Re: [PATCH] O17int

Mike Galbraith
2003-08-22T05:08:56Z

At 09:59 AM 8/22/2003 +1000, Con Kolivas wrote:
>Quoting Mike Galbraith <efault@gmx.de>:
>
> > > > 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