Fixed MusE failing with non-RT kernel.

Fixed dummy audio thread not running FIFO with RT kernel.

4 files changed, 61 insertions, 19 deletions

diff --git a/muse2/muse/app.cpp b/muse2/muse/app.cpp
index 55f840b6..c1e86a2c 100644
--- a/muse2/muse/app.cpp
+++ b/muse2/muse/app.cpp
@@ -1246,6 +1246,11 @@ MusE::MusE(int argc, char** argv) : QMainWindow()
       panicToolbar->setObjectName("Panic");
       panicToolbar->addAction(panicAction);
 
+      
+      //rlimit lim;
+      //getrlimit(RLIMIT_RTPRIO, &lim);
+      //printf("RLIMIT_RTPRIO soft:%d hard:%d\n", lim.rlim_cur, lim.rlim_max);    // Reported 80, 80 even with non-RT kernel.
+      
       if (realTimePriority < sched_get_priority_min(SCHED_FIFO))
             realTimePriority = sched_get_priority_min(SCHED_FIFO);
       else if (realTimePriority > sched_get_priority_max(SCHED_FIFO))
diff --git a/muse2/muse/driver/dummyaudio.cpp b/muse2/muse/driver/dummyaudio.cpp
index f4a00b4e..d251c79f 100644
--- a/muse2/muse/driver/dummyaudio.cpp
+++ b/muse2/muse/driver/dummyaudio.cpp
@@ -411,38 +411,54 @@ static void* dummyLoop(void* ptr)
 
 //void DummyAudioDevice::start()
 void DummyAudioDevice::start(int priority)
-      {
-      //realTimePriority = priority;
+{
       _realTimePriority = priority;
       pthread_attr_t* attributes = 0;
 
-      //if (priority) {
-      if (realTimeScheduling && priority > 0) {
+      if (realTimeScheduling && _realTimePriority > 0) {
             attributes = (pthread_attr_t*) malloc(sizeof(pthread_attr_t));
             pthread_attr_init(attributes);
 
             if (pthread_attr_setschedpolicy(attributes, SCHED_FIFO)) {
-                  printf("cannot set FIFO scheduling class for RT thread\n");
+                  printf("cannot set FIFO scheduling class for dummy RT thread\n");
                   }
             if (pthread_attr_setscope (attributes, PTHREAD_SCOPE_SYSTEM)) {
-                  printf("Cannot set scheduling scope for RT thread\n");
+                  printf("Cannot set scheduling scope for dummy RT thread\n");
+                  }
+            // p4.0.16 Dummy was not running FIFO because this is needed.
+            if (pthread_attr_setinheritsched(attributes, PTHREAD_EXPLICIT_SCHED)) {
+                  printf("Cannot set setinheritsched for dummy RT thread\n");
                   }
+                  
             struct sched_param rt_param;
             memset(&rt_param, 0, sizeof(rt_param));
             rt_param.sched_priority = priority;
             if (pthread_attr_setschedparam (attributes, &rt_param)) {
-                  printf("Cannot set scheduling priority %d for RT thread (%s)\n",
+                  printf("Cannot set scheduling priority %d for dummy RT thread (%s)\n",
                      priority, strerror(errno));
                   }
             }
       
-      //pthread_attr_t* attributes = (pthread_attr_t*) malloc(sizeof(pthread_attr_t));
-      //pthread_attr_init(attributes);
-      if (pthread_create(&dummyThread, attributes, ::dummyLoop, this))
-            perror("creating thread failed:");
-      if (priority)
+      int rv = pthread_create(&dummyThread, attributes, ::dummyLoop, this); 
+      if(!dummyThread)
+      {  
+        // p4.0.16: realTimeScheduling is unreliable. It is true even in some clearly non-RT cases.
+        // I cannot seem to find a reliable answer to the question of "are we RT or not".
+        // MusE was failing with a stock kernel because of PTHREAD_EXPLICIT_SCHED.
+        // So we'll just have to try again without attributes.
+        if (realTimeScheduling && _realTimePriority > 0) 
+          rv = pthread_create(&dummyThread, NULL, ::dummyLoop, this); 
+      }
+      
+      if(rv || !dummyThread)
+          fprintf(stderr, "creating dummy audio thread failed: %s\n", strerror(rv));
+
+      if (attributes)                      // p4.0.16
+      {
         pthread_attr_destroy(attributes);
+        free(attributes);
       }
+}
 
 void DummyAudioDevice::stop ()
       {
diff --git a/muse2/muse/main.cpp b/muse2/muse/main.cpp
index fccf801d..cf271ace 100644
--- a/muse2/muse/main.cpp
+++ b/muse2/muse/main.cpp
@@ -381,7 +381,15 @@ int main(int argc, char* argv[])
       else
             realTimeScheduling = audioDevice->isRealtime();
 
+      
+      // What unreliable nonsense. With Jack2 this reports true even if it is not running realtime. 
+      // Jack says: "Cannot use real-time scheduling (RR/10)(1: Operation not permitted)". The kernel is non-RT.
+      // I cannot seem to find a reliable answer to the question, even with dummy audio and system calls.
+      //if (debugMsg) 
+      //  printf("realTimeScheduling:%d\n", realTimeScheduling);
+
       useJackTransport.setValue(true);
+      
       // setup the prefetch fifo length now that the segmentSize is known
       // Changed by Tim. p3.3.17
       // Changed to 4 *, JUST FOR TEST!!!
diff --git a/muse2/muse/thread.cpp b/muse2/muse/thread.cpp
index 444d5219..8e89a862 100644
--- a/muse2/muse/thread.cpp
+++ b/muse2/muse/thread.cpp
@@ -63,7 +63,8 @@ void Thread::start(int prio, void* ptr)
 //      pthread_mutex_lock(&lock);
 
 
-      if (_realTimePriority) {
+      //if (_realTimePriority) {
+      if (realTimeScheduling && _realTimePriority > 0) {                        // p4.0.16
             attributes = (pthread_attr_t*) malloc(sizeof(pthread_attr_t));
             pthread_attr_init(attributes);
 
@@ -98,14 +99,26 @@ void Thread::start(int prio, void* ptr)
       */
 
 
-      int rv;
-      if ((rv = pthread_create(&thread, attributes, ::loop, this))) 
+      int rv = pthread_create(&thread, attributes, ::loop, this); 
+      if(!thread)
       {
-            fprintf(stderr, "creating thread <%s> failed: %s\n",
-               _name, strerror(rv));
-            thread = 0;
+        // p4.0.16: realTimeScheduling is unreliable. It is true even in some clearly non-RT cases.
+        // I cannot seem to find a reliable answer to the question of "are we RT or not".
+        // MusE was failing with a stock kernel because of PTHREAD_EXPLICIT_SCHED.
+        // So we'll just have to try again without attributes.
+        if (realTimeScheduling && _realTimePriority > 0) 
+          rv = pthread_create(&thread, NULL, ::loop, this); 
       }
 
+      if(rv || !thread)
+          fprintf(stderr, "creating thread <%s> failed: %s\n", _name, strerror(rv));
+
+      if (attributes)                      // p4.0.16
+      {
+        pthread_attr_destroy(attributes);
+        free(attributes);
+      }
+      
       //undoSetuid();
       }
 
@@ -316,7 +329,7 @@ void Thread::loop()
       if (debugMsg)
             printf("Thread <%s, id %p> has %s priority %d\n",
                _name, (void *)pthread_self(), policy == SCHED_FIFO ? "SCHED_FIFO" : "SCHED_OTHER",
-                _realTimePriority);
+                policy == SCHED_FIFO ? _realTimePriority : 0);
 
 
 //      pthread_mutex_lock(&lock);