diff --git a/testing/btest/btest.cfg b/testing/btest/btest.cfg
index 5668992b56..b47ff2dddf 100644
--- a/testing/btest/btest.cfg
+++ b/testing/btest/btest.cfg
@@ -14,6 +14,7 @@ MinVersion  = 0.63
 [environment]
 ZEEKPATH=`bash -c %(testbase)s/../../%(build_dir)s/zeek-path-dev`
 HILTI_CXX_COMPILER_LAUNCHER=`f=%(testbase)s/../../%(build_dir)s/CMakeCache.txt && grep -q '^ENABLE_CCACHE:BOOL=true' $f && sed -n 's/^CCACHE_PROGRAM:FILEPATH=\(.*\)$/\1/p' $f`
+HILTI_JIT_PARALLELISM=`bash -c 'echo ${HILTI_JIT_PARALLELISM:-1}'`
 ZEEK_SEED_FILE=%(testbase)s/random.seed
 ZEEK_PLUGIN_PATH=
 TZ=UTC