Re: A few questions and issues with dynticks, NOHZ and powertop

From: Dominik Brodowski
Date: Sun Apr 04 2010 - 06:47:37 EST


Hey,

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
> sensitivity...

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?

Best,
Dominik
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