MINOR: task: do not try to redistribute the WQ when single-threaded

When running with nbthread=1, we still try to redistribute once, it
fails (new_tid=tid) and leaves the loop. That's just a waste for no
reason. Let's condition the redispatch to the presence of at least
another thread.

diff --git a/src/task.c b/src/task.c
index 8eabb463391475bea6bba22ef772b52af926d615..055f26d221c3e90cb2f72fe2f634822d399a35d2 100644 (file)
--- a/src/task.c
+++ b/src/task.c
@@ -388,7 +388,7 @@ void wake_expired_tasks()
                         * If it's a shared task, see whether we should hand it
                         * to a less loaded thread.
                         */
-                       if (task->tid < 0) {
+                       if (unlikely(task->tid < 0) && global.nbthread > 1) {
                                int attempts = MIN(global.nbthread, 3);
                                while (attempts-- > 0) {
                                        uint new_tid = statistical_prng_range(global.nbthread);