From: Matthias Kaehlcke <mka@chromium.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
Kevin Hilman <khilman@kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@redhat.com>,
Douglas Anderson <dianders@chromium.org>,
linux-pm@vger.kernel.org,
Amit Kucheria <amit.kucheria@linaro.org>,
linux-kernel@vger.kernel.org,
Ravi Chandra Sadineni <ravisadineni@chromium.org>
Subject: Re: [PATCH v1] PM / Domains: Add tracepoints
Date: Tue, 1 Oct 2019 10:42:35 -0700 [thread overview]
Message-ID: <20191001174235.GC87296@google.com> (raw)
In-Reply-To: <20191001130343.4480afe3@gandalf.local.home>
On Tue, Oct 01, 2019 at 01:03:43PM -0400, Steven Rostedt wrote:
> On Tue, 1 Oct 2019 09:35:42 -0700
> Matthias Kaehlcke <mka@chromium.org> wrote:
>
> > How about this instead:
> >
> > Add tracepoints for genpd_power_on, genpd_power_off and
> > genpd_set_performance_state. The tracepoints can help with
> > understanding power domain behavior of a given device, which
> > may be particularly interesting for battery powered devices
> > and suspend/resume.
>
> Do you have a use case example to present?
TBH I'm not looking into a specific use case right now. While
peeking around in /sys/kernel/debug/tracing/events to learn more
about existing tracepoints that might be relevant for my work
I noticed the absence of genpd ones and it seemed a good idea to
add them preemptively. Conceptually they seem similar to the
existing regulator_enable/disable and cpu_idle tracepoints.
As an abstract use case I could see power analysis on battery
powered devices during suspend. genpd_power_on/off allow to see
which power domains remain on during suspend, and might give
insights for possible power saving options. Examples could be that
a power domain stays unexpectedly on due to a misconfiguration, or
two power domains remain on when it could be only one if you just
moved that one pin/port over to the other domain in the next
hardware revision.
next prev parent reply other threads:[~2019-10-01 17:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 22:04 [PATCH v1] PM / Domains: Add tracepoints Matthias Kaehlcke
2019-09-27 5:36 ` Greg Kroah-Hartman
2019-09-27 8:42 ` Steven Rostedt
2019-10-01 16:35 ` Matthias Kaehlcke
2019-10-01 17:03 ` Steven Rostedt
2019-10-01 17:42 ` Matthias Kaehlcke [this message]
2019-10-01 18:08 ` Steven Rostedt
2019-10-01 19:37 ` Matthias Kaehlcke
2019-10-02 7:55 ` Rafael J. Wysocki
2019-10-02 19:10 ` Pavel Machek
2019-10-15 12:37 ` Ulf Hansson
2019-10-15 17:19 ` Matthias Kaehlcke
2019-10-16 13:47 ` Ulf Hansson
2019-10-16 18:13 ` Matthias Kaehlcke
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