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Subject: [OMPI users] Mixing Linux's CPU-shielding with mpirun's bind-to-core
From: Siddhartha Jana (siddharthajana24_at_[hidden])
Date: 2013-08-17 23:34:52


My requirement:
1. Avoid the OS from scheduling tasks on cores 0-7 allocated to my process.
2. Avoid rescheduling of processes to other cores.

My solution: I use Linux's CPU-shielding.
[ Man page:
I create a cpuset called "socket1" with cores 8-15 in the dev fs. I iterate
through all the tasks in /dev/cpuset/tasks and copy them to
I create a cpuset called "socket0" with cores 0-7 .
At the start of the application, (before MPI_Init()), I schedule my MPI
process on the cpuset as follows:
sprintf(str,"/bin/echo %d >> /dev/cpuset/socket0/tasks ",mypid);
In order to ensure that my processes remain bound to the cores, I am
passing the --bind-to-core option to mpirun. I do this, instead of using
sched_setaffinity from within the application. Is there a chance that
mpirun's "binding-to-core" will clash with the above ?

While this solution seems to work temporarily, I am not sure whether this
is good solution, given mpirun's own techniques of binding to cores,
scheduling processes by slot, et al.

Will mpirun's bind-by-slot technique guarantee cpu shielding?

I would be highly obliged if some one could direct me to the right

Many thanks
Siddhartha Jana