yade-users team mailing list archive

[Bruno Chareyre <question244277@xxxxxxxxxxxxxxxxxxxxx>]

Question #244277 on Yade changed:
https://answers.launchpad.net/yade/+question/244277

    Status: Open => Answered

Bruno Chareyre proposed the following answer:
I observed that if I run -jN when the number of available cores is >N, the cores that are effectively used are always changing during the simulation. For -j2 for instance, it will use (1,4), (2,3), (4,7), etc. randomly.
Could it be that it adds big overhead when 32 simulations are sharing 64 threads and exchanging them all the time (wich needs, I guess, a lot of cache update)?
Is it the reason for the "affinity" option, that I don't clearly understood yet?

What happens with variants like below?
yade-batch -j1 --job-threads=2 file.table file.py
yade-batch -j2 --job-threads=2 file.table file.py
yade-batch -j4 --job-threads=2 file.table file.py
etc.
Also interesting:
yade-batch -j16 --job-threads=1 file.table file.py

How did you know the "--job-threads" option? I didn't know it and I don't see it in the documentation.
I can grep it in the source code though, if it really works we should mention it in user manual and list it in yade -h.

-- 
You received this question notification because you are a member of
yade-users, which is an answer contact for Yade.