Re: [REPORT] cfs-v4 vs sd-0.44

Ingo Molnar
2007-04-22T13:28:42Z

* Mark Lord <lkml@rtr.ca> wrote:

> > i've not experienced a 'runaway X' personally, at most it would
> > crash or lock up ;) The value is boot-time and sysctl configurable
> > as well back to 0.
>
> Mmmm.. I've had to kill off the odd X that was locking in 100% CPU
> usage. In the past, this has happened maybe 1-3 times a year or so on
> my notebook.
>
> Now mind you, that usage could have been due to some client process,
> but X is where the 100% showed up, so X is what I nuked.

well, i just simulated a runaway X at nice -19 on CFS (on a UP box), and
while the box was a tad laggy, i was able to killall it without
problems, within 2 seconds that also included a 'su'. So it's not an
issue in CFS, it can be turned off, and because every distro has another
way to renice Xorg, this is a convenience hack until Xorg standardizes
it into some xorg.conf field. (It also makes sure that X isnt preempted
by other userspace stuff while it does timing-sensitive operations like
setting the video modes up or switching video modes, etc.)

Ingo