Recommended SMP Config

John Baldwin jhb at
Fri Mar 17 16:40:11 UTC 2006

On Friday 17 March 2006 09:04, Tom Daly wrote:
> Hi,
> I'm running FreeBSD 6.0 Release (amd64) on Dell Poweredge 2850s. So far, 
> so good. I'm doing a pretty vanilla install of things, enabling SMP in the 
> kernel, and that's pretty much it. This server has 2 EM64T CPUs in it.
> When looking at top, CPU 1 rarely shows up with processes on it. systat 
> does show it idle most of the time. Why is this? Why do processes land on 
> CPU 0, 2, and 3 in most cases.
> Also, by setting machdep.hyperthreading_allowed=1, CPU 1 starts taking 
> process onto it.

Because CPU 1 is a hyperthread.  So is CPU 3 for that matter.

John Baldwin <jhb at>  <><
"Power Users Use the Power to Serve"  =

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