Re: IO scheduler based IO controller V10

From: Mike Galbraith
Date: Fri Oct 02 2009 - 10:46:03 EST


On Fri, 2009-10-02 at 07:24 -0700, Linus Torvalds wrote:
>
> On Fri, 2 Oct 2009, Jens Axboe wrote:
> >
> > It's really not that simple, if we go and do easy latency bits, then
> > throughput drops 30% or more.
>
> Well, if we're talking 500-950% improvement vs 30% deprovement, I think
> it's pretty clear, though. Even the server people do care about latencies.
>
> Often they care quite a bit, in fact.
>
> And Mike's patch didn't look big or complicated.

But it is a hack. (thought about and measured, but hack nonetheless)

I haven't tested it on much other than reader vs streaming writer. It
may well destroy the rest of the IO universe. I don't have the hw to
even test any hairy chested IO.

-Mike

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