From: Paolo Ornati <ornati@lycos.it>
To: Ram Pai <linuxram@us.ibm.com>
Subject: Re: Strange IDE performance change in 2.6.1-rc1 (again)
Date: Wed, 7 Jan 2004 21:12:35 +0100
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On Wednesday 07 January 2004 20:23, Ram Pai wrote:
>
> I tried on my lab machine with scsi disks. (I dont have access currently
> to a spare machine with ide disks.)
>
> I find that reverting the changes in mm/filemap.c and then reverting the
> lazy-read optimization gives much better sequential read performance on
> blockdevices.  Is this your observation on IDE disks too?

Yes and No.
I have only tried to revert lazy-read optimization (without any visible 
change) so I have reapplied it AND THAN I have reverted changes in 
mm/filemap.c... and performance has gone back.

>
> > I don't know why... but it does.
>
> Lets see. I think my theory is partly the reason. But the changes in
> filemap.c seems to be influencing more.

YES, I agree.
I haven't done a lot of tests but it seems to me that the changes in 
mm/filemap.c are the only things that influence the sequential read 
performance on my disk.

-- 
	Paolo Ornati
	Linux v2.4.23

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