Learning Forum

[tbb16]

Hi,

Just wondering why the 18.2 version blocks MPI?? I upgraded from 18.0 which allowed me to utilize the hyper-threading on my PC, but 18.2 doesn't start solving until I drop the cores down to the number of physical cores of my machine.

I'm playing around with explicit analyses so would really like to be able to utilize as many cores as I can on my PC.

I originally tried turning of the firewall etc but it still didn't work, then I saw on another post here that MPI is blocked, so was wondering why the change?

Thanks!!

[peteroznewman]

ANSYS has always limited the solver to using physical cores, and not using two threads per core even when that was available. When I researched how to setup a computer for HPC, ANSYS recommended that hyperthreading be turned off. You can read some more in this post.

[tbb16]

Thanks for your reply. My understanding is that the solver has always been limited to using physical cores when using Mechanical (static problems etc). I am doing explicit analysis which uses the AUTODYN solver, and can easily be distributed across multiple cores. I have always used hyper-threading for explicit and get around 30% increase in performance when doing so (I have tested this extensively). I was just wondering why ANSYS have now blocked the MPI (at least, blocked it on the AUTODYN solver) as I lose that extra 30% performance, which is a lot when simulations run for 5+ hours.