Re: Time sliced CFQ io scheduler

Jens Axboe
2004-12-08T09:37:09Z

On Wed, Dec 08 2004, Jens Axboe wrote:
> > Hmm, damn. Lots of stuff. I guess some of the notable ones that I've
> > had trouble with are OraSim (Oracle might give you a copy), Andrew's
> > patch scripts when applying a stack of patches, pgbench... can't
> > really remember any others off the top of my head.
>
> The patch scripts case is interesting, last night (when committing other
> patches) I was thinking I should try and bench that today. It has a good
> mix of reads and writes.

AS is currently 10 seconds faster for that workload (untar of a kernel
and then applying 2237 patches). AS completes it in 155 seconds, CFQ
takes 164 seconds.

I still need to fix the streamed write perfomance regression, then I'll
see how the above compares again. CFQ doesn't do very well in eg
tiobench streamed write case (it's about 30% slower than AS).

(btw, any mention of CFQ in this thread refers to time sliced cfq).

--
Jens Axboe