On Wed, Oct 12, 2005 at 03:11:14PM -0400, Woods, Jeff wrote:
> Is it possible to explicitly specify a value for the static metrics such
> as cpu_num?
>
> We have a number of nodes in our cluster which have hyperthreading
> enabled, where each physical CPU appears as two CPUs to the OS. Our
> applications are not threaded, so we get little or no benefit from
> having the hyperthreading enabled (yes, we could disable it in the BIOS,
> but I would like to leave it enabled "just in case"). Further, we have
> CPUs (in our head or I/O nodes, for instance) which will never be used
> for computation, but we would like to continue monitoring the nodes for
> network, load average, etc.
>
> Regardless, our cluster utilization shows 50%, even when actual cluster
> performance peaks near 100%. Our management finds this confusing, and
> I've had to explain it on a number of occasions. I would like to be
> able to adjust the number of CPUs reported per node to a more reasonable
> value -- the actual number of processors installed in each node which is
> used for computation.
>
> In my configuration file, I currently have:
>
> collection_group {
> collect_once = yes
> time_threshold = 1200
> metric {
> name = "cpu_num"
> }
> }
>
>
> Because there are two physical processors with hyperthreading, it shows
> as 4 CPUs. I would like to do something like this:
>
> collection_group {
> collect_once = yes
> time_threshold = 1200
> metric {
> name = "cpu_num"
> value = 2
> }
> }
>
> Is this possible?I think we should do this, but someone needs to step up and add the code. It's the only way to resolve this conflict in reporting a "correct" value for CPUs since the value of correct is site dependent. One note, for FPU intensive applications, you may actually see signficant throughput improvements if you run four instances on these machines. IIRC I saw roughtly 60% better throughput on [EMAIL PROTECTED] on early HTT CPUs. -- Brooks -- Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4
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