To use sched_setaffinity to make the current process run on core 7 you do this: cpu_set_t my_set; /* Define your cpu_set bit mask. */ CPU_ZERO(&my_set); /* Initialize it all to 0, i.e. no CPUs selected. */ CPU_SET(7, &my_set); /* set the bit that represents core 7. */ sched_setaffinity(0, sizeof(cpu_set_t), &my_set); /* Set affinity of tihs … Read more
orterun (the Open MPI SPMD/MPMD launcher; mpirun/mpiexec are just symlinks to it) has some support for process binding but it is not flexible enough to allow you to bind two processes per core. You can try with -bycore -bind-to-core but it will err when all cores already have one process assigned to them. But there … Read more
You need to use sched_setaffinity(2). For example, to run on CPUs 0 and 2 only: #define _GNU_SOURCE #include <sched.h> cpu_set_t mask; CPU_ZERO(&mask); CPU_SET(0, &mask); CPU_SET(2, &mask); int result = sched_setaffinity(0, sizeof(mask), &mask); (0 for the first parameter means the current process, supply a PID if it’s some other process you want to control). See also … Read more
This is a wrapper I’ve made to make my life easier. Its effect is that the calling thread gets “stuck” to the core with id core_id: // core_id = 0, 1, … n-1, where n is the system’s number of cores int stick_this_thread_to_core(int core_id) { int num_cores = sysconf(_SC_NPROCESSORS_ONLN); if (core_id < 0 || core_id … Read more