Re: preempt-timing-2.6.8-rc1

Lenar Lõhmus
2004-07-13T15:32:17Z

William Lee Irwin III wrote:

>Wild guess is that you took an IRQ in dec_preempt_count() and that threw
>your results off. Let me know if the patch below helps at all. My guess
>is it'll cause more apparent problems than it solves.
>
Machine in question is XP2500+@1.84GHz (it was overlocked@2.25GHz during
last test, now running at
official speed). Is this really slow for 1ms?

Applied your patch. Booted.

With preempt_thresh=1 I still got tons of those violations at schedule().

With preempt_thresh=2 I do not get those anymore. Apart from sys_ioctl()
violation, getting now these:

16ms non-preemptible critical section violated 2 ms preempt threshold
starting at exit_notify+0x1d/0x7b0 and ending at schedule+0x291/0x480
7ms non-preemptible critical section violated 2 ms preempt threshold
starting at kmap_atomic+0x13/0x70 and ending at kunmap_atomic+0x5/0x20
6ms non-preemptible critical section violated 2 ms preempt threshold
starting at fget+0x28/0x70 and ending at fget+0x41/0x70

No apparent side-effects noticed.

As before, when running mplayer I'm getting many sys_ioctl() things
coupled with messages:
rtc: lost some interrupts at 1024Hz.
It happens when madly seeking around in video.

Lenar