What's the status of parallel netisr?

Kevin Oberman oberman at es.net
Tue Sep 16 18:46:39 UTC 2008


> Date: Tue, 16 Sep 2008 22:43:25 +0800
> From: "Jian Qiu" <swordqiu at gmail.com>
> Sender: owner-freebsd-net at freebsd.org
> 
> Interesting.
> 
> I did a test on local UDP throughput.
> 
> I was surprised to find out the performance with a SMP kernel was
> worse than UP. (~74MB/s v.s. 96 MB/s).

Look at CPU affinity. I have seen significant jumps in performance when
things switch between CPUs. It's best to lock the UDP cannon to a
single CPU and that the CPU not be CPU0. (This applies to both BSD and
Linux systems that I have worked with.)
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751
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