[torquedev] Feedback on per vnode cpusets

Chris Samuel csamuel at vpac.org
Sat May 24 04:11:04 MDT 2008

Hi all,

I'm currently looking at the cpuset code in trunk and
wondering what to do about the per-vnode cpusets.

It's a trivial change to pbs_mom put the tm_spawn children
into the job cpuset, so the question is rather how to
handle the differences.

In either of the cases where the per-vnode cpusets remain
I would strongly suggest that they default to off (so as
not to surprise unsuspecting sites).

So, the options I can see are:

1) per-vnode cpusets are a compile time option

Requires some autoconf tweaks and a #ifdef and if
a site changes their mind its a recompile, reinstall
and restart pbs_mom cycle.

2) per-vnode cpusets are a pbs_mom.conf option

Plagiarise, er, be inspired by the enablemomrestart
code and create a new global variable.  If a site changes
its mind it changes the config file and reloads/restarts

3) per-vnode cpusets go altogether

Easiest to do, but removes the ability for sites using
MPICH-1 based MPI's like MPICH-GM, MVAPICH1, etc, from
being able to lock individual tasks to cores.

Thoughts ?

Christopher Samuel - (03) 9925 4751 - Systems Manager
 The Victorian Partnership for Advanced Computing
 P.O. Box 201, Carlton South, VIC 3053, Australia
VPAC is a not-for-profit Registered Research Agency

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