- scheduler: if an app has only GPU versions,

scale their PFC by 0.1 in credit calculations.
    This reflects the fact that GPU apps are typically less efficient
    (relative to device peak FLOPS) than are CPU apps.
    The actual values from SETI@home and Milkyway are 0.05 and 0.08.


svn path=/trunk/boinc/; revision=24842

checkin_notes

@@ -9181,3 +9181,13 @@ Rom    20 Dec 2011
     samples/vboxwrapper/
         vbox.cpp, .h
         vboxwrapper.cpp
+
+David  20 Dec 2011
+    - scheduler: if an app has only GPU versions,
+        scale their PFC by 0.1 in credit calculations.
+        This reflects the fact that GPU apps are typically less efficient
+        (relative to device peak FLOPS) than are CPU apps.
+        The actual values from SETI@home and Milkyway are 0.05 and 0.08.
+
+    sched/
+        credit.cpp

sched/credit.cpp

@@ -209,6 +209,13 @@ int scale_versions(APP& app, double avg, SCHED_SHMEM* ssp) {
     return 0;
 }
 
+#define DEFAULT_GPU_SCALE   0.1
+// if there are no CPU versions to compare against,
+// multiply pfc_scale of GPU versions by this.
+// This reflects the average lower efficiency of GPU apps compared to CPU apps.
+// The observed values from SETI@home and Milkyway are 0.05 and 0.08.
+// We'll be a little generous and call it 0.1
+
 // Update app version scale factors,
 // and find the min average PFC for each app.
 // Called periodically from the master feeder.
@@ -276,11 +283,11 @@ int update_av_scales(SCHED_SHMEM* ssp) {
                 "CPU avg: %g\n", cpu_info.avg()
             );
             scale_versions(app, cpu_info.avg(), ssp);
-        } else if (gpu_info.nvers_thresh > 1) {
+        } else if (gpu_info.nvers_thresh > 0) {
             log_messages.printf(MSG_NORMAL,
                 "GPU avg: %g\n", gpu_info.avg()
             );
-            scale_versions(app, gpu_info.avg(), ssp);
+            scale_versions(app, gpu_info.avg()*DEFAULT_GPU_SCALE, ssp);
         }
 
     }