Re: SATA Harddisk speed drop of 100 MB/s

[Arjan van de Ven]

On Wed, 2007-06-20 at 19:06 -0400, Jeff Garzik wrote:
> Carlo Wood wrote:
> > hdparm -tT gives over 160 MB/s for my tripple 10k rpm Raptor RAID5
> > on 2.6.18, as expected.
> > 
> > In 2.6.22-rc5 this dropped to only 60 MB/s !
> > 
> > Is this a known issue?
> > 
> > I also measured it with bonnie; I get 108 MB/s reading speed on
> > 2.6.18 and only 68 MB/s on 2.6.22-rc5.
> 
> More info needed...  kernel config, before-and-after dmesg output, lspci 
> output.




also do a 

echo 60 > /proc/sys/vm/dirty_ratio

first to see if that helps

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