CPU utilization on a dual-core

[mike ledoux]

On Fri, Nov 02, 2007 at 03:16:35PM -0500, Paul Lussier wrote:
> Does anyone know how to determine per-CPU utilization on a
> multi-cpu/core system.  It's a 2.4 kernel, and top doesn't break
> things down per-cpu.  Unless I'm running an ancient version of top...

Even ancient versions of top can do this, IME.  On modern versions,
use '1' to toggle displaying separate CPU states, and 'I' to toggle
between Irix and Solaris style SMP display (Irix displays process
%CPU as % of 1 CPU, Solaris displays as % of all CPUs).

> Also, how can you tell (without opening the box) if a system is
> multi-cpu vs. multi-core?

/proc/cpuinfo on the system I'm looking at now (two dual-core Xeons)
shows info like:

  physical id     : 0
  siblings        : 2
  core id         : 0
  cpu cores       : 2

for each processor.  From that I can make out that in this case
processors 0 and 2 are cores 0 and 1 on CPU 0, and processors 1 and
3 are cores 6 and 7 on CPU 3.  No idea why it isn't cores 0 and 1 on
CPU 1, but that's Intel for you.

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