Re: Linux I/O performance in 2.3.99pre

From: Jens Axboe (
Date: Wed May 24 2000 - 10:12:19 EST

On Wed, May 24 2000, Paul Barton-Davis wrote:
> Now, *this* is interesting. I was getting 18MB/sec (IBM UltraStar 10K)
> under 2.3.51, and I can't get close to that under 2.3.99-anything.
> So: (1) where do I get elvtune ? (2) it sounds as if this should work
> without the classzone patch, meaning that the pre9-pre2+quintela fixes
> for VM plus elvtune might get me back to a reasonable level of
> performance. Andrea - any thoughts on this ?

1) I think newer util-linux include it, otherwise just look at the
ioctl and write a small 10 line c proggy to do it.

2) Try it.

> >While at it, could you explain what are write bomb logic and latency
> >numbers? What do they define?
> I'd love to know this as well.

The write bomb logic is meant prevent big writes from hurting
interactiveness and the latency numbers are used when sorting
a request into the list (to prevent starving some requests).

*  Jens Axboe <>
*  Linux CD/DVD-ROM, SuSE Labs

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