Multi-Threading Bug on Windows: setting Threads.nthreads() = 6 for using BlackBoxOptim

New to Julia
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1

Hallo,

I am trying to take advantage of Multithreaded and Parallel Function Evaluation of BlackBoxOptim.jl which requires Threads.nthreads() > 2 by using Julia 1.4.1

BlackBoxOptim.jl

Nevertheless on Windows 10 I am not able to set the number of Threads.nthreads() > 1

Following
Multi-Threading (Experimental)

I type the following commands:

WindowsShell
WindowsShell1280×720 62.7 KB

set JULIA_NUM_THREADS=6

It successfully accepts the code.
But when I type

julia> Threads.nthreads()
 1

I will be ever so grateful if you could inform me what I am doing wrong?

Also in VScode I have the option:

Julia: Num Threads
Number of threads to use for Julia processes =6
1 Like
2

after set JULIA_NUM_THREADS=6, start julia in the same command window (by typing julia)

3

That was really simple thanks

My question is why the option in VScode of Num Threads does not work?

4

How can I automatically at the start of Julia force JULIA_NUM_THREADS=6?

Thanks

5

I am using this in startup.jl

ENV["JULIA_NUM_THREADS"] = 6

but I am not working on windows, so I am not sure whether it will work for you that way.

6

Are you using Julia VS Code extension version 0.15.29?

I’m on Windows and in this version setting the extension’s julia.NumThreads setting works.

7

I don’t think that works because that file is loaded (by virtue of it being a julia file) after julia has started.

8

You are right, thanks for the correction. I copied that from some other thread on discourse and never verified whether it works or not. And yes, it does not work.

9

In the upcoming 1.5 release it is possible to use julia --threads=6 for example.

4 Likes
10

Thanks hsm mine julia.NumThreads setting does not work. May be it works for Distributed package with addprocs(). Kristoffer solved my problem:

In the upcoming 1.5 release it is possible to use julia --threads=6 for example.

1 Like