[PATCH 2/2] n2100: reduce power button timer to 1 Hz
Mikael Pettersson
mikpe at it.uu.se
Mon Sep 28 07:26:48 EDT 2009
Aaro Koskinen writes:
> Hello,
>
> Mikael Pettersson wrote:
> > Aaro Koskinen writes:
> > > Mikael Pettersson wrote:
> > > > 10 Hz seems excessive, so this patch adds a compile-time option
> > > > to reduce the polling frequency to 1 Hz.
> > > >
> > > > (This change could possibly be handled via a kernel boot option,
> > > > or even be made unconditional, but I opted for a compile-time
> > > > option for now.)
> > >
> > > I don't think there is need to have an option for this. With HZ also
> > > round_jiffies() could be used, it doesn't need to be exact.
> >
> > I don't quite follow you here. Can you elaborate?
>
> round_jiffies() rounds the time up or down to a full second. It's useful for
> timers that expire every N seconds. This way timeouts can be grouped, so there
> is less wakeups.
Ah, the two sentences were not to be taken as a group:
1) no need for an option, i.e. reduce to 1 Hz unconditionally, and
2) with a 1 Hz timer, use round_jiffies() in the hope of grouping
with other whole-Hz timers that also use round_jiffies().
I'll look into using round_jiffies().
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