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Subject: Re: [OMPI devel] 0.9.1rc2 is available
From: Ashley Pittman (ashley_at_[hidden])
Date: 2009-10-22 05:54:14

On Thu, 2009-10-22 at 11:05 +0200, Brice Goglin wrote:
> Ashley Pittman wrote:

> > Does this imply the default is to report on processes in the current
> > cpuset rather than the entire system? Does anyone else feel that
> > violates the principal of least surprise?

> Yes, by default, it's the current cpuset. Maybe lstopo should report the
> whole system (it does if you pass --whole-system), or display a clear
> message saying that's it's only showing the current cpuset. Apart from
> lstopo, for real applications, I feel like using the current cpuset only
> is better.

I guess 95% of the time you run it by hand you won't have a cpuset so
it'll be the same anyway and when you do have a cpuset then it's
probably what you are interested in.

Could I add a feature request that you can query the topology for other
arbitrary processes in the system? I've taken a look at the source and
it appears I could add this for Linux easily enough (I assume I could
just change /proc/self/ in src/topology-linux.c:1005?) but doing the
same for other operating systems isn't something I could do.

It would be a two minute job to add this to padb which would allow you
to see the topology of all processes within a parallel job at run-time
without needing to interrupt the job.


Ashley Pittman, Bath, UK.
Padb - A parallel job inspection tool for cluster computing