lkml.org 
[lkml]   [2005]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [patch, 2.6.11-rc2] sched: RLIMIT_RT_CPU_RATIO feature
From
Date
On Wed, 2005-01-26 at 23:15 -0600, Jack O'Quin wrote:
> >> > And finally, with rlimit support, is there any reason why lockup
> >> > detection and correction can't go into userspace? Even RT
> >> > throttling could probably be done in a userspace daemon.
> >>
> >> It can. But, doing it in the kernel is more efficient, and probably
> >> more reliable.
> >
> > Possibly. But the people who want a solution seem to be in a very
> > small minority, and I'm not sure how much you care about efficiency.
>
> I do care. The average overhead of running a watchdog daemon at max
> priority is tiny. But, its impact on worst-case trigger latencies is
> non-trivial and must be added to everything else in the RT subsystem.

Keep in mind that with the max RT prio rlimit solution audio systems
using JACK would not even need the external watchdog thread, because
JACK already has its own watchdog thread. I also like the max RT prio
rlimit approach with (optional) watchdog thread running as root because
it really seems to be the least intrusive out of several good solutions
to the problem and puts policy details (when to throttle an RT thread)
in userspace.

Lee

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:09    [W:0.122 / U:4.144 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site