set default blas num threads to Sys.CPU_THREADS / 2 (#45412)

Set default blas num threads to Sys.CPU_THREADS / 2 in absence of OPENBLAS_NUM_THREADS Co-authored-by: SamuraiAku <61489439+SamuraiAku@users.noreply.github.com> (cherry picked from commit 390503e)
JuliaLang · May 23, 2022 · a02630e · a02630e
1 parent b8943ec
commit a02630e
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/stdlib/LinearAlgebra/src/LinearAlgebra.jl b/stdlib/LinearAlgebra/src/LinearAlgebra.jl
@@ -581,6 +581,10 @@ function __init__()
     end
     # register a hook to disable BLAS threading
     Base.at_disable_library_threading(() -> BLAS.set_num_threads(1))
+
+    if !haskey(ENV, "OPENBLAS_NUM_THREADS")
+        BLAS.set_num_threads(max(1, Sys.CPU_THREADS ÷ 2))
+    end
 end
 
 end # module LinearAlgebra