Re: Performance regression in IO scheduler still there

Jeff Moyer
2009-10-26T17:27:39Z

Jan Kara <jack@suse.cz> writes:

> Hi,
>
> I took time and remeasured tiobench results on recent kernel. A short
> conclusion is that there is still a performance regression which I reported
> few months ago. The machine is Intel 2 CPU with 2 GB RAM and plain SATA
> drive. tiobench sequential write performance numbers with 16 threads:
> 2.6.29: AVG STDERR
> 37.80 38.54 39.48 -> 38.606667 0.687475
>
> 2.6.32-rc5:
> 37.36 36.41 36.61 -> 36.793333 0.408928
>
> So about 5% regression. The regression happened sometime between 2.6.29 and
> 2.6.30 and stays the same since then... With deadline scheduler, there's
> no regression. Shouldn't we do something about it?

Background:
http://lkml.org/lkml/2009/5/28/415

Thanks for bringing this up again. I'll try to make some time to look
into it if others don't beat me to it.

Cheers,
Jeff