From b6d2434909f15abeca03bb9b68333f5ff670ce9e Mon Sep 17 00:00:00 2001
From: Kristoffer Carlsson <kcarlsson89@gmail.com>
Date: Tue, 20 Sep 2022 08:07:35 +0200
Subject: [PATCH] set number of openblas threads to 1 while precompiling
 (#46792)

---
 base/loading.jl | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/base/loading.jl b/base/loading.jl
index 433c7c5521c69..81919dfea0770 100644
--- a/base/loading.jl
+++ b/base/loading.jl
@@ -1684,12 +1684,14 @@ function create_expr_cache(pkg::PkgId, input::String, output::String, concrete_d
     deps_eltype = sprint(show, eltype(concrete_deps); context = :module=>nothing)
     deps = deps_eltype * "[" * join(deps_strs, ",") * "]"
     trace = isassigned(PRECOMPILE_TRACE_COMPILE) ? `--trace-compile=$(PRECOMPILE_TRACE_COMPILE[])` : ``
-    io = open(pipeline(`$(julia_cmd()::Cmd) -O0
-                       --output-ji $output --output-incremental=yes
-                       --startup-file=no --history-file=no --warn-overwrite=yes
-                       --color=$(have_color === nothing ? "auto" : have_color ? "yes" : "no")
-                       $trace
-                       -`, stderr = internal_stderr, stdout = internal_stdout),
+    io = open(pipeline(addenv(`$(julia_cmd()::Cmd) -O0
+                              --output-ji $output --output-incremental=yes
+                              --startup-file=no --history-file=no --warn-overwrite=yes
+                              --color=$(have_color === nothing ? "auto" : have_color ? "yes" : "no")
+                              $trace
+                              -`,
+                              "OPENBLAS_NUM_THREADS" => 1),
+                       stderr = internal_stderr, stdout = internal_stdout),
               "w", stdout)
     # write data over stdin to avoid the (unlikely) case of exceeding max command line size
     write(io.in, """