Messages in this thread | | | Date | Tue, 1 Oct 2019 10:42:35 -0700 | From | Matthias Kaehlcke <> | Subject | Re: [PATCH v1] PM / Domains: Add tracepoints |
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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.
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