[linux-audio-dev] SCHED_FIFO watchdog util (was: 2.4.20 + lowlat +preempt + alsa + jack = dead computer)

Josh Green jgreen at users.sourceforge.net
Tue Jan 7 22:11:01 UTC 2003


On Tue, 2003-01-07 at 18:07, Fernando Pablo Lopez-Lezcano wrote:
> 
> One more (small) datapoint. Roger Larsson sent me off the list a couple
> of small utilities (VERY nice tools!) that monitors the cpu usage of
> SCHED_FIFO processes and after a timeout actually downgrades the
> persistent hogs to SCHED_OTHER. 
> 
> So I run that in a terminal and after playing around with a bunch of
> jack apps got the machine to lockup... and then, after a little bit,
> suddenly, it came back to life! (you could see that the monitor had
> changed the priority of the hogs to SCHED_OTHER). 
> 

Wow, I must have that as well. I have been wondering about the existence
of such utilities. It seems kind of sad to trade off low latency for
instability. A few times I was driving FluidSynth (was called iiwusynth)
running SCHED_FIFO with a sequencer and got the tempo going too fast.
Hack.. cough.. reboot..

Seems like something like that should actually be part of the kernel (a
configurable option of course, for those die hard SCHED_FIFO folks). It
would not be good for the community at large to think of Linux and audio
as being unstable just because some badly behaving processes wont give
the machine back to their mouse and keyboard :) Cheers.
	Josh Green

P.S. Where can I find the mentioned utility?

> 
> -- Fernando
> 





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