# Ideal number of BLAS threads

**URL:** <https://discourse.julialang.org/t/ideal-number-of-blas-threads/79197>\
**Category:** General Usage\
**Tags:** blas, multithreading, linearalgebra\
**Created:** [April 7, 2022, 10:30pm UTC](https://discourse.julialang.org/t/ideal-number-of-blas-threads/79197 "2022-04-07T22:30:16Z")\
**Posts on this page:** 1\
**Showing post:** 10

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**Author:** ![anon28281882](https://avatars.discourse-cdn.com/v4/letter/a/7ab992/32.png) [@anon28281882](https://discourse.julialang.org/u/anon28281882)\
**Post date:** [April 27, 2022, 12:49am UTC](https://discourse.julialang.org/t/ideal-number-of-blas-threads/79197/10 "2022-04-27T00:49:44Z")

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> [@fipelle](#):
>
> I have noticed that on a cluster with 1vCPU per core and a total of 64 cores `BLAS.set_num_threads()` sets a maximum of 32 cores (not 64). Would you please clarify what is the reasoning behind it?

Apart to above suggestions you may also take a look at Julia 1.8 [[BLAS performance testing for Julia 1.8](https://discourse.julialang.org/t/blas-performance-testing-for-julia-1-8/69520)]. I have not followed it recently, however as I understand it currently, there might be some significant changes and automation associated with BLAS and 1.8 release.

@carstenbauer Would BLISBLAS.jl work on Neoverse N1 (Ampere Altra)? I have heard some words that on this particular CPU BLIS might be one of the most favorable options.

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