Re: [PATCH] Re: Bad network performance over 2Gbps

On Mon, 21 Apr 2008, Rick Jones wrote:
Bodo Eggert wrote:
Kok, Auke <auke-jan.h.kok@xxxxxxxxx> wrote:

[X86] IRQBALANCE: Mark as BROKEN and disable by default

The IRQBALANCE option causes interrupts to bounce all around on SMP
systems
quickly burying the CPU in migration cost and cache misses. Mainly
affected
are network interrupts and this results in one CPU pegged in softirqd
completely.


If this is the problem, maybe it would help to only balance the IRQs each
e.g. ten seconds? Unfortunately I have no SMP system to try it out.

Be it kernel or user space, for consistent benchmark results it needs to be
able to be turned-off without turning the code. That leaves me in agreement
with Stephen that if it must exist, the user space one would be preferable.
It can be easily terminated with extreme prejudice.

I agree that having a full-featured userspace balancer daemon with lots of
intelligence will be theoretically better, but if you can have a simple
daemon doing OK on many machines for less than the userspace daemon's
kernel stack, why not?
--
Funny quotes:
31. Why do "overlook" and "oversee" mean opposite things?
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