[d3d11] Determine pending commands based on sequence number

We get this for free and this allows us to query how many CS chunks
have been emitted since the last flush.

src/d3d11/d3d11_context_imm.cpp

@@ -170,7 +170,7 @@ namespace dxvk {
     
     D3D10DeviceLock lock = LockContext();
     
-    if (m_csIsBusy || !m_csChunk->empty()) {
+    if (GetPendingCsChunks()) {
       // Add commands to flush the threaded
       // context, then flush the command list
       EmitCs([] (DxvkContext* ctx) {
@@ -181,7 +181,7 @@ namespace dxvk {
       
       // Reset flush timer used for implicit flushes
       m_lastFlush = dxvk::high_resolution_clock::now();
-      m_csIsBusy  = false;
+      m_flushSeqNum = m_csSeqNum;
     }
   }
   
@@ -257,10 +257,6 @@ namespace dxvk {
       RestoreCommandListState();
     else
       ResetContextState();
-    
-    // Mark CS thread as busy so that subsequent
-    // flush operations get executed correctly.
-    m_csIsBusy = true;
   }
   
   
@@ -833,7 +829,6 @@ namespace dxvk {
   
   void D3D11ImmediateContext::EmitCsChunk(DxvkCsChunkRef&& chunk) {
     m_csSeqNum = m_csThread.dispatchChunk(std::move(chunk));
-    m_csIsBusy = true;
   }
 
 
@@ -864,6 +859,11 @@ namespace dxvk {
   }
 
 
+  uint64_t D3D11ImmediateContext::GetPendingCsChunks() {
+    return GetCurrentSequenceNumber() - m_flushSeqNum;
+  }
+
+
   void D3D11ImmediateContext::FlushImplicit(BOOL StrongHint) {
     // Flush only if the GPU is about to go idle, in
     // order to keep the number of submissions low.

src/d3d11/d3d11_context_imm.h

@@ -88,7 +88,6 @@ namespace dxvk {
     
     DxvkCsThread            m_csThread;
     uint64_t                m_csSeqNum = 0ull;
-    bool                    m_csIsBusy = false;
 
     Rc<sync::CallbackFence> m_eventSignal;
     uint64_t                m_eventCount = 0ull;
@@ -96,6 +95,9 @@ namespace dxvk {
 
     VkDeviceSize            m_maxImplicitDiscardSize = 0ull;
 
+    uint64_t                m_flushSeqNum = 0ull;
+
+
     dxvk::high_resolution_clock::time_point m_lastFlush
       = dxvk::high_resolution_clock::now();
     
@@ -158,6 +160,8 @@ namespace dxvk {
 
     uint64_t GetCurrentSequenceNumber();
 
+    uint64_t GetPendingCsChunks();
+
     void FlushImplicit(BOOL StrongHint);
 
     void SignalEvent(HANDLE hEvent);