Messages in this thread | | | Date | Wed, 26 Sep 2007 11:34:45 +0200 | From | Ingo Molnar <> | Subject | Re: Network slowdown due to CFS |
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* Martin Michlmayr <tbm@cyrius.com> 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://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-devel.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?
as a starter, could you boot the sched-devel.git kernel, with CONFIG_SCHED_DEBUG=y and CONFIG_SCHEDSTATS=y enabled and could you run this script while the iperf test is in the middle of its testrun:
http://people.redhat.com/mingo/cfs-scheduler/tools/cfs-debug-info.sh
this will gather a good deal of info about the workload in question. Please send me the resulting debug file.
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