Use thread local mode in routing cuda graph class

Author: hlinsen

cpp/src/routing/cuda_graph.cuh

@@ -20,7 +20,9 @@ namespace detail {
 struct cuda_graph_t {
   void start_capture(rmm::cuda_stream_view stream)
   {
-    cudaStreamBeginCapture(stream, cudaStreamCaptureModeGlobal);
+    // Use ThreadLocal mode to allow multi-threaded batch execution
+    // Global mode blocks other streams from performing operations during capture
+    cudaStreamBeginCapture(stream, cudaStreamCaptureModeThreadLocal);
     capture_started = true;
   }