Similar to some other micro-optimizations, don't keep recreating a new

list of messages to dispatch in MessageQueue -- create it once as a member
variable and reuse.

Also tweaked stream and output buffer sizes.

src/contrib/alsaout/AlsaOut.cpp

@@ -35,7 +35,7 @@
 #include "AlsaOut.h"
 #include <core/sdk/constants.h>
 
-#define BUFFER_COUNT 32
+#define BUFFER_COUNT 16
 #define PCM_ACCESS_TYPE SND_PCM_ACCESS_RW_INTERLEAVED
 #define PCM_FORMAT SND_PCM_FORMAT_FLOAT_LE
 

src/contrib/coreaudioout/CoreAudioOut.cpp

@@ -36,7 +36,7 @@
 #include <core/sdk/constants.h>
 #include <iostream>
 
-#define BUFFER_COUNT 32
+#define BUFFER_COUNT 16
 
 using namespace musik::core::sdk;
 

src/contrib/waveout/WaveOut.cpp

@@ -37,7 +37,7 @@
 #include <core/sdk/constants.h>
 
 #define MAX_VOLUME 0xFFFF
-#define MAX_BUFFERS_PER_OUTPUT 32
+#define MAX_BUFFERS_PER_OUTPUT 16
 
 using LockT = std::unique_lock<std::recursive_mutex>;
 

src/core/audio/Stream.h

@@ -51,12 +51,12 @@ namespace musik { namespace core { namespace audio {
         using IDecoder = musik::core::sdk::IDecoder;
 
         public:
-            /* note that most output devices manage 16-32 buffers internally,
-            so, by default, let's allocate 48 buffers worth of contiguous
+            /* note that most output devices manage 16 buffers internally,
+            so, by default, let's allocate 32 buffers worth of contiguous
             memory. if we need more buffers they will be allocated dynamically */
             static StreamPtr Create(
                 int samplesPerChannel = 2048,
-                int bufferCount = 48,
+                int bufferCount = 32,
                 unsigned int options = 0);
 
         private:

src/core/runtime/MessageQueue.cpp

@@ -72,7 +72,6 @@ void MessageQueue::Dispatch() {
         system_clock::now().time_since_epoch());
 
     using Iterator = std::list<EnqueuedMessage*>::iterator;
-    std::list<EnqueuedMessage*> toDispatch;
 
     {
         LockT lock(this->queueMutex);
@@ -88,7 +87,7 @@ void MessageQueue::Dispatch() {
             EnqueuedMessage *m = (*it);
 
             if (now >= m->time) {
-                toDispatch.push_back(m);
+                this->dispatch.push_back(m);
                 it = this->queue.erase(it);
             }
             else {
@@ -99,12 +98,14 @@ void MessageQueue::Dispatch() {
 
     /* dispatch outside of the critical section */
 
-    Iterator it = toDispatch.begin();
-    while (it != toDispatch.end()) {
+    Iterator it = this->dispatch.begin();
+    while (it != this->dispatch.end()) {
         this->Dispatch((*it)->message);
         delete *it;
         it++;
     }
+
+    this->dispatch.clear();
 }
 
 int MessageQueue::Remove(IMessageTarget *target, int type) {

src/core/runtime/MessageQueue.h

@@ -63,6 +63,7 @@ namespace musik { namespace core { namespace runtime {
 
             std::mutex queueMutex;
             std::list<EnqueuedMessage*> queue;
+            std::list<EnqueuedMessage*> dispatch;
             std::condition_variable_any waitForDispatch;
 
             void Dispatch(IMessagePtr message);