Open Paul-St-Young opened 3 years ago
I should add that -b rs
works as intended when each resource set is purely OpenMP
export OMP_NUM_THREAEDS=7; jsrun -n 6 -c 7 -a 1 -b rs -d packed
appropriately binds one thread to each core
You may use qmc-check-affinity to access exact affinity. SMT1 not used?
Describe the bug Nexus' default bind option on Summit is
-b rs
. I observed that-b rs
oversubscribes the cores in a pure MPI run.To Reproduce Steps to reproduce the behavior:
bsub–W 10 –nnodes1 –P $OLCF_PROJECT_ID –Is $SHELL
module load job-step-viewer
Expected behavior All MPI tasks of a resource set are bound to its first core. Command:
export OMP_NUM_THREAEDS=1; jsrun -n 6 -c 7 -a 7 -b rs -d packed
The problem can be solved by using
-b packed:$OMP_NUM_THREADS
instead of-b rs
Command:export OMP_NUM_THREAEDS=1; jsrun -n 6 -c 7 -a 7 -b packed:1 -d packed
Is this a real problem or did I misunderstand
jsrun
?System: