Re: [PATCH] deadline io scheduler

Jens Axboe
2002-09-26T06:54:45Z

On Thu, Sep 26 2002, Jens Axboe wrote:
> > Now alter fifo_batch, everything else default:
> >
> > fifo_batch (units) time cat kernel/*.c (secs)
> > 64 5.0
> > 32 2.0
> > 16 0.2
> > 8 0.17
> >
> > OK, that's a winner.
>
> Cool, I'm resting benchmarks with 16 as the default now. I fear this
> might be too agressive, and that 32 will be a decent value.

fifo_batch=16 drops throughput slightly on tiobench, however it also
gives really really good interactive behaviour here. Using 32 doesn't
change that a whole lot, the throughput that is. This might just be
normal deviation between runs, more are needed to be sure. Note that
I'm testing with the last_sec patch I posted, you should too.

BTW, for SCSI, it would be nice to first convert more drivers to use the
block level queued tagging. That would provide us with a much better
means to control starvation properly on SCSI as well.

--
Jens Axboe