Re: iowait problems on 2.6, not on 2.4

[Andrew Morton]

Doug Ledford <dledford@xxxxxxxxxx> wrote:
>
> But, I could be wrong.  Give it a try and see what happens.  In the 2.4
>  kernels I would tell you to tweak /proc/sys/vm/{min,max}-readahead,
>  don't know if those two knobs still exist in 2.6 and if they have the
>  same effect.  Andrew?

blockdev --setra N /dev/sda 			(N is in 512 byte units)

echo N > /sys/block/sda/queue/read_ahead_kb	(N is in kilobytes)

Also there was breakage (recently fixed) in which /dev/sdaN's readahead
setting was being inherited from the blockdev on which /dev resides.  But
reading regular files is OK.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/