Re: miserable performance of 2.6.21 under network load

[Andi Kleen]

Aaron Porter <atporter@xxxxxxxxxxx> writes:

> 	I'm in the process up upgrading a pool of apache servers from
> 2.6.17.8 to 2.6.21.5, and we're seeing a pretty major change in behavior.
> Under identical network load, 2.6.21 has a load average more than 3 times
> higher, cpu 0 spends well over 90% of its time in interrupts (vs ~30%
> under 2.6.17). When we hit 3k apache sessions, ksoftirqd eats 100% of cpu0
> and our network traffic drops off rapidly. The end result is that 2.6.17
> performs twice as well under this load.

Can you oprofile it?

-Andi
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