Re: Odd IDE performance drop 2.4 vs 2.6?

From: Alan Cox
Date: Fri Jun 17 2005 - 07:44:10 EST

On Mer, 2005-06-15 at 20:15, Ondrej Zary wrote:
> 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).

multcount is only used for PIO so that would be expected. Similarly the
block readahead should matter but not anything drive level.

If you compare the hdparm data are both 2.4 and 2.6 selecting the same
IDE modes ?

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