Implement jack_max_cpu_load

Signed-off-by: falkTX <falktx@falktx.com>

common/JackAPI.cpp

@@ -195,6 +195,7 @@ extern "C"
                                         jack_time_t    *next_usecs,
                                         float          *period_usecs);
     LIB_EXPORT float jack_cpu_load(jack_client_t *client);
+    LIB_EXPORT float jack_max_cpu_load(jack_client_t *client);
     LIB_EXPORT jack_native_thread_t jack_client_thread_id(jack_client_t *);
     LIB_EXPORT void jack_set_error_function(print_function);
     LIB_EXPORT void jack_set_info_function(print_function);
@@ -1457,6 +1458,20 @@ LIB_EXPORT float jack_cpu_load(jack_client_t* ext_client)
     }
 }
 
+LIB_EXPORT float jack_max_cpu_load(jack_client_t* ext_client)
+{
+    JackGlobals::CheckContext("jack_max_cpu_load");
+
+    JackClient* client = (JackClient*)ext_client;
+    if (client == NULL) {
+        jack_error("jack_max_cpu_load called with a NULL client");
+        return 0.0f;
+    } else {
+        JackEngineControl* control = GetEngineControl();
+        return (control ? control->fMaxCPULoad : 0.0f);
+    }
+}
+
 LIB_EXPORT jack_native_thread_t jack_client_thread_id(jack_client_t* ext_client)
 {
     JackGlobals::CheckContext("jack_client_thread_id");

common/JackEngineControl.cpp

@@ -83,6 +83,7 @@ void JackEngineControl::CalcCPULoad(JackClientInterface** table,
         }
 
         fCPULoad = ((1.f - (float(fSpareUsecs) / float(fPeriodUsecs))) * 50.f + (fCPULoad * 0.5f));
+        fMaxCPULoad = 1.f - (float(fMaxUsecs) / float(fPeriodUsecs));
     }
 
     fRollingClientUsecsCnt++;

common/JackEngineControl.h

@@ -76,9 +76,10 @@ struct SERVER_EXPORT JackEngineControl : public JackShmMem
     jack_time_t fMaxUsecs;
     jack_time_t fRollingClientUsecs[JACK_ENGINE_ROLLING_COUNT];
     unsigned int fRollingClientUsecsCnt;
-    int	fRollingClientUsecsIndex;
-    int	fRollingInterval;
+    int fRollingClientUsecsIndex;
+    int fRollingInterval;
     float fCPULoad;
+    float fMaxCPULoad;
 
     // For OSX thread
     UInt64 fPeriod;
@@ -124,6 +125,7 @@ struct SERVER_EXPORT JackEngineControl : public JackShmMem
         strncpy(fServerName, server_name, sizeof(fServerName));
         fServerName[sizeof(fServerName) - 1] = 0;
         fCPULoad = 0.f;
+        fMaxCPULoad = 0.f;
         fPeriod = 0;
         fComputation = 0;
         fConstraint = 0;

common/jack/jack.h

@@ -704,6 +704,14 @@ int jack_engine_takeover_timebase (jack_client_t *) JACK_OPTIONAL_WEAK_DEPRECATE
  */
 float jack_cpu_load (jack_client_t *client) JACK_OPTIONAL_WEAK_EXPORT;
 
+/**
+ * @return the current maximum CPU load used by JACK.  This is a running
+ * average of the time it takes to execute a full process cycle for
+ * all clients as a percentage of the real time available per cycle
+ * determined by the buffer size and sample rate.
+ */
+float jack_max_cpu_load (jack_client_t *client) JACK_OPTIONAL_WEAK_EXPORT;
+
 /**@}*/
 
 /**