Re: [PATCH 0/8][RFC] IO latency/throughput fixes

From: Linus Torvalds
Date: Mon Apr 06 2009 - 11:47:51 EST




On Mon, 6 Apr 2009, Jens Axboe wrote:
>
> > Jens - I can just apply this queue (I want to test it out anyway), or if
> > you prefer I can pull from you. Just tell me.
>
> Whatever you want, if you want to pull instead of manually applying,
> it's:
>
> git://git.kernel.dk/linux-2.6-block.git blk-latency

Ok, I applied them for testing anyway, so I think I'll just keep the
series I have in my tree. I'm keeping my nasty "dd+sync" going in the
background, just to verify that things really feel better, but I'm already
convinced this is a winner. Especially with the request size limiter, I
can really read email _almost_ as if nothing else was going on on the
machine.

With that request size limiting, my fsync pauses tend to be in the 250ms
range, with a one 0.75s outlier in the last few minutes. I can definitely
feel that quarter-second thing, and the .75s pause was a real stutter, but
boy what a difference. I don't get the uncontrollable urge to kill that
nasty background writer any more.

Linus
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