Hi, 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: http://www.kernel.org/doc/man-pages/online/pages/man7/cpuset.7.html ] 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 /dev/cpuset/socket1/tasks 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); system(str); ------------------------------------------------------ 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 direction. Many thanks Sincerely Siddhartha Jana
