Re: [patch] voluntary-preempt-2.6.9-rc1-bk4-Q5

Ingo Molnar
2004-08-31T19:32:22Z

* Thomas Charbonnel <thomas@undata.org> wrote:

> As you can see ~1ms was probably an accident, and the latency does not
> always come from do_timer. The constant is do_IRQ interrupting the
> idle thread.

(do you have any sort of powersaving mode (ACPI/APM) enabled? If yes,
could you try to tune it down as much as possible - disable any
powersaving option in the BIOS and in the .config - kill apmd, etc.)

but i dont think it's powersaving - why would such an overhead show up
in those functions. The only common thing seems to be that both
mark_offset_tsc() and mask_and_ack_8259A() does port IO, which is slow -
but still it shouldnt take ~0.5 msecs!

Ingo