Hello,
has anyone had any experience with AMD's 64 core treadripper regarding cfd in Freecad?
cfd and Threadripper
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Re: cfd and Threadripper
I want to have one. I got faster simulations by using multiple cores in openfoam. But you should only use real cores. Running a case by using also the virtual cores on a intel processor was slower, than using only real cores on the same machine. I do not remember, if it is possible to set it directly in FreeCAD. I was setting up my cases with an editor and run them directly using bluecfd on a windows machine using all real cores in parallel. There are extra steps needed to divide the case in partitions and to rejoin the results for postprocessing.
I managed to run one case on two computers in parallel connected over the ethernet network. But it took more time, due to the networking overhead, than using only one of those computers. So my experience is that more cores on one machine do help. But it depends also on the case.
Ulrich
I managed to run one case on two computers in parallel connected over the ethernet network. But it took more time, due to the networking overhead, than using only one of those computers. So my experience is that more cores on one machine do help. But it depends also on the case.
Ulrich
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blindmessenger
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Re: cfd and Threadripper
I have an Amd 6 core. If I calculate with 12 cores it shows all 12 cores at full load in the Task Manager ... I will try again if it is really faster than with 6 real cores ...
I have the impression that with the solver it is important to have a lot of cores, while with meshing it is more important to have a lot of memory. If I set a fine net with cfmesh he sucks up with the complete 48gb ram which I have ..
I have the impression that with the solver it is important to have a lot of cores, while with meshing it is more important to have a lot of memory. If I set a fine net with cfmesh he sucks up with the complete 48gb ram which I have ..
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blindmessenger
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Re: cfd and Threadripper
You're right ... With all 12 cores it is slower than with the 6 real cores ...
Re: cfd and Threadripper
usually, it does not make sense to run CPU intense calculations on HT cores too - sometimes it does however.
There are some articles on when to use HT and when not (just read about what HT actually does already gives you a clue when you can use it properly).
My rule of thumb is: use HT if the processes do have some IO to slow memory (i.e. everything that is not RAM) and not use it otherwise.
So for FE calculations, I usually never use HT. However I found that certain image processing tasks like registration using ITK works slightly faster using HT cores too.
There are some articles on when to use HT and when not (just read about what HT actually does already gives you a clue when you can use it properly).
My rule of thumb is: use HT if the processes do have some IO to slow memory (i.e. everything that is not RAM) and not use it otherwise.
So for FE calculations, I usually never use HT. However I found that certain image processing tasks like registration using ITK works slightly faster using HT cores too.
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blindmessenger
- Posts: 113
- Joined: Mon Dec 03, 2018 3:47 pm
Re: cfd and Threadripper
Net with Base Element Size 0,1mm
Net with Base Element Size 150mm (Meshingtime: 75 sec)
The finer the net, the more RAM is required.
- Fine net.JPG (416.26 KiB) Viewed 1667 times
Net with Base Element Size 150mm (Meshingtime: 75 sec)
- 150mm net.JPG (406.64 KiB) Viewed 1667 times
The finer the net, the more RAM is required.