Re: Odd IDE performance drop 2.4 vs 2.6?

[Nick Piggin]

Alan Cox wrote:

> On Llu, 2005-06-13 at 15:06, Nick Piggin wrote:
>
> > > Make sure you have pre-empt disabled and the antcipatory I/O scheduler
> > > disabled. 
> > I don't think that those could explain it.
>
> Try it and see. The anticipatory I/O scheduler does horrible things to
> my IDE streaming performance numbers and to swap performance. It tries
> to merge I/O by delaying it which is deeply ungood when it comes to IDE
> streaming even if its good for general I/O.
Sure it has regression cases here and there, as you would expect.
But I'm fairly sure this won't be one of them. If there is just a
single process submitting the IO the anticipatory scheduler should
completely turn of any delays, and degenerate basically to the
deadline scheduler.


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