Re: bad networking related lag in v2.6.22-rc2

From: Ingo Molnar
Date: Mon May 21 2007 - 04:12:52 EST



* Ingo Molnar <mingo@xxxxxxx> wrote:

> > ouch! a nearly 1 second delay got observed by the scheduler - something
> > is really killing your system!
>
> ah, you got the latency tracer from Thomas, as part of the -hrt patchset
> - that makes it quite a bit easier to debug. [...]

and ... you already did a trace for Thomas, for the softirq problem:

http://cybertek.info/taitai/trace.txt.bz2

this trace shows really bad networking related kernel activities!

gkrellm-5977 does this at timestamp 0:

gkrellm-5977 0..s. 0us : cond_resched_softirq (established_get_next)

2 milliseconds later it's still in established_get_next() (!):

gkrellm-5977 0..s. 2001us : cond_resched_softirq (established_get_next)

and the whole thing takes ... 455 msecs:

gkrellm-5977 0..s. 455443us+: cond_resched_softirq (established_get_next)

i think this suggests that you have tons of open sockets. What does
"netstat -ts" say on your box?

Ingo
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