place work-stealing queue indices on different cache lines to avoid f…

…alse-sharing
JuliaLang · Jan 22, 2024 · 1b21a32 · 1b21a32
1 parent 4d26be0
commit 1b21a32
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/src/work-stealing-queue.h b/src/work-stealing-queue.h
@@ -34,11 +34,14 @@ static inline ws_array_t *create_ws_array(size_t capacity, int32_t eltsz) JL_NOT
     return a;
 }
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wc11-extensions"
 typedef struct {
     _Atomic(int64_t) top;
-    _Atomic(int64_t) bottom;
+    _Alignas(128) _Atomic(int64_t) bottom; // put on a separate cache line. conservatively estimate cache line size as 128 bytes
     _Atomic(ws_array_t *) array;
 } ws_queue_t;
+#pragma GCC diagnostic pop
 
 static inline ws_array_t *ws_queue_push(ws_queue_t *q, void *elt, int32_t eltsz) JL_NOTSAFEPOINT
 {