Re: [PATCH] deadline io scheduler

[Jens Axboe <axboe@suse.de>]

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