Re: [openib-general] Re: [PATCH 07/16] ehca: interrupt handling routines

From: Roland Dreier
Date: Tue May 09 2006 - 14:36:11 EST


Shirley> I have done some patch like that on top of splitting
Shirley> CQ. The problem I found that hardware interrupt favors
Shirley> one CPU. Most of the time these two threads are running
Shirley> on the same cpu according to my debug output. You can
Shirley> easily find out by cat /proc/interrupts and
Shirley> /proc/irq/XXX/smp_affinity. ehca has distributed
Shirley> interrupts evenly on SMP, so it gets the benefits of two
Shirley> threads, and gains much better throughputs.

Yes, an interrupt will likely be delivered to one CPU.

But there's no reason why the two threads can't be pinned to different
CPUs or given exclusive CPU masks, exactly the same way that ehca
implements it.

- R.
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