[PATCH] Re: linux readahead setting?

From: Roger Larsson (roger.larsson@skelleftea.mail.telia.com)
Date: Tue Nov 13 2001 - 19:37:05 EST

On Tuesday 13 November 2001 16:21, Roy Sigurd Karlsbakk wrote:
> Hi
>
> I heard linux does <= 32 page readahead from block devices
> (scsi/ide/que?). Is there a way to double this? I want to read 256kB
> chunks from the SCSI drives, as to get the best speed. These numbers are
> based on some testing and information I've got from Compaq's storage guys.
>
> roy

Note that the interface to /proc/ide/hdX/settings still is buggy...

i.e you should be able to do (in pages):
echo "file_readahead:64" > /proc/ide/hdX/settings
but the result will be a readahead of 128*1024 PAGES... and that
is too much... (even 1024 PAGES is too much)

(after patch, in kB)
echo "file_readahead:256" > /proc/ide/hdX/settings

It is likely that there are more settings in the ide subsystem that is
has this fault... (Andre, I keep repeating myself...)

/RogerL 

-- 
Roger Larsson
Skellefteċ
Sweden
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This archive was generated by hypermail 2b29 : Thu Nov 15 2001 - 21:00:37 EST