Messages in this thread | | | Date | Wed, 15 Jun 2005 21:15:41 +0200 | From | Ondrej Zary <> | Subject | Re: Odd IDE performance drop 2.4 vs 2.6? |
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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.
Now I've tested it with preempt disabled and nothing has changed. When fiddling around with hdparm, I got about 16MB/s max. with 2.6.12-rc5. With 2.4.31, I got about 21MB/s when just the DMA was enabled (read-ahead and multcount set to 0 - changing them does not make almost any difference).
-- Ondrej Zary - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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