linux-kernel - Re: CPU numbering & hyperthreading

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Date:	Tue, 18 Jul 2006 16:46:51 -0400
From:	Chuck Ebbert <76306.1226@...puserve.com>
To:	Andrew Athan <aathan_linux_kernel_1542@...akmail.com>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: CPU numbering & hyperthreading

In-Reply-To: <44BC4200.90308@...akmail.com>

On Mon, 17 Jul 2006 22:05:52 -0400, Andrew Athan wrote:
>
> I have two highly CPU/memory/network intensive processes with 3-5 
> threads each.  I am using sched_setaffinity calls to make sure these two 
> processes never compete for the same physical CPU.  Am I right to assume 
> that CPU #0 and #1 vs CPU #2 and #3 are separate physical CPUs on a 
> 2-CPU w/ hyperthreading box?
> 
> I've spent some time looking, but I did not find documentation on 
> exactly how CPUs are numbered in a hyperthreaded box.

There's no fixed numbering.

If you want to know the die/core/thread layout, check out
Documentation/cputopology.txt.

-- 
Chuck
And did we tell you the name of the game, boy, we call it Riding the Gravy Train.
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