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Message-ID: <20190919172533.GS133864@google.com>
Date: Thu, 19 Sep 2019 10:25:33 -0700
From: Matthias Kaehlcke <mka@...omium.org>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: MyungJoo Ham <myungjoo.ham@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
Chanwoo Choi <cw00.choi@...sung.com>,
Ingo Molnar <mingo@...hat.com>, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org,
Douglas Anderson <dianders@...omium.org>
Subject: Re: [PATCH] devfreq: Add tracepoint for frequency changes
On Thu, Sep 19, 2019 at 12:35:59PM -0400, Steven Rostedt wrote:
> On Wed, 18 Sep 2019 12:15:37 -0700
> Matthias Kaehlcke <mka@...omium.org> wrote:
>
> > Add a tracepoint for frequency changes of devfreq devices and
> > use it.
> >
> > Signed-off-by: Matthias Kaehlcke <mka@...omium.org>
> > ---
> > drivers/devfreq/devfreq.c | 3 +++
> > include/trace/events/devfreq.h | 18 ++++++++++++++++++
> > 2 files changed, 21 insertions(+)
> >
> > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> > index ab22bf8a12d6..32de1f6ac776 100644
> > --- a/drivers/devfreq/devfreq.c
> > +++ b/drivers/devfreq/devfreq.c
> > @@ -317,6 +317,9 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
> >
> > devfreq->previous_freq = new_freq;
> >
> > + if (new_freq != cur_freq)
>
> I would make this:
>
> if (trace_devfreq_frequency_enabled() && new_freq != cur_freq)
>
> Because this would place the second check into the "nop" portion of the
> code, keeping the test from being performed if the devfreq_frequency
> trace point is not enabled. Slight micro optimization, but still enough
> to add it.
Sounds good to me, thanks for the review!
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