Messages in this thread | | | Date | Wed, 16 Oct 2019 11:13:17 -0700 | From | Matthias Kaehlcke <> | Subject | Re: [PATCH v1] PM / Domains: Add tracepoints |
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On Wed, Oct 16, 2019 at 03:47:44PM +0200, Ulf Hansson wrote: > On Tue, 15 Oct 2019 at 19:19, Matthias Kaehlcke <mka@chromium.org> wrote: > > > > Hi Ulf, > > > > On Tue, Oct 15, 2019 at 02:37:42PM +0200, Ulf Hansson wrote: > > > On Tue, 1 Oct 2019 at 18:35, Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > On Fri, Sep 27, 2019 at 04:42:39AM -0400, Steven Rostedt wrote: > > > > > On Thu, 26 Sep 2019 15:04:38 -0700 > > > > > Matthias Kaehlcke <mka@chromium.org> wrote: > > > > > > > > > > > Define genpd_power_on/off and genpd_set_performance_state > > > > > > tracepoints and use them. > > > > > > > > > > I agree with Greg about adding a "why" you need this. But, in case > > > > > there's a good reason to have this, I have comments about the code > > > > > below. > > > > > > > > Thanks Greg and Steven for your comments. > > > > > > > > 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. > > > > > > Apologize for the delay, no excuse! > > > > > > I don't mind adding trace events, as long as it's for good reasons - > > > and to me, that seems a bit questionable here. > > > > > > According to the above, I believe the information you need is already > > > available via genpd's debugfs interface, no? > > > > Not in all cases, e.g. you can't peek at sysfs while the device is > > suspended. > > Not sure I get this right. If a device that is attached to a genpd > that is runtime suspended, for sure you can have a look at the genpd > debugfs to see its current status.
Sorry, I used an ambiguous terminology by talking about 'the device', I was referring to system suspend.
> > Also sysfs doesn't help much with seeing that a PD is > > toggling between on an off for some (possibly legitimate) reason. > > Well, you could look at the "active_time" and the "total_idle_time" > nodes for the genpd in question. Those should change accordingly.
Ok, thanks for the pointer!
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