M17: realtime FX mượt — MMCSS Pro Audio + HIGH_PRIORITY_CLASS (JuceFxLoop), GUI tick cadence động 30/200ms (guiBusy), worklet CAP 32->48, track FX gửi input NGAY như master

native_bridge/juce_fx/JuceFxLoop.cpp

@@ -16,6 +16,7 @@
 #endif
 #include <windows.h>
 #include <mmsystem.h>
+#include <avrt.h>
 #endif
 
 #include <algorithm>
@@ -229,6 +230,18 @@ int run_juce_fx_loop(const std::string& jobPath, const std::string& shmName,
 #ifdef _WIN32
     timeBeginPeriod(1);
     SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_HIGHEST);
+    // MMCSS "Pro Audio": Windows đảm bảo quantum + ưu tiên cho thread này khi
+    // CPU cạnh tranh — chống spike deschedule (loopMax 430ms / 5756ms ở log).
+    // AvSetMmThreadCharacteristicsW (Avrt.lib). Process HIGH_PRIORITY_CLASS —
+    // không cần admin (REALTIME_PRIORITY_CLASS cần SeIncreaseBasePriorityPrivilege).
+    DWORD mmTaskIndex = 0;
+    HANDLE hMm = AvSetMmThreadCharacteristicsW(L"Pro Audio", &mmTaskIndex);
+    if (hMm) {
+        SetPriorityClass(GetCurrentProcess(), HIGH_PRIORITY_CLASS);
+        std::cerr << "[JuceFxLoop] MMCSS Pro Audio ok" << std::endl;
+    } else {
+        std::cerr << "[JuceFxLoop] MMCSS unavailable err=" << GetLastError() << std::endl;
+    }
 #endif
 
     // Engine: prepare graph (chain theo fx_chain). sr/block từ job; header là
@@ -501,6 +514,7 @@ int run_juce_fx_loop(const std::string& jobPath, const std::string& shmName,
     guiHost.stop();      // M2: đóng editor (GUI thread) + dừng GUI thread + join
     fxshm::closeShm(v);
 #ifdef _WIN32
+    if (hMm) AvRevertMmThreadCharacteristics(hMm);
     timeEndPeriod(1);
 #endif
     std::cerr << "[JuceFxLoop] exit processed=" << processed << std::endl;