Re: [RFC][PATCH] sched: SCHED_FIFO watchdog timer

[Lennart Poettering <mzxreary@0pointer.de>]

On Sun, 14.10.07 00:51, Peter Zijlstra (a.p.zijlstra@chello.nl) wrote:

> The below patch is an idea proposed by tglx and depends on sched-devel +
> the hrtick patch previously posted.
> 
> The current watchdog action is to demote the task to SCHED_NORMAL,
> however it might be wanted to deliver a signal instead (or have more per
> task configuration state). Which is why I added Lennart to the CC list
> as I gathered he would like something like this for PulseAudio.

Indeed! Having this in the kernel would allow us to enable RT
scheduling for PulseAudio by default without bad effects. I was thinking about
adding some kind of babysitting process to userspace -- but doing this as
an RLIMIT in the kernel strikes me a much better idea!

I think it would make a lot of sense to make the API very similar to
RLIMIT_CPU, i.e. also send out SIGXCPU and SIGKILL, with the single
difference that RLIMIT_CPU sends out a signal depending on the total
CPU time used for the process and the new RLIMIT based on the time the
process spent without sleeping. That would be a very reasonable
extension to the current RLIMIT_CPU model.

Thank you very much for doing this patch!

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
http://0pointer.net/lennart/           GnuPG 0x1A015CC4
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