lkml.org 
[lkml]   [2009]   [Feb]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC] Dynamic Tick and Deferrable Timer Support
On Thu 2009-01-29 09:36:00, john stultz wrote:
> On Thu, Jan 29, 2009 at 8:29 AM, Jon Hunter <jon-hunter@ti.com> wrote:
> > Pallipadi, Venkatesh wrote:
> > I have spent several weeks trying to suppress kernel timers using the
> > deferred timers and lengthen the sleep time. I am now able to get the device
> > to sleep for minutes but I found that max_delta_ns is a limiting factor. I
> > will be surprised if you can sleep for longer than ~2.15 seconds with the
> > current implementation.
>
> As an aside, there are some further hardware limitations in the
> timekeeping core that limit the amount of time the hardware can sleep.
> For instance, the acpi_pm clocksource wraps every 2.5 seconds or so,
> so we have to wake up periodically to sample it to avoid wrapping
> issues.
>
> Just to be able to deal with all the different hardware out there, the
> timekeeping core expects to wake up twice a second to do this
> sampling. It may be possible to push this out if you are using other

That's strange... I think I seen less than 2 wakeups per second on
powertop...? (thinkpad x60, nothing exotic).
Pavel

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


\
 
 \ /
  Last update: 2009-02-07 10:25    [W:0.101 / U:0.284 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site