On Mon, Mar 21, 2005 at 08:27:26PM -0500, Dan Maas wrote:
> Is there a canonical way for user-space software to determine how many
> real CPUs are present in a system (as opposed to HyperThreaded or
> otherwise virtual CPUs)?
>
> We have an application that for performance reasons wants to run one
> process per CPU. However, on a HyperThreaded system /proc/cpuinfo
> lists two CPUs, and running two processes in this case is the wrong
> thing to do. (Hyperthreading ends up degrading our performance,
> perhaps due to cache or bus contention).
Compare the 'physical id' fields of /proc/cpuinfo, and count
how many unique values you get.
Ie, on my dual+ht, I see..
physical id : 0
physical id : 0
physical id : 3
physical id : 3
Which indicates 2 real CPUs split in two.
Dave
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
