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

app/static/js/app.jsx

@@ -25713,34 +25713,20 @@ const App = () => {
         }
         if (d.type !== 'in') return;
         // Burst 4 block (1024 mẫu) → tách 4 WS frame 512 floats → bridge batch 4.
-        // Pace 1 burst/21ms (giống master) — tránh dồn frame sau stall làm tràn ring.
-        entry.inQueue.push(d);
-        const pump = () => {
-          if (!entry.inQueue.length) return;
-          const now = Date.now();
-          while (entry.inQueue.length && now - entry.lastInSent >= FXRT_BURST_MS) {
-            entry.lastInSent = now;
-            const dd = entry.inQueue.shift();
-            if (entry.ws && entry.ws.readyState === 1) {
-              try {
-                const f = new Float32Array(dd.data);
-                if (f.length > 512) {
-                  for (let i = 0; i < f.length; i += 512) entry.ws.send(f.slice(i, i + 512).buffer);
-                } else {
-                  entry.ws.send(dd.data);
-                }
-              } catch (e) {}
+        // Gửi NGAY (không pace setTimeout) như master path (proven): worklet đã
+        // pace 1 burst/21.33ms theo đồng hồ audio; timer main-thread bận/trễ →
+        // input gửi trễ → engine chỉ sản xuất khi có input → cushion cạn →
+        // crackle. Burst sau stall: engine hấp thụ (in ring 4 slot, drop-oldest).
+        if (entry.ws && entry.ws.readyState === 1) {
+          try {
+            const f = new Float32Array(d.data);
+            if (f.length > 512) {
+              for (let i = 0; i < f.length; i += 512) entry.ws.send(f.slice(i, i + 512).buffer);
+            } else {
+              entry.ws.send(d.data);
             }
-          }
-          if (entry.inQueue.length) {
-            if (entry.pumpTimer) clearTimeout(entry.pumpTimer);
-            entry.pumpTimer = setTimeout(pump, Math.max(1, FXRT_BURST_MS - (now - entry.lastInSent)));
-          } else if (entry.pumpTimer) {
-            clearTimeout(entry.pumpTimer);
-            entry.pumpTimer = null;
-          }
-        };
-        pump();
+          } catch (e) {}
+        }
       };
     } catch (e) {
       console.warn('[FX RT track] setup fail', trackId, path, e);

app/static/js/app.precompiled.js

@@ -400,7 +400,7 @@ if(fxRt.warm)fxRtStop(true);// Token chống race bypass: user bấm PWR/Bypass
 // node → bypass vô hiệu. Mỗi fxRtStop() bump startToken → mọi checkpoint
 // dưới đây thấy mismatch → hủy session vừa tạo, không nối node.
 const token=++fxRt.startToken;fxRt.starting=true;const ctx=getAudioContext();if(!ctx||!ctx.audioWorklet||!masterBus||!masterBus.output||!masterBus.analyser||!masterBus.masterFxGain||!masterBus.masterFxDryGain)return;const chainPayload=chain.map(s=>s.type==='vst3'?{type:'vst3',path:s.path,name:s.name||s.path,preset_b64:s.preset_b64||'',bypass:!!s.bypass||!!(window.currentMasteringSettings||{}).vstBypass}:{type:'builtin',id:s.type,params:s.params&&Object.keys(s.params).length?s.params:{},bypass:!!s.bypass});let st;try{st=await window.SonicAPI.fxRealtimeStart({fx_chain:chainPayload,sample_rate:ctx.sampleRate||44100});}catch(e){console.warn('[FX RT] start fail:',e);showToast('Không khởi động VST FX realtime: '+(e.message||e),'warning');fxRt.starting=false;return;}if(token!==fxRt.startToken){// Bypass/stop giữa lúc engine đang load chain — hủy session vừa tạo.
-console.warn('[FX RT] start cancelled mid-flight — session stopped');try{window.SonicAPI.fxRealtimeStop({session_id:st.session_id}).catch(()=>{});}catch(e2){}fxRt.starting=false;return;}fxRt.sessionId=st.session_id;fxRtGuiPushShm();try{await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202609061138`);if(token!==fxRt.startToken){fxRt.starting=false;return;}fxRt.node=new AudioWorkletNode(ctx,'sf-fx-realtime',{numberOfInputs:1,numberOfOutputs:1,outputChannelCount:[2]});const u=new URL(API_BASE_URL);const wsProto=u.protocol==='https:'?'wss://':'ws://';// WS to 'localhost' bi tre ~300ms: Chromium thu ::1 truoc (Windows khong
+console.warn('[FX RT] start cancelled mid-flight — session stopped');try{window.SonicAPI.fxRealtimeStop({session_id:st.session_id}).catch(()=>{});}catch(e2){}fxRt.starting=false;return;}fxRt.sessionId=st.session_id;fxRtGuiPushShm();try{await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202609062020`);if(token!==fxRt.startToken){fxRt.starting=false;return;}fxRt.node=new AudioWorkletNode(ctx,'sf-fx-realtime',{numberOfInputs:1,numberOfOutputs:1,outputChannelCount:[2]});const u=new URL(API_BASE_URL);const wsProto=u.protocol==='https:'?'wss://':'ws://';// WS to 'localhost' bi tre ~300ms: Chromium thu ::1 truoc (Windows khong
 // co listener IPv6 -> SYN hang ~2s) roi moi fallback 127.0.0.1. Dung
 // thang 127.0.0.1 (loopback) -> WS open ~5ms. Server chap nhan loopback.
 const wsHost=u.hostname==='localhost'||u.hostname==='::1'?'127.0.0.1'+(u.port?':'+u.port:''):u.host;const tok=localStorage.getItem('sonic_token')||'';const wsUrl=`${wsProto}${wsHost}${st.ws_url}${tok?'?token='+encodeURIComponent(tok):''}`;const ws=new WebSocket(wsUrl);fxRt.ws=ws;ws.binaryType='arraybuffer';ws.onopen=()=>{if(token!==fxRt.startToken){try{ws.close();}catch(e){}fxRt.starting=false;return;}fxRt.active=true;fxRt.flushing=false;fxRt.starting=false;fxRt.inQueue=[];// bỏ audio stale sản xuất trước khi WS open (~4s load VST) — hết lag khởi đầu
@@ -2169,14 +2169,17 @@ fxRtTrackReconcile(trackId,node,track);}catch(e){console.warn('rebuildTrackFxGra
 // Cần activeTrackNodesRef/isPlayingRef. Session giống master (fxRtStart):
 // fetch start → AudioWorkletNode 'sf-fx-realtime' → WS; WS open → splice
 // worklet vào chain hiện tại (đọc mods MỚI NHẤT — an toàn với rebuild).
-const fxRtTrackStart=async(trackId,track,path)=>{const key=trackId+':'+path;const chain=fxRtTrackChain(track);if(!chain.length)return;if(fxRtTracks[key]){if(!fxRtTracks[key].node||fxRtTracks[key].node.context!==getAudioContext())fxRtTrackStop(trackId,path,true);else return;}const ctx=getAudioContext();if(!ctx||!ctx.audioWorklet)return;const chainPayload=chain.map(s=>s.type==='vst3'?{type:'vst3',path:s.path,name:s.name||s.path,preset_b64:s.preset_b64||'',bypass:!!s.bypass||!!(track&&track.vstFxBypass)}:{type:'builtin',id:s.type,params:s.params&&Object.keys(s.params).length?s.params:{},bypass:!!s.bypass});let st;try{st=await window.SonicAPI.fxRealtimeStart({fx_chain:chainPayload,sample_rate:ctx.sampleRate||44100});}catch(e){console.warn('[FX RT track] start fail',trackId,path,e);return;}const entry={sessionId:st.session_id,ws:null,node:null,ready:false,path,spliced:null,chainKey:fxRtTrackChainKey(chain)+'|vb:'+(track&&track.vstFxBypass?'1':'0'),paramsBySlot:chain.map(s=>fxRtEntryParams(s,null)),inQueue:[],pumpTimer:null,lastInSent:0,flushing:false,flushTimer:null};fxRtTracks[key]=entry;fxRtGuiPushShm();try{await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202609061138`);const node=new AudioWorkletNode(ctx,'sf-fx-realtime',{numberOfInputs:1,numberOfOutputs:1,outputChannelCount:[2]});entry.node=node;const u=new URL(API_BASE_URL);const wsProto=u.protocol==='https:'?'wss://':'ws://';// WS to 'localhost' bi tre ~300ms (Chromium thu ::1 truoc roi fallback) - dung 127.0.0.1
+const fxRtTrackStart=async(trackId,track,path)=>{const key=trackId+':'+path;const chain=fxRtTrackChain(track);if(!chain.length)return;if(fxRtTracks[key]){if(!fxRtTracks[key].node||fxRtTracks[key].node.context!==getAudioContext())fxRtTrackStop(trackId,path,true);else return;}const ctx=getAudioContext();if(!ctx||!ctx.audioWorklet)return;const chainPayload=chain.map(s=>s.type==='vst3'?{type:'vst3',path:s.path,name:s.name||s.path,preset_b64:s.preset_b64||'',bypass:!!s.bypass||!!(track&&track.vstFxBypass)}:{type:'builtin',id:s.type,params:s.params&&Object.keys(s.params).length?s.params:{},bypass:!!s.bypass});let st;try{st=await window.SonicAPI.fxRealtimeStart({fx_chain:chainPayload,sample_rate:ctx.sampleRate||44100});}catch(e){console.warn('[FX RT track] start fail',trackId,path,e);return;}const entry={sessionId:st.session_id,ws:null,node:null,ready:false,path,spliced:null,chainKey:fxRtTrackChainKey(chain)+'|vb:'+(track&&track.vstFxBypass?'1':'0'),paramsBySlot:chain.map(s=>fxRtEntryParams(s,null)),inQueue:[],pumpTimer:null,lastInSent:0,flushing:false,flushTimer:null};fxRtTracks[key]=entry;fxRtGuiPushShm();try{await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202609062020`);const node=new AudioWorkletNode(ctx,'sf-fx-realtime',{numberOfInputs:1,numberOfOutputs:1,outputChannelCount:[2]});entry.node=node;const u=new URL(API_BASE_URL);const wsProto=u.protocol==='https:'?'wss://':'ws://';// WS to 'localhost' bi tre ~300ms (Chromium thu ::1 truoc roi fallback) - dung 127.0.0.1
 const wsHost=u.hostname==='localhost'||u.hostname==='::1'?'127.0.0.1'+(u.port?':'+u.port:''):u.host;const tok=localStorage.getItem('sonic_token')||'';const ws=new WebSocket(`${wsProto}${wsHost}${st.ws_url}${tok?'?token='+encodeURIComponent(tok):''}`);entry.ws=ws;ws.binaryType='arraybuffer';ws.onopen=()=>{entry.ready=true;entry.inQueue=[];// bỏ audio stale trước khi WS open — hết lag khởi đầu
 fxRtTrackSplice(trackId,path);try{(entry.paramsBySlot||[]).forEach((pl,slot)=>pl.forEach(p=>ws.send(JSON.stringify({cmd:'set_param',slot,key:p.key,value:p.value}))));}catch(e){}};ws.onmessage=ev=>{if(typeof ev.data==='string'){try{const d=JSON.parse(ev.data);if(d&&d.cmd==='flush_done'){entry.flushing=false;if(entry.flushTimer){clearTimeout(entry.flushTimer);entry.flushTimer=null;}if(entry.node)entry.node.port.postMessage({type:'flush_done'});}}catch(e){}return;}if(!(ev.data instanceof ArrayBuffer)||!entry.node)return;if(entry.flushing)return;// V24: output stale trong luc flush — drop
 const f=new Float32Array(ev.data);const half=f.length/2;const l=new Float32Array(half);const r=new Float32Array(half);for(let i=0;i<half;i++){l[i]=f[i*2];r[i]=f[i*2+1];}entry.node.port.postMessage({type:'out',l,r});};ws.onclose=()=>fxRtTrackStop(trackId,path,true);ws.onerror=()=>{try{ws.close();}catch(e){}};entry.node.port.onmessage=ev=>{const d=ev.data;if(!d||!entry.ws)return;if(d.type==='flush'){// V24: nhu master — worklet underrun-resume → flush engine ring
 // (xoa backlog stale) → het lag ~1s sau stall. Fallback phong ack mat.
 if(entry.ws&&entry.ws.readyState===1){try{entry.ws.send(JSON.stringify({cmd:'flush'}));}catch(e){}}entry.flushing=true;if(entry.flushTimer)clearTimeout(entry.flushTimer);entry.flushTimer=setTimeout(()=>{entry.flushTimer=null;entry.flushing=false;if(entry.node)entry.node.port.postMessage({type:'flush_done'});},500);return;}if(d.type==='set_param'){try{entry.ws.send(JSON.stringify({cmd:'set_param',slot:d.slot,key:d.key,value:d.value}));}catch(e){}return;}if(d.type!=='in')return;// Burst 4 block (1024 mẫu) → tách 4 WS frame 512 floats → bridge batch 4.
-// Pace 1 burst/21ms (giống master) — tránh dồn frame sau stall làm tràn ring.
-entry.inQueue.push(d);const pump=()=>{if(!entry.inQueue.length)return;const now=Date.now();while(entry.inQueue.length&&now-entry.lastInSent>=FXRT_BURST_MS){entry.lastInSent=now;const dd=entry.inQueue.shift();if(entry.ws&&entry.ws.readyState===1){try{const f=new Float32Array(dd.data);if(f.length>512){for(let i=0;i<f.length;i+=512)entry.ws.send(f.slice(i,i+512).buffer);}else{entry.ws.send(dd.data);}}catch(e){}}}if(entry.inQueue.length){if(entry.pumpTimer)clearTimeout(entry.pumpTimer);entry.pumpTimer=setTimeout(pump,Math.max(1,FXRT_BURST_MS-(now-entry.lastInSent)));}else if(entry.pumpTimer){clearTimeout(entry.pumpTimer);entry.pumpTimer=null;}};pump();};}catch(e){console.warn('[FX RT track] setup fail',trackId,path,e);fxRtTrackStop(trackId,path,true);}};const fxRtTrackUnsplice=(trackId,path)=>{const entry=fxRtTracks[trackId+':'+path];if(!entry||!entry.spliced||!entry.node)return;try{entry.node.disconnect();try{entry.spliced.tail.connect(entry.spliced.dest);}catch(e){}entry.spliced=null;}catch(e){console.warn('[FX RT track] unsplice fail',trackId,path,e);}};// Chain đổi trên session ĐANG CHẠY — set_chain KHÔNG restart (bridge swap
+// Gửi NGAY (không pace setTimeout) như master path (proven): worklet đã
+// pace 1 burst/21.33ms theo đồng hồ audio; timer main-thread bận/trễ →
+// input gửi trễ → engine chỉ sản xuất khi có input → cushion cạn →
+// crackle. Burst sau stall: engine hấp thụ (in ring 4 slot, drop-oldest).
+if(entry.ws&&entry.ws.readyState===1){try{const f=new Float32Array(d.data);if(f.length>512){for(let i=0;i<f.length;i+=512)entry.ws.send(f.slice(i,i+512).buffer);}else{entry.ws.send(d.data);}}catch(e){}}};}catch(e){console.warn('[FX RT track] setup fail',trackId,path,e);fxRtTrackStop(trackId,path,true);}};const fxRtTrackUnsplice=(trackId,path)=>{const entry=fxRtTracks[trackId+':'+path];if(!entry||!entry.spliced||!entry.node)return;try{entry.node.disconnect();try{entry.spliced.tail.connect(entry.spliced.dest);}catch(e){}entry.spliced=null;}catch(e){console.warn('[FX RT track] unsplice fail',trackId,path,e);}};// Chain đổi trên session ĐANG CHẠY — set_chain KHÔNG restart (bridge swap
 // atomic khi worker load xong) → load VST FX / đổi preset GUI không ngắt
 // âm/crackle. entry.chainKey cập nhật ngay — reconcile sau đó thấy khớp.
 const fxRtTrackSetChain=(trackId,path,track,chainKey)=>{const key=trackId+':'+path;const entry=fxRtTracks[key];if(!entry||!entry.ws||entry.ws.readyState!==1)return;const chain=fxRtTrackChain(track);if(!chain.length)return;const chainPayload=chain.map(s=>s.type==='vst3'?{type:'vst3',path:s.path,name:s.name||s.path,preset_b64:s.preset_b64||'',bypass:!!s.bypass||!!(track&&track.vstFxBypass)}:{type:'builtin',id:s.type,params:s.params&&Object.keys(s.params).length?s.params:{},bypass:!!s.bypass});entry.chainKey=chainKey;window.SonicAPI.fxRealtimeSetChain({session_id:entry.sessionId,fx_chain:chainPayload}).then(()=>{try{(entry.paramsBySlot||[]).forEach((pl,slot)=>pl.forEach(p=>{if(entry.ws&&entry.ws.readyState===1)entry.ws.send(JSON.stringify({cmd:'set_param',slot,key:p.key,value:p.value}));}));}catch(e){}}).catch(e=>console.warn('[FX RT track] set-chain fail',trackId,path,e));};const fxRtTrackSplice=(trackId,path)=>{const key=trackId+':'+path;const entry=fxRtTracks[key];const node=activeTrackNodesRef.current[trackId];if(!entry||!entry.ready||!entry.node||!node||entry.spliced)return;const tail=path==='audio'?node.fxEntry:node.sfEntry;const dest=path==='audio'?node.fxLegacyIn:node.sfOut;if(!tail||!dest)return;try{tail.disconnect(dest);entry.node.connect(dest);tail.connect(entry.node);entry.spliced={tail,dest};console.log('[FX RT track] spliced',trackId,path);}catch(e){console.warn('[FX RT track] splice fail',trackId,path,e);}};const fxRtTrackStop=(trackId,path,silent)=>{const key=trackId+':'+path;const entry=fxRtTracks[key];if(!entry)return;if(entry.pumpTimer){clearInterval(entry.pumpTimer);entry.pumpTimer=null;}if(entry.flushTimer){clearTimeout(entry.flushTimer);entry.flushTimer=null;}entry.inQueue=[];entry.flushing=false;try{fxRtTrackUnsplice(trackId,path);if(entry.node){entry.node.port.onmessage=null;try{entry.node.disconnect();}catch(e){}entry.node=null;}}catch(e){}try{if(entry.ws){entry.ws.onclose=null;entry.ws.onmessage=null;try{entry.ws.close();}catch(e){}entry.ws=null;}}catch(e){}const sid=entry.sessionId;delete fxRtTracks[key];fxRtGuiPushShm();if(sid){try{window.SonicAPI.fxRealtimeStop({session_id:sid}).catch(()=>{});}catch(e){}}};const fxRtTrackReconcile=(trackId,node,track)=>{try{const chain=fxRtTrackChain(track);const chainKey=fxRtTrackChainKey(chain)+'|vb:'+(track&&track.vstFxBypass?'1':'0');const wantPaths=chain.length?fxRtTrackPaths(track):[];const prefix=trackId+':';Object.keys(fxRtTracks).forEach(k=>{if(!k.startsWith(prefix))return;const p=k.slice(prefix.length);if(wantPaths.indexOf(p)<0)fxRtTrackStop(trackId,p,true);});if(!isPlayingRef.current)return;wantPaths.forEach(p=>{const key=trackId+':'+p;const entry=fxRtTracks[key];if(!entry)fxRtTrackStart(trackId,track,p);else if(entry.chainKey!==chainKey){// Chain đổi (load/đổi VST FX, preset GUI, bypass slot) — session

app/static/js/sf-fx-realtime.js

@@ -32,7 +32,7 @@ class SfFxRealtimeProcessor extends AudioWorkletProcessor {
     this.FILL = 24;             // V44: 24 block ~128ms @48k: buffer khởi đầu — hấp thụ jitter main-thread + stall deschedule bridge 68-138ms. PDC 7936 = (7+24)*256 (fxRtApplyPdc). V43 16 -> cushion ~9 (q 3-9) chua du: stall 68-82ms van gay underrun. V44 len 24 -> cushion ~17 (~90ms).
     this.RESUME_FILL = 24;     // V26: re-buffer khi resume SAU STOP (flush_for_stop) — 16 block ~85ms (V43: = FILL) → play kế tiếp bắt đầu nhanh; underrun-stall vẫn dùng FILL (crackle/wobble).
     this.resumeFill = this.FILL; // mức re-buffer khi resume sau flush — stop: RESUME_FILL, underrun-stall: FILL
-    this.CAP = 32;             // V40: cap queue chặn overflow (~170ms)
+    this.CAP = 48;             // V47: 32->48 (~256ms) — hết click cap-drop sau stall (cap=13/session cũ); KHÔNG đổi latency khởi đầu/PDC (FILL giữ 24)
     this.HOLD_FADE = 4;        // 4 block ~21ms: fade 1→0 sau HOLD hết (hết click cắt cứng)
     this.holdFadeLeft = 0;     // mẫu còn lại của fade-out khi underrun
     this.silenced = false;     // đã fade về 0 → im lặng; resume phải fade-in, không hold lại

app/templates/index.html

@@ -51,7 +51,7 @@
     <script src="/static/js/services/promptTemplateManager.js?v=202608290945"></script>
     <script src="/static/js/services/undoRedoEngine.js?v=202608290945"></script>
     <script src="/static/js/services/chordTheory.js?v=202608290945"></script>
-    <script src="/static/js/app.precompiled.js?v=202609061838" defer></script>
+    <script src="/static/js/app.precompiled.js?v=202609062020" defer></script>
     <link rel="stylesheet" href="/static/css/styles.css?v=202608290945">
     <style>
         :root {

native_bridge/juce_fx/CMakeLists.txt

@@ -39,8 +39,8 @@ target_compile_definitions(juce_fx_bridge PRIVATE JUCE_PLUGINHOST_VST3=1)
 # M2 GUI thread: runDispatchLoopUntil cần modal loops được phép
 target_compile_definitions(juce_fx_bridge PRIVATE JUCE_MODAL_LOOPS_PERMITTED=1)
 if(WIN32)
-  # timeBeginPeriod (winmm) — như fx_vst_bridge
-  target_link_libraries(juce_fx_bridge PRIVATE winmm)
+  # timeBeginPeriod (winmm) + MMCSS AvSetMmThreadCharacteristics (avrt)
+  target_link_libraries(juce_fx_bridge PRIVATE winmm avrt)
 endif()
 
 # ── M1 selftest (editor API — KHÔNG ship): verify editor host trên instance

native_bridge/juce_fx/JuceFxEngine.cpp

@@ -378,6 +378,19 @@ bool JuceFxEngine::isEditorOpen(uint32_t slot) const {
     return impl_->editors[slot].open;
 }
 
+bool JuceFxEngine::guiBusy() const {
+    {
+        std::lock_guard<std::mutex> lk(impl_->queueMutex);
+        if (!impl_->editorQueue.empty()) return true;
+    }
+    {
+        std::lock_guard<std::mutex> lk(impl_->editorMutex);
+        for (const auto& se : impl_->editors)
+            if (se.open) return true;
+    }
+    return !impl_->retryOpens.empty();  // GUI-thread-only — chỉ GUI thread gọi
+}
+
 std::string JuceFxEngine::takeCapturedState(uint32_t slot) {
     std::lock_guard<std::mutex> lk(impl_->editorMutex);
     if (slot >= impl_->editors.size()) return {};

native_bridge/juce_fx/JuceFxEngine.h

@@ -78,6 +78,10 @@ public:
     // Thread-safe đọc: editor slot đang hiển thị (Show/Hide) không.
     bool isEditorVisible(uint32_t slot) const;
 
+    // GUI host: có việc editor cần tick nhanh không (queue lệnh chờ / editor
+    // đang mở / retry Open chờ). Gọi từ GUI thread (retryOpens GUI-thread-only).
+    bool guiBusy() const;
+
     void shutdown();
 
 private:

native_bridge/juce_fx/JuceFxGuiHost.cpp

@@ -568,13 +568,14 @@ void JuceFxGuiHost::guiMain() {
     // Thread này trở thành JUCE message thread.
     std::cerr << "[JuceFxGuiHost] guiMain start" << std::endl;
     juce::initialiseJuce_GUI();
-    std::cerr << "[JuceFxGuiHost] initialiseJuce_GUI ok" << std::endl;
+    std::cerr << "[JuceFxGuiHost] initialiseJuce_GUI ok" << std::endl;
     // Cadence inline (30ms busy / 200ms idle) — KHÔNG dùng juce::Timer: trên GUI thread riêng,
     // timer callback không bao giờ fire dù runDispatchLoopUntil pump liên tục
     // (test cho thấy 0 tick). tick() ở đây chạy trên chính message thread nên
     // pump + tạo/xoá Component an toàn.
     {
-        using clock = std::chrono::steady_clock;
+        using clock = std::chrono::steady_clock;
+        const auto fastMs = std::chrono::milliseconds(30);
         const auto slowMs = std::chrono::milliseconds(200);
         auto lastTick = clock::now();
         while (!quit_.load()) {
@@ -596,7 +597,11 @@ void JuceFxGuiHost::guiMain() {
                 impl_->guiCv.notify_all();
             }
             juce::MessageManager::getInstance()->runDispatchLoopUntil(10);
-            const auto now = clock::now();
+            const auto now = clock::now();
+            // Cadence động: có việc editor (queue/open/retry) → 30ms giữ
+            // anchor/reconcile phản hồi nhanh; idle (không editor) → 200ms —
+            // giảm wakeup + churn GUI thread BELOW_NORMAL khi chỉ chạy audio.
+            const auto curMs = engine_.guiBusy() ? fastMs : slowMs;
             if (now - lastTick >= curMs) {
                 tick();
                 lastTick = now;

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;