Re: [PATCH v5 1/4] PM: Add a sysfs file to represent time spent in hardware sleep state

[Rafael J. Wysocki]

On Fri, Mar 31, 2023 at 8:05 PM Limonciello, Mario
<mario.limonciello@xxxxxxx> wrote:
>
> On 3/31/2023 13:01, Rafael J. Wysocki wrote:
> > On Thu, Mar 30, 2023 at 9:45 PM Mario Limonciello
> > <mario.limonciello@xxxxxxx> wrote:
> >>
> >> Userspace can't easily discover how much of a sleep cycle was spent in a
> >> hardware sleep state without using kernel tracing and vendor specific sysfs
> >> or debugfs files.
> >>
> >> To make this information more discoverable, introduce a new sysfs file
> >> to represent the time spent in a sleep state.
> >
> > This is only in the most recent suspend-resume cycle, isn't it?
>
> Yes; that's correct.
>
> >
> > Wouldn't it be useful to have another attribute printing the
> > accumulated total HW sleep time?
> >
>
> I had considered this; but I didn't think it was actually very useful
> because userspace will get control at the end of every cycle and can
> accumulate those numbers if desirable.

Unless "user space" in question is actually a human, that is.