svn commit: r265792 - head/sys/kern
slw at zxy.spb.ru
Sun May 11 08:31:18 UTC 2014
On Sat, May 10, 2014 at 12:53:37AM +0000, Adrian Chadd wrote:
> Author: adrian
> Date: Sat May 10 00:53:36 2014
> New Revision: 265792
> URL: http://svnweb.freebsd.org/changeset/base/265792
> Add in support to optionally pin the swi threads.
> Under enough load, the swi's can actually be preempted and migrated
> to other currently free cores. When doing RSS experiments, this lead
> to the per-CPU TCP timers not lining up any more with the RX CPU said
> flows were ending up on, leading to increased lock contention.
> Since there was a little pushback on flipping them on by default,
> I've left the default at "don't pin."
> The other less obvious problem here is that the default swi
> is also the same as the destination swi for CPU #0. So if one
> pins the swi on CPU #0, there's no default floating swi.
> A nice future project would be to create a separate swi for
> the "default" floating swi, as well as per-CPU swis that are
> (optionally) pinned.
I have 10.0 box with aprox. 16Gbit TCP at peak.
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