On Mon, 01 Jan 2007 23:46:58 +0100 Rene Herman <[EMAIL PROTECTED]> wrote:
> > Everything seems fine in the dmesg. Performance degradation is > > probably some other issue in -rc kernel. I'm suspecting recently > > fixed block layer bug. If it's still the same in the next -rc, > > please report. > > In fact, it's CFQ. The PATA thing was a red herring. 2.6.20-rc2 and 3 > give me ~ 24 MB/s from "hdparm t /dev/hda" while 2.6.20-rc1 and below > give me ~ 50 MB/s. > > Jens: this is due to "[PATCH] cfq-iosched: tighten allow merge > criteria", 719d34027e1a186e46a3952e8a24bf91ecc33837: > > http://www2.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=719d34027e1a186e46a3952e8a24bf91ecc33837 > > If I revert that one, I have my 50 M/s back. config and dmesg attached > in case they're useful. The patch would appear to need this fix: --- a/block/cfq-iosched.c~a +++ a/block/cfq-iosched.c @@ -592,7 +592,7 @@ static int cfq_allow_merge(request_queue if (cfqq == RQ_CFQQ(rq)) return 1; - return 1; + return 0; } static inline void _ But that might not fix things... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/