Raise number of threads used by GASNet by default + add warning if ex…

…ceeded --- Signed-off-by: Brad Chamberlain <bradcray@users.noreply.github.com>
chapel-lang · Dec 21, 2024 · c96fc9d · c96fc9d
1 parent 2cfd1a2
commit c96fc9d
Show file tree

Hide file tree

Showing 2 changed files with 12 additions and 2 deletions.
diff --git a/runtime/src/tasks/qthreads/tasks-qthreads.c b/runtime/src/tasks/qthreads/tasks-qthreads.c
@@ -502,7 +502,17 @@ static void setupAvailableParallelism(int32_t maxThreads) {
     if (hwpar > 0) {
         // Limit the parallelism to the maximum imposed by the comm layer.
         if (0 < maxThreads && maxThreads < hwpar) {
-            hwpar = maxThreads;
+          if (chpl_nodeID == 0) {
+            char msg[1024];
+            snprintf(msg, sizeof(msg),
+                     "The CHPL_COMM setting is limiting the number of threads "
+                     "to %d, rather than the hardware's preference of %d.  "
+                     "If using CHPL_COMM=gasnet, set 'GASNET_MAX_THREADS' to "
+                     "a higher number in your environment to address this.\n",
+                     maxThreads, hwpar);
+            chpl_warning(msg, 0, 0);
+          }
+          hwpar = maxThreads;
         }
 
         //

diff --git a/third-party/gasnet/Makefile b/third-party/gasnet/Makefile
@@ -135,7 +135,7 @@ gasnet-config: FORCE
 	mkdir -p $(GASNET_BUILD_DIR)
 	cd $(GASNET_SUBDIR) && ./Bootstrap -T
 	$(XTRA_CONFIG_COMMAND)
-	$(ENSURE_GASNET_COMPATIBLE_COMPILER) cd $(GASNET_BUILD_DIR) && $(CHPL_GASNET_ENV_VARS) $(GASNET_SUBDIR)/$(CHPL_GASNET_CFG_SCRIPT) --prefix=$(GASNET_INSTALL_DIR) $(CHPL_GASNET_CFG_OPTIONS) --disable-seq --enable-par --disable-parsync $(CHPL_GASNET_CFG_OPTIONS)
+	$(ENSURE_GASNET_COMPATIBLE_COMPILER) cd $(GASNET_BUILD_DIR) && $(CHPL_GASNET_ENV_VARS) $(GASNET_SUBDIR)/$(CHPL_GASNET_CFG_SCRIPT) --prefix=$(GASNET_INSTALL_DIR) --disable-seq --enable-par --disable-parsync --with-max-pthreads-per-node=65535 $(CHPL_GASNET_CFG_OPTIONS)
 
 gasnet-build: FORCE
 	$(ENSURE_GASNET_COMPATIBLE_COMPILER) cd $(GASNET_BUILD_DIR) && $(MAKE) all