Re: Horrendous Audio Stutter - current git

From: Frans Pop
Date: Fri May 02 2008 - 14:53:39 EST


On Friday 02 May 2008, Frans Pop wrote:
> As I had group scheduling disabled, I only saw the first one. But my
> audio skips were a lot less severe than Parag described. And disabling
> group scheduling helped solve the problem for him.
>
> So it may well still be worth following up on this.

I have just tested a kernel with GROUP_SCHED enabled (with Peter's patch
still included) and can confirm that enabling group scheduling causes
serious latencies.
Skips are much more frequent than with the issue that was just solved.

latencytop shows (different samples)
Scheduler: waiting for cpu 537.7 msec
Scheduler: waiting for cpu 172.0 msec
Scheduler: waiting for cpu 414.6 msec
Scheduler: waiting for cpu 455.7 msec
Scheduler: waiting for cpu 446.5 msec

I think I also see why....

# grep bonus_max `grep -l amarokapp /proc/*/task/*/sched`
/proc/4725/task/20645/sched:se.bonus_max : 122640.203776
/proc/4725/task/4725/sched:se.bonus_max : 122640.203776
/proc/4725/task/4793/sched:se.bonus_max : 41902109.884416
/proc/4725/task/4797/sched:se.bonus_max : 41902109.884416
/proc/4725/task/4798/sched:se.bonus_max : 41902109.884416
/proc/4725/task/4799/sched:se.bonus_max : 40880.046080
/proc/4725/task/4800/sched:se.bonus_max : 19.970683
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