Re: [RFC 3/4] Disable scheduler tick when we are runningSCHED_FIFO tasks

[Jan Blunck]

On Wed, Sep 08, Peter Zijlstra wrote:

> On Wed, 2010-09-08 at 14:29 +0200, Jan Blunck wrote:
> > This patch is disabling the scheduler tick to go off when there is a task
> > with SCHED_FIFO policy running. Since these tasks are not timesliced anyway
> > we only care about timers, softirqs and such stuff just like when we disable
> > the tick during idle periods.
> > 
> 
> Also, doesn't this break any and all jiffies users?
> 

Sure. It was enough to make FTQ run.

> And you need to restart the tick on call_rcu() and everything else that
> requires the tick for processing.
> 

I realized that before as well but somehow forgot about it. Checking for a
disabled timer tick on syscall entry would help. Like we do on irq entry as
well.

Jan
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