[molpro-user] values for --tuning-mpplat and --tuning-mppspeed
Gershom (Jan) Martin
gershom at weizmann.ac.il
Wed Dec 28 10:39:36 CET 2016
Dear Molpro gurus:
What would be sensible values for --tuning-mpplat and --tuning-mppspeed between cluster nodes with an Infiniband 4-lane QDR (fully nonblocking) interconnect?
What about FDR?
The defaults in the distribution Linux/Intel binary are apparently
--tuning-mpplat 3 and --tuning-mppspeed 1600
The old mpptune.com<http://mpptune.com> script (no longer included with M2015, presumably obsolete) give latencies WAY in excess of this, even when run within a single node.
I tried running an 8-box job (water tetramer CCSD(T)-F12c/cc-pVQZ-F12, no symmetry, 8 processes per box, 2 threads each) with custom parameters
--tuning-mpplat 1 and --tuning-mppspeed 7000
(i.e., close to the theoretical hardware values)
and am seeing about a 10% speedup in wall clock time, but presumably I am living dangerously here, as the true latency and bandwidth reflect software overheads...
On the same question: what values are optimal for running all inside one box?
Many thanks in advance!
*** "Computational quantum chemistry and more" ********* rMBP *************************************
Dr. Gershom (Jan M.L.) Martin | Baroness Thatcher Professor of Chemistry
Department of Organic Chemistry
Weizmann Institute of Science | Kimmelman Building, Room 361 | 76100 Rehovot, ISRAEL
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