1 files changed, 21 insertions, 7 deletions

diff --git a/test/cpp/qps/client_async.cc b/test/cpp/qps/client_async.cc
index f270cd0987..e423ee2598 100644
--- a/test/cpp/qps/client_async.cc
+++ b/test/cpp/qps/client_async.cc
@@ -46,13 +46,14 @@
 #include <grpc++/client_context.h>
 #include <grpc++/generic/generic_stub.h>
 #include <grpc/grpc.h>
+#include <grpc/support/cpu.h>
 #include <grpc/support/histogram.h>
 #include <grpc/support/log.h>
 
+#include "src/proto/grpc/testing/services.grpc.pb.h"
 #include "test/cpp/qps/client.h"
 #include "test/cpp/qps/timer.h"
 #include "test/cpp/util/create_test_channel.h"
-#include "src/proto/grpc/testing/services.grpc.pb.h"
 
 namespace grpc {
 namespace testing {
@@ -164,14 +165,15 @@ class AsyncClient : public ClientImpl<StubType, RequestType> {
               std::function<std::unique_ptr<StubType>(std::shared_ptr<Channel>)>
                   create_stub)
       : ClientImpl<StubType, RequestType>(config, create_stub),
+        num_async_threads_(NumThreads(config)),
         channel_lock_(new std::mutex[config.client_channels()]),
         contexts_(config.client_channels()),
         max_outstanding_per_channel_(config.outstanding_rpcs_per_channel()),
         channel_count_(config.client_channels()),
-        pref_channel_inc_(config.async_client_threads()) {
-    SetupLoadTest(config, config.async_client_threads());
+        pref_channel_inc_(num_async_threads_) {
+    SetupLoadTest(config, num_async_threads_);
 
-    for (int i = 0; i < config.async_client_threads(); i++) {
+    for (int i = 0; i < num_async_threads_; i++) {
       cli_cqs_.emplace_back(new CompletionQueue);
       if (!closed_loop_) {
         rpc_deadlines_.emplace_back();
@@ -324,6 +326,9 @@ class AsyncClient : public ClientImpl<StubType, RequestType> {
     return true;
   }
 
+ protected:
+  int num_async_threads_;
+
  private:
   class boolean {  // exists only to avoid data-race on vector<bool>
    public:
@@ -338,6 +343,15 @@ class AsyncClient : public ClientImpl<StubType, RequestType> {
    private:
     bool val_;
   };
+  static int NumThreads(const ClientConfig& config) {
+    int num_threads = config.async_client_threads();
+    if (num_threads <= 0) {  // Use dynamic sizing
+      num_threads = gpr_cpu_num_cores();
+      gpr_log(GPR_INFO, "Sizing client server to %d threads", num_threads);
+    }
+    return num_threads;
+  }
+
   std::vector<std::unique_ptr<CompletionQueue>> cli_cqs_;
 
   std::vector<deadline_list> rpc_deadlines_;  // per thread deadlines
@@ -363,7 +377,7 @@ class AsyncUnaryClient GRPC_FINAL
  public:
   explicit AsyncUnaryClient(const ClientConfig& config)
       : AsyncClient(config, SetupCtx, BenchmarkStubCreator) {
-    StartThreads(config.async_client_threads());
+    StartThreads(num_async_threads_);
   }
   ~AsyncUnaryClient() GRPC_OVERRIDE { EndThreads(); }
 
@@ -461,7 +475,7 @@ class AsyncStreamingClient GRPC_FINAL
     // async streaming currently only supports closed loop
     GPR_ASSERT(closed_loop_);
 
-    StartThreads(config.async_client_threads());
+    StartThreads(num_async_threads_);
   }
 
   ~AsyncStreamingClient() GRPC_OVERRIDE { EndThreads(); }
@@ -566,7 +580,7 @@ class GenericAsyncStreamingClient GRPC_FINAL
     // async streaming currently only supports closed loop
     GPR_ASSERT(closed_loop_);
 
-    StartThreads(config.async_client_threads());
+    StartThreads(num_async_threads_);
   }
 
   ~GenericAsyncStreamingClient() GRPC_OVERRIDE { EndThreads(); }