I_MPI_PIN_DOMAIN example

4f0drlp7eyj3 — Tue, 11 Sep 2018 23:06:45 GMT

Hi,

I am trying to pin 6 ranks on a dual-socket (12 cores per socket) node, with 4 OpenMP threads per MPI rank. I set I_MPI_PIN_DOMAIN=omp:compact, but I get this I_MPI_DEBUG output:

[0] MPI startup(): 0 14563 n2470 {0,1,12,13}

[0] MPI startup(): 1 14564 n2470 {2,3,14,15}

[0] MPI startup(): 2 14565 n2470 {4,5,16,17}

[0] MPI startup(): 3 14566 n2470 {6,7,18,19}

[0] MPI startup(): 4 14567 n2470 {8,9,20,21}

[0] MPI startup(): 5 14568 n2470 {10,11,22,23}

I would have expected

[0] MPI startup(): 0 14563 n2470 {0,1,2,3}
[0] MPI startup(): 1 14564 n2470 {4,5,6,7}
[0] MPI startup(): 2 14565 n2470 {8,9,10,11}
[0] MPI startup(): 3 14566 n2470 {12,13,14,15}
[0] MPI startup(): 4 14567 n2470 {16,17,18,19}
[0] MPI startup(): 5 14568 n2470 {20,21,22,23}

Intel Parallel Studio Cluster edition 2017 update 5. Am I setting something incorrectly, or is this a behavior to protect performance against myself?

Thanks! - Chris

OK, never mind! I see I hadn

4f0drlp7eyj3 — Wed, 12 Sep 2018 16:58:02 GMT

OK, never mind! I see I hadn't accounted for the logical-to-physical core mapping. All makes sense now.

topic I_MPI_PIN_DOMAIN example in Intel® MPI Library

I_MPI_PIN_DOMAIN example

OK, never mind! I see I hadn