[Bf-committers] OpenMP build needs option for number of threads

IRIE Shinsuke irieshinsuke at yahoo.co.jp
Sat Feb 26 07:18:28 CET 2011


I use Ubuntu 10.10 on Core i7 machine which Hyper-Threading (HT) is

Recently I noticed that the pose-mode repeatedly get into busy waiting
if OpenMP is enabled. Such busy waiting badly disturb our operations.
Perhaps this issue is the same as bugs [#20467] [#20553] [#21344] etc.

By default, OpenMP uses the threads of the same number as logical cores,
but this behavior definitely causes thread conflicts on HT enabled CPU.
We can avoid this problem by setting the number of physical cores to an
environment variable OMP_NUM_THREADS:

$ OMP_NUM_THREADS=4 blender

But I think the number of threads should be configurable at the User
Preferences window. Probably the implementation is easy.



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