Re: [patch] CFS scheduler, -v19

Markus
2007-07-16T17:59:42Z

> > [...] The mouse is smooth, just when one app is being quit (dont
> > know why...) the mouse will be jerking for a few seconds...
> is the mouse jerky on any app quitting?
No.

> Or is your observation the following: _sometimes_ apps quit
> unexpectedly (their window just vanishes?), and _at the same time_,
> the mouse becomes jerky as well, for a few seconds?
Exactly.

> the mouse typically only becomes jerky when there's some really high
> load on the system - anything else would be a kernel bug. A jerky
> mouse on an unloaded system is definitely a sign of some sort of
> kernel bug (in or outside of the scheduler). An app vanishing
> unexpectedly might mean an OOM-kill - but that would should up in the
> syslog as well.
> Pretty weird.
Well, the system uses about 30% of the cpu (cool'n'quite put it on the
lowest frequency).

I made a plain 2.6.22.1 and could use it for about 2 hours without
any problem. Then I applied the cfs-v19 for that kernel, rebuild from
mrproper with the saved config and booted. After a few minutes the
first app vanished... some more followed by time (I just surfed around
a bit...)

The dmesg output is not differing in any interesting point (just some
numbers, like raid-benchmark, some irqs or usb-numbers...)

So its obviously something within cfs... unfortunately...

> Can you make this regression trigger arbitrarily, so that we could
> debug it better? Apps exiting unexpectedly can be debugged via:
>
http://kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.22-rc6/2.6.22-rc6-mm1/broken-out/vdso-print-fatal-signals.patch
>
> you can turn it on via the print-fatal-signals=1 boot option or via:
>
> echo 1 > /proc/sys/kernel/print-fatal-signals
>
> this feature will produce a small dump to the syslog about every app
> that exits unexpectedly. Note that this might not cover all types of
> "window suddenly vanishes" regressions.
Nothing is printed for a disapeared app for me.

Is there anything more I can try?

Markus