Re: [PATCH] O17int
From: Mike Galbraith
Date: Fri Aug 22 2003 - 00:14:05 EST
At 09:59 AM 8/22/2003 +1000, Con Kolivas wrote:
Quoting Mike Galbraith <efault@xxxxxx>:
> > > The most generally effective form of the "down-shift" anti-starvation
> > > tactic that I've tried, is to periodically check the head of all queues
> > > below current position (can do very quickly), and actively select the
> > > oldest task who hasn't run since some defined deadline. Queues are
> > > serviced based upon priority most of the time, and based upon age some
> of
> > > the time.
> >
> >Hmm also sounds fudgy.
>
> Yeah. I crossbred it with a ~deadline scheduler, and created a mutt.
But how did this mutt perform?
At the time, I was more concerned by the very long semaphore hold times I
was seeing than anything else. That it helped quite a lot. It didn't hurt
throughput in any way I could see, and it improved irman's latency
numbers. (process load was routinely hitting ~1.5 seconds max latency at
the time, that tree cut it to roughly 400-500ms iirc) Just like anything
else that increases fairness though, it hurt X feel somewhat in the
presence of load.
-Mike
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