Re: [resent PATCH] Re: very slow parallel read performance

Daniel Phillips
2001-08-26T21:13:57Z

On August 26, 2001 10:26 pm, Gérard Roudier wrote:
> On Sun, 26 Aug 2001, Daniel Phillips wrote:
>
> [...]
>
> > It should not be being ignored. This needs to be looked into. In any event,
> > the max-readahead proc setting is clearly good and needs to be in Linus's
> > tree, otherwise changing the default MAX_READAHEAD requires a recompile.
> > Worse, there is no way at all to specify the kernel's max-readahead for scsi
> > disks - regardless of the fact that scsi disks do their own readahead, the
> > kernel will do its own as well, with no way for the user to turn it off.
>
> For SCSI disks prefetch tuning you may look into the CACHING page.
>
> For example, you can tell the drive to stop prefetching as soon a command
> is ready by setting MINIMUM PRE-FETCH to zero.
>
> Unfortunately, not all SCSI disks allow to tune all the configuration
> parameters of the caching page.

In this case he's using ide.

--
Daniel