Change the number of threads

[cheng-hsiang-chiu]

Hello,

How could I modify the number of threads while running pipeline examples? According to README, the number of threads is defaulted to the number of cores. However, I would like to change the number of threads and see the runtime performance trend. How could I do that? Thank you so much.

[cheng-hsiang-chiu]

Be more specific. I am running tests/test_noinput_pipe.cpp (https://github.com/fastflow/fastflow/blob/master/tests/test_noinput_pipe.cpp) and I would like to test the sample code with different number of threads. How could I do that? Thank you.

[massimotorquati]

Hi, in FastFlow it is not possible to change the number of threads in a pipeline. It is only possible to change (i.e., activate/deactivate at run-time) the workers on a farm.
For an n-stage pipeline, there are n threads. To reduce the number of threads, you can combine pipeline stages by using the ff_comb* building block. However, such an operation has to be performed statically (in the current version).

[cheng-hsiang-chiu]

Thank you so much for the reply. I will try your suggestions in the sample codes.