if (fcs->callback)
> > > > + schedule_work(&fcs->work);
> > >
> > > IIUC the constraints aren't applied until the callback is executed. I
> > > wonder if a dedicated workqueue should be used instead of the system
> > > one, to avoid longer delays from other kernel entities that might
> > > 'misbehave'. Especially for thermal constraints we want a quick
> > > response.
> >
> > I thought the system workqueue should be fast enough, it contains
> > multiple threads which can all run in parallel and service this work.
>
> Ok, I was still stuck at the old one thread per CPU model, where a
> slow work would block other items in the same workqueue until it
> finishes execution. After reading a bit through
> Documentation/core-api/workqueue.rst I agree that a system workqueue
> is probably fast enough. It might be warranted though to use
> system_highpri_wq here.
Is this really that high priority stuff ? I am not sure.
--
viresh
next prev parent reply other threads:[~2019-01-22 7:09 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-11 9:18 [PATCH 0/3] drivers: Frequency constraint infrastructure Viresh Kumar
2019-01-11 9:18 ` [PATCH 1/3] drivers: base: Add frequency " Viresh Kumar
2019-01-18 1:03 ` Matthias Kaehlcke
2019-01-18 10:02 ` Viresh Kumar
2019-01-18 22:45 ` Matthias Kaehlcke
2019-01-22 7:09 ` Viresh Kumar [this message]
2019-01-22 17:50 ` Matthias Kaehlcke
2019-01-11 9:18 ` [PATCH 2/3] cpufreq: Implement freq-constraint callback Viresh Kumar
2019-01-18 1:46 ` Matthias Kaehlcke
2019-01-18 1:49 ` Matthias Kaehlcke
2019-01-11 9:18 ` [PATCH 3/3] cpufreq: Implement USER constraint Viresh Kumar
2019-01-11 9:47 ` [PATCH 0/3] drivers: Frequency constraint infrastructure Rafael J. Wysocki
2019-01-17 13:16 ` Juri Lelli
2019-01-17 14:55 ` Rafael J. Wysocki
2019-01-18 12:39 ` Juri Lelli
2019-01-21 11:10 ` Rafael J. Wysocki
2019-01-22 19:30 ` Matthias Kaehlcke
[not found] ` <CA+mqd+7EqERei8eekAsVxa_bJUYETyO3T76L8Q_sV=C9rwiy3g@mail.gmail.com>
2019-01-28 14:04 ` Qais Yousef
2019-01-30 5:27 ` Viresh Kumar
2019-01-30 5:25 ` Viresh Kumar
2019-02-08 9:08 ` Viresh Kumar
2019-02-08 9:09 ` Viresh Kumar
2019-02-08 9:53 ` Rafael J. Wysocki
2019-02-08 10:23 ` Viresh Kumar
2019-02-08 10:35 ` Rafael J. Wysocki
2019-02-11 5:43 ` Viresh Kumar
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