# How can I make Flux use all my CPUs?

**URL:** <https://discourse.julialang.org/t/how-can-i-make-flux-use-all-my-cpus/21869>\
**Category:** General Usage\
**Created:** [March 14, 2019, 2:09pm UTC](https://discourse.julialang.org/t/how-can-i-make-flux-use-all-my-cpus/21869 "2019-03-14T14:09:54Z")\
**Posts on this page:** 1\
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**Author:** ![jpsamaroo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jpsamaroo/32/46804_2.png) [@jpsamaroo](https://discourse.julialang.org/u/jpsamaroo)\
**Post date:** [March 15, 2019, 1:41pm UTC](https://discourse.julialang.org/t/how-can-i-make-flux-use-all-my-cpus/21869/7 "2019-03-15T13:41:58Z")

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Correct, _Flux_ does not itself support multi-CPU parallelism (yet). However, because it uses OpenBLAS for its BLAS operations (like the rest of Julia), and because OpenBLAS _does_ do multithreading _sometimes_, then you _sometimes_ see multiple CPUs getting used. Whether all 12 of them will get used is up to what BLAS routines are called, and what OpenBLAS thinks is efficient (sometimes adding more CPUs might not help compute something faster, or can even slow things down).

So the bottom line is that you shouldn’t always expect Flux to use 100% of all your available CPUs; for that to be the case requires the right set of circumstances and the “right” calls into BLAS.

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_[View the full topic](https://discourse.julialang.org/t/how-can-i-make-flux-use-all-my-cpus/21869)._