From: Matthias Maier <tamiko@43-1.org>
Date: Tue, 8 Feb 2022 23:47:14 +0000 (-0600)
Subject: Testsuite: Allow to set deal.II thread pool via TEST_N_THREADS
X-Git-Tag: v9.4.0-rc1~518^2~5
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=41f7992346cd7c81deb156c0f6075c12b51e788c;p=dealii.git

Testsuite: Allow to set deal.II thread pool via TEST_N_THREADS
---

diff --git a/cmake/scripts/run_test.sh b/cmake/scripts/run_test.sh
index 6643c31e4d..f941daa5fe 100644
--- a/cmake/scripts/run_test.sh
+++ b/cmake/scripts/run_test.sh
@@ -44,7 +44,7 @@ case $STAGE in
     ##
 
     # Limit the deal.II thread pool to TEST_THREAD_LIMIT threads.
-    export DEAL_II_NUM_THREADS="${TEST_THREAD_LIMIT}"
+    export TEST_N_THREADS="${TEST_THREAD_LIMIT}"
 
     # Limit the OpenMP pool to two threads.
     export OMP_NUM_THREADS="2"
diff --git a/tests/tests.h b/tests/tests.h
index 5e7a85d8cd..f12d9e1542 100644
--- a/tests/tests.h
+++ b/tests/tests.h
@@ -418,15 +418,26 @@ filter_out_small_numbers(const Number number, const double tolerance)
 
 
 /*
- * If we run 64 tests at the same time on a 64-core system, and
- * each of them runs 64 threads, then we get astronomical loads.
- * Limit concurrency to a fixed (small) number of threads, independent
- * of the core count.
+ * If we run 64 tests at the same time on a 64-core system, and each of
+ * them runs 64 threads, then we get astronomical loads. Limit concurrency
+ * to a fixed (small) number of threads, independent of the core count. The
+ * limit defaults to 3 and can be overriden by the environment variable
+ * TEST_N_THREADS.
  */
 inline unsigned int
 testing_max_num_threads()
 {
-  return 3;
+  if (const char *penv = std::getenv("TEST_N_THREADS"))
+    try
+      {
+        return Utilities::string_to_int(std::string(penv));
+      }
+    catch (...)
+      {
+        return 3;
+      }
+  else
+    return 3;
 }
 
 struct LimitConcurrency