John Emmas patch for DSP CPU computation.

git-svn-id: http://subversion.jackaudio.org/jack/jack2/trunk/jackmp@4547 0c269be4-1314-0410-8aa9-9f06e86f4224

ChangeLog

@@ -30,11 +30,16 @@ Adrian Knoth
 David Garcia Garzon
 Valerio Pilo
 Chris Caudle
+John Emmas
 
 ---------------------------
   Jackdmp changes log
 ---------------------------
 
+2011-10-10 Stephane Letz  <letz@grame.fr>
+
+	* John Emmas patch for DSP CPU computation.
+
 2011-09-27 Stephane Letz  <letz@grame.fr>
 
 	* Gabriel Beddingfield patch for ALSA driver: error when source is non-native byte-order float.

common/JackEngineControl.cpp

@@ -53,23 +53,37 @@ void JackEngineControl::CalcCPULoad(JackClientInterface** table,
     }
 
     // Store the execution time for later averaging
-    fRollingClientUsecs[fRollingClientUsecsIndex++] = last_cycle_end - fPrevCycleTime;
+    if (last_cycle_end > 0)
+        fRollingClientUsecs[fRollingClientUsecsIndex++] = last_cycle_end - fPrevCycleTime;
     if (fRollingClientUsecsIndex >= JACK_ENGINE_ROLLING_COUNT)
         fRollingClientUsecsIndex = 0;
 
-    // Every so often, recompute the current maximum use over the
-    // last JACK_ENGINE_ROLLING_COUNT client iterations.
-
-    if (++fRollingClientUsecsCnt % fRollingInterval == 0) {
-
+    // Each time we have a full set of iterations, recompute the current
+    // usage from the latest JACK_ENGINE_ROLLING_COUNT client entries.
+    if (fRollingClientUsecsCnt && (fRollingClientUsecsIndex == 0)) {
+        jack_time_t avg_usecs = 0;
         jack_time_t max_usecs = 0;
-        for (int i = 0; i < JACK_ENGINE_ROLLING_COUNT; i++)
+
+        for (int i = 0; i < JACK_ENGINE_ROLLING_COUNT; i++) {
+            avg_usecs += fRollingClientUsecs[i]; // This is really a running
+                                                 // total to be averaged later
             max_usecs = JACK_MAX(fRollingClientUsecs[i], max_usecs);
+        }
 
         fMaxUsecs = JACK_MAX(fMaxUsecs, max_usecs);
-        fSpareUsecs = jack_time_t((max_usecs < fPeriodUsecs) ? fPeriodUsecs - max_usecs : 0);
+
+        if (max_usecs < ((fPeriodUsecs * 95) / 100)) {
+            // Average the values from our JACK_ENGINE_ROLLING_COUNT array
+            fSpareUsecs = (jack_time_t)(fPeriodUsecs - (avg_usecs / JACK_ENGINE_ROLLING_COUNT));
+        } else {
+            // Use the 'worst case' value (or zero if we exceeded 'fPeriodUsecs')
+            fSpareUsecs = jack_time_t((max_usecs < fPeriodUsecs) ? fPeriodUsecs - max_usecs : 0);
+        }
+
         fCPULoad = ((1.f - (float(fSpareUsecs) / float(fPeriodUsecs))) * 50.f + (fCPULoad * 0.5f));
     }
+
+    fRollingClientUsecsCnt++;
 }
 
 void JackEngineControl::ResetRollingUsecs()

common/JackEngineControl.h

@@ -69,12 +69,12 @@ struct SERVER_EXPORT JackEngineControl : public JackShmMem
     bool fVerbose;
 
     // CPU Load
-    jack_time_t fPrevCycleTime;
-    jack_time_t fCurCycleTime;
-    jack_time_t fSpareUsecs;
-    jack_time_t fMaxUsecs;
-    jack_time_t fRollingClientUsecs[JACK_ENGINE_ROLLING_COUNT];
-    int	fRollingClientUsecsCnt;
+    jack_time_t  fPrevCycleTime;
+    jack_time_t  fCurCycleTime;
+    jack_time_t  fSpareUsecs;
+    jack_time_t  fMaxUsecs;
+    jack_time_t  fRollingClientUsecs[JACK_ENGINE_ROLLING_COUNT];
+    unsigned int fRollingClientUsecsCnt;
     int	fRollingClientUsecsIndex;
     int	fRollingInterval;
     float fCPULoad;