On Tue, 1 Oct 2019 10:42:35 -0700 Matthias Kaehlcke <m...@chromium.org> wrote:
> On Tue, Oct 01, 2019 at 01:03:43PM -0400, Steven Rostedt wrote: > > On Tue, 1 Oct 2019 09:35:42 -0700 > > Matthias Kaehlcke <m...@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. If the power management maintainers have no issues with adding these, then neither do I ;-) It would be them who would pull them in anyway. -- Steve
