Re: A few questions and issues with dynticks, NOHZ and powertop
From: Dominik Brodowski
Date: Mon Apr 05 2010 - 16:42:44 EST
On Sun, Apr 04, 2010 at 08:42:43PM -0700, Arjan van de Ven wrote:
> On 4/4/2010 3:47, Dominik Brodowski wrote:
> >On Sat, Apr 03, 2010 at 04:53:26PM -0700, Dmitry Torokhov wrote:
> >>On Sun, Apr 04, 2010 at 12:33:28AM +0200, Dominik Brodowski wrote:
> >>>4) SynPS/2 touchpad:
> >>>Why does moving the touchpad lead to sooo many IRQs? I can't look as fast
> >>>as the mouse pointer seems to get new data:
> >>> 62,5% (473,1)<interrupt> : PS/2 keyboard/mouse/touchpad
> >>80 pps @ 6 bytes/packet = 480 interrupts/sec.
> >>You can try using psmouse.rate=40 to limit it to 40 pps which should
> >>bring it to the rate of standard PS/2 mouse at the expense of
> >as a sidenote: if we know -- like here -- that the next IRQ will be issued
> >soon, in approximately 1.75 ms (well, at least on my system), might it make
> >sense to make tick_nohz_get_sleep_length() smarter to know about this?
> yes and no.
> if you are very sure (95%+ or so) then absolutely it needs to know about this
> so that the C state selection code can make a better decision.
> Right now it tries to look at history to guess this delay.
> Unfortunately we do not currently have such a concept in the code to make this
> work... but it'd be really nice to have.
Dmitry, are we "very sure" in this touchpad case?
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/