Now that we have fine-granularity run queue checking, return check of it to path where we create the thread to avoid lagging effect - this now very nicely modulates the number of created threads, significantly better than old approach... Also removed the '-1' for manager thread in the platform-specific load.c, instead check in common code as the same pattern is required everywhere.

Author: jocke

Diff for: src/linux/load.c

@@ -69,11 +69,6 @@ linux_get_kse_count(void)
     }
     nkse = atoi(p + 1);
 
-    /* The manager thread is currently running, but will not perform any "real" work.
-     * Subtract one from the total number of running KSEs. 
-     */
-    nkse--;
-
     (void) close(fd);
 
     return ((unsigned int) nkse);
@@ -105,10 +100,5 @@ linux_get_runqueue_length(void)
 
    (void) fclose(f);
 
-    /* The manager thread is currently running, but will not perform 
-     * any "real" work. Subtract it from the runqueue size.
-     */
-   runqsz--;
-
    return ((unsigned int) runqsz);
 }

Diff for: src/posix/manager.c

@@ -526,8 +526,8 @@ manager_main(void *unused __attribute__ ((unused)))
 
         dbg_puts("manager is awake");
 
-        dbg_printf("load=%u idle=%u workers=%u max_workers=%u worker_min = %u",
-                   scoreboard.load, scoreboard.idle, scoreboard.count, worker_max, worker_min);
+        dbg_printf("idle=%u workers=%u max_workers=%u worker_min = %u",
+                   scoreboard.idle, scoreboard.count, worker_max, worker_min);
 
         // If no workers available, check if we should create a new one
         if ((scoreboard.idle == 0) && (scoreboard.count > 0) && (pending_thread_create == 0)) // last part required for an extremely unlikely race at startup
@@ -545,15 +545,14 @@ manager_main(void *unused __attribute__ ((unused)))
                 {
                     if (threads_runnable(&current_thread_count) != 0)
                         current_thread_count = 0;
-                    else
-                        current_thread_count--; // decrease by one as we don't want to count the manager thread who 
-                                                // usually will be runnable when testing this...
-                    // TODO: We should instead pass our thread id to thread_runnable() 
 
                     // only start thread if we have less runnable threads than cpus and load allows it
-                    if (current_thread_count < cpu_count)
+                    
+                    if (current_thread_count <= cpu_count) // <= discounts the manager thread
                     {
-                        if (scoreboard.load <= load_max) 
+                        scoreboard.load = get_load_average(); 
+
+                        if (scoreboard.load <= load_max) // <= discounts the manager thread
                         {
                             if (scoreboard.idle == 0) // someone might have become idle during getting thread count etc.
                                 worker_start();
@@ -569,7 +568,7 @@ manager_main(void *unused __attribute__ ((unused)))
                     }
                     else
                     {
-                        dbg_printf("Not spawning worker thread, thread_runnable = %d >= cpu_count = %d", 
+                        dbg_printf("Not spawning worker thread, thread_runnable = %d > cpu_count = %d", 
                                    current_thread_count, cpu_count);
                     }
                 }
@@ -584,8 +583,6 @@ manager_main(void *unused __attribute__ ((unused)))
         {
             if (sem_timedwait_rv == ETIMEDOUT) // Only check for ramp down on the 'timer tick'
             {
-                scoreboard.load = get_load_average(); // update internal stat, avoid doing it in critical path for creating new threads...
-                
                 if (scoreboard.idle > worker_idle_threshold) // only accumulate if there are 'too many' idle threads
                 {
                     worker_idle_seconds_accumulated += scoreboard.idle; // keep track of many idle 'thread seconds' we have

Diff for: src/solaris/load.c

@@ -65,7 +65,7 @@ solaris_get_runqueue_length(void)
     if (previous_updates != 0)
     {
         run_queue = (previous_runque/previous_updates);
-//        dbg_printf("runqueue = %u, updates = %u, ratio = %u \n", previous_runque, previous_updates, run_queue);
+        dbg_printf("runqueue = %u, updates = %u, ratio = %u \n", previous_runque, previous_updates, run_queue);
     }
 
     previous_runque = sysinfo.runque;
@@ -76,9 +76,5 @@ solaris_get_runqueue_length(void)
         return 0;
     }
 
-    /* The manager thread is currently running, but will not perform 
-     * any "real" work. Subtract it from the runqueue size returned.
-     */
-
-    return (run_queue > 0 ? (run_queue - 1) : 0);
+    return run_queue;
 }