From b0c8495f6c6b9ea5aeb34d4200e8fd3af82609b2 Mon Sep 17 00:00:00 2001
From: Jean Pierre Cimalando <jp-dev@inbox.ru>
Date: Tue, 23 Jun 2020 04:03:35 +0200
Subject: [PATCH] Replace the filled promise queue busy wait with semaphore

---
 src/sfizz/FilePool.cpp | 10 +++++-----
 src/sfizz/FilePool.h   |  1 +
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/sfizz/FilePool.cpp b/src/sfizz/FilePool.cpp
index 65a3b357..2abf3b45 100644
--- a/src/sfizz/FilePool.cpp
+++ b/src/sfizz/FilePool.cpp
@@ -415,10 +415,8 @@ void sfz::FilePool::loadingThread() noexcept
 
         threadsLoading--;
 
-        while (!filledPromiseQueue.try_push(promise)) {
-            DBG("[sfizz] Error enqueuing the promise for " << promise->fileId << " in the filledPromiseQueue");
-            std::this_thread::sleep_for(std::chrono::milliseconds(1));
-        }
+        semFilledPromiseQueueAvailable.wait();
+        filledPromiseQueue.push(promise);
 
         promise.reset();
     } while (1);
@@ -447,8 +445,10 @@ void sfz::FilePool::cleanupPromises() noexcept
     // Remove the promises from the filled queue and put them in a linear
     // storage
     FilePromisePtr promise;
-    while (filledPromiseQueue.try_pop(promise))
+    while (filledPromiseQueue.try_pop(promise)) {
+        semFilledPromiseQueueAvailable.post();
         temporaryFilePromises.push_back(promise);
+    }
 
     auto promiseUsedOnce = [](FilePromisePtr& p) { return p.use_count() == 1; };
     auto moveToClear = [&](FilePromisePtr& p) { return promisesToClear.push_back(p); };
diff --git a/src/sfizz/FilePool.h b/src/sfizz/FilePool.h
index 80e7f8a2..ee81c268 100644
--- a/src/sfizz/FilePool.h
+++ b/src/sfizz/FilePool.h
@@ -268,6 +268,7 @@ private:
 
     atomic_queue::AtomicQueue2<FilePromisePtr, config::maxVoices> promiseQueue;
     atomic_queue::AtomicQueue2<FilePromisePtr, config::maxVoices> filledPromiseQueue;
+    RTSemaphore semFilledPromiseQueueAvailable { config::maxVoices };
     uint32_t preloadSize { config::preloadSize };
     Oversampling oversamplingFactor { config::defaultOversamplingFactor };
     // Signals