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Date: Fri, 11 Apr 2014 17:53:14 -0700
From: Peter Grehan <grehan@freebsd.org>
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To: Steve Wills <swills@FreeBSD.org>
Subject: Re: pinning CPUs in bhyve
References: <20140411194855.GA59594@mouf.net>
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Hi Steve,

> Can someone help me understand the cpu pinning feature in bhyve? I'm afraid the
> docs have confused me:
>
>   -p pinnedcpu
>    Force guest virtual CPUs to be pinned to host CPUs.  Virtual CPU n is pinned
>    to host CPU pinnedcpu+n.
>
> What would the arg looks like? Something like -p 0,1,2,3 ?

  No - currently the parameter can only select the starting host CPU 
e.g. "-p 3" for a quad vCPU guest will force the vCPU threads to be 
pinned to host CPUs 3,4,5 and 6.

> Also, is there like to be much or any benefit from it?

  Not really. It's for very specialized use cases, and could actually 
hurt performance. Not too different in that respect than cpuset with 
user processes.

later,

Peter.