Avery Fay writes..
>I'm working with a dual xeon platform with 4 dual e1000 cards on different
>pci-x buses. I'm having trouble getting better performance with the second
>cpu enabled (ht disabled). With a UP kernel (redhat's 2.4.18), I can route
>about 2.9 gigabits/s at around 90% cpu utilization. With a SMP kernel
>(redhat's 2.4.18), I can route about 2.8 gigabits/s with both cpus at
>around 90% utilization. This suggests to me that the network code is
>serialized. I would expect one of two things from my understanding of the
>2.4.x networking improvements (softirqs allowing execution on more than
>one cpu):
>1.) with smp I would get ~2.9 gb/s but the combined cpu utilization would
>be that of one cpu at 90%.
>2.) or with smp I would get more than ~2.9 gb/s.
>Has anyone been able to utilize more than one cpu with pure forwarding?
I have not used pure forwarding, however I have seen network performance
improved using O(1) scheduler on SMP machines. Can you bind the process/irq
to cpu? That will give you a great boost in scalability/throughput.
Regards,
Mala
Mala Anand
IBM Linux Technology Center - Kernel Performance
E-mail:manand@us.ibm.com
http://www-124.ibm.com/developerworks/opensource/linuxperf
http://www-124.ibm.com/developerworks/projects/linuxperf
Phone:838-8088; Tie-line:678-8088
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