Re: Network slowdown due to CFS

From: Mike Galbraith
Date: Wed Sep 26 2007 - 06:23:41 EST

On Wed, 2007-09-26 at 10:52 +0200, Martin Michlmayr wrote:
> I noticed that my network performance has gone down from 2.6.22
> >from [ 3] 0.0-10.0 sec 113 MBytes 95.0 Mbits/sec
> to [ 3] 0.0-10.0 sec 75.7 MBytes 63.3 Mbits/sec
> with 2.6.23-rc1 (and 2.6.23-rc8), as measured with iperf.
> I did a git bisect today and tracked it back to the commit where CFS
> was enabled ("sched: cfs core code; apply the CFS core code",
> commit dd41f596cda0d7d6e4a8b139ffdfabcefdd46528). I also compiled a
> kernel from
> git://
> but things don't improve.
> This is on a Thecus N2100, an ARM (Intel IOP32x) based storage device
> with a r8169 card, SATA disks and 512 MB RAM. My config is attached.
> What kind of information can I supply so you can track this down?

I noticed on the iperf website a patch which contains sched_yield().

Do you have that patch applied by any chance? If so, it might be a
worth while to try it without it.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at