open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,

I run Telemac-2D on a cluster and I'm doing some benchmark tests with a 15000 element mesh. So according to first results, the simulation with cores > 16 is slower than with 12 cores.

Is there a certain rule how many cores to use for a given number of elements?

Best regards,

Clemens

Hello,

This is not very surprising, as 15000 elements is a rather small mesh. However our tests with many more processors on very big meshes show that the speed up can be still interesting up to a few hundreds of points per sub-domain. You can try the Malpasset test case in 2D (26000 elements), which can run in about 4 s on a 12-core machine (about 10 s here at EDF on a 8-core Linux). It could be that clusters are not so optimised.

With best regards,

Jean-Michel Hervouet

Hello Jean-Michel,

so what I understand it is a trial and error procedure: do some simulations for some time steps with different number of processors and see which number is the most suitable for the case.
As you suggested I tried the Malpasset case which takes 15 sec using 8 cores, 10 sec using 12 cores and 9 sec with 16 cores. So these simulations are not so fast as your simulations, nevertheless I'm happy :)

Best regards,

Clemens