Add thread names on linux

src/queue.c

@@ -6265,10 +6265,18 @@ _dispatch_worker_thread(void *context)
 
 #if HAVE_PTHREAD_SETNAME_NP 
 // pthread thread names are restricted to just 16 characters
-// including NUL. It does not make sense to pass the queue's
-// label as a name.
-pthread_setname_np(pthread_self(), "DispatchWorker");
-#endif
+// including NUL. Truncate the label name from the beginning as it tends 
+// to be more unique at the end.
+size_t label_length = strlen(dq->dq_label); 
+const char * thread_name = dq->dq_label;
+if (label_length > 0) { 
+const size_t max_thread_name_length = 16 - 1; // minus the NUL byte; 
+thread_name = thread_name + (label_length - max_thread_name_length); 
+} else { 
+thread_name = "DispatchWorker";
+}
+pthread_setname_np(pthread_self(), thread_name);
+#endif // HAVE_PTHREAD_SETNAME_NP
 
 errno = 0;
 int rc = setpriority(PRIO_PROCESS, 0, nice);