Merge pull request #10348 from sreecha/init-free-cq

Do not call grpc_init() for per-call-completion-queues created by a C++ sync server

include/grpc++/impl/codegen/grpc_library.h

@@ -51,18 +51,26 @@ extern GrpcLibraryInterface* g_glip;
 /// Classes that require gRPC to be initialized should inherit from this class.
 class GrpcLibraryCodegen {
  public:
-  GrpcLibraryCodegen() {
-    GPR_CODEGEN_ASSERT(g_glip &&
-                       "gRPC library not initialized. See "
-                       "grpc::internal::GrpcLibraryInitializer.");
-    g_glip->init();
+  GrpcLibraryCodegen(bool call_grpc_init = true) : grpc_init_called_(false) {
+    if (call_grpc_init) {
+      GPR_CODEGEN_ASSERT(g_glip &&
+                         "gRPC library not initialized. See "
+                         "grpc::internal::GrpcLibraryInitializer.");
+      g_glip->init();
+      grpc_init_called_ = true;
+    }
   }
   virtual ~GrpcLibraryCodegen() {
-    GPR_CODEGEN_ASSERT(g_glip &&
-                       "gRPC library not initialized. See "
-                       "grpc::internal::GrpcLibraryInitializer.");
-    g_glip->shutdown();
+    if (grpc_init_called_) {
+      GPR_CODEGEN_ASSERT(g_glip &&
+                         "gRPC library not initialized. See "
+                         "grpc::internal::GrpcLibraryInitializer.");
+      g_glip->shutdown();
+    }
   }
+
+ private:
+  bool grpc_init_called_;
 };
 
 }  // namespace grpc

src/cpp/common/completion_queue_cc.cc

@@ -43,7 +43,12 @@ namespace grpc {
 
 static internal::GrpcLibraryInitializer g_gli_initializer;
 
-CompletionQueue::CompletionQueue(grpc_completion_queue* take) : cq_(take) {
+// 'CompletionQueue' constructor can safely call GrpcLibraryCodegen(false) here
+// i.e not have GrpcLibraryCodegen call grpc_init(). This is because, to create
+// a 'grpc_completion_queue' instance (which is being passed as the input to
+// this constructor), one must have already called grpc_init().
+CompletionQueue::CompletionQueue(grpc_completion_queue* take)
+    : GrpcLibraryCodegen(false), cq_(take) {
   InitialAvalanching();
 }
 

test/cpp/microbenchmarks/bm_cq.cc

@@ -58,6 +58,17 @@ static void BM_CreateDestroyCpp(benchmark::State& state) {
 }
 BENCHMARK(BM_CreateDestroyCpp);
 
+/* Create cq using a different constructor */
+static void BM_CreateDestroyCpp2(benchmark::State& state) {
+  TrackCounters track_counters;
+  while (state.KeepRunning()) {
+    grpc_completion_queue* core_cq = grpc_completion_queue_create(NULL);
+    CompletionQueue cq(core_cq);
+  }
+  track_counters.Finish(state);
+}
+BENCHMARK(BM_CreateDestroyCpp2);
+
 static void BM_CreateDestroyCore(benchmark::State& state) {
   TrackCounters track_counters;
   while (state.KeepRunning()) {