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DateMon, 29 Dec 2003 21:09:34 -0800
FromWilliam Lee Irwin III <>
SubjectRe: 2.6.0 performance problems
On Tue, 2003-12-30 at 00:58, Thomas Molina wrote:
>> It certainly looks like DMA is enabled.  Under 2.4 I get:
>> [root@lap root]# hdparm /dev/hda
[...]
>>  readahead    =  8 (on)
[...]
>> Under 2.6  I get:
>> [root@lap root]# hdparm /dev/hda
[...]
>>  readahead    = 256 (on)

On Tue, Dec 30, 2003 at 01:14:45AM +0200, Martin Schlemmer wrote:
> Increase your readahead:
>  # hdparm -a 8192 /dev/hda
> BTW:  As we really do get this question a _lot_ of times, why
>       don't the ide layer automatically set a higher readahead
>       if there is enough cache on the drive or something?

Could you try lowering 2.6's readahead to 2.4's levels in order to rule
out readahead-induced thrashing?


-- wli
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