2 files changed, 37 insertions, 23 deletions

diff --git a/test/cpp/qps/client_sync.cc b/test/cpp/qps/client_sync.cc
index 0809eb5b6c..264293561d 100644
--- a/test/cpp/qps/client_sync.cc
+++ b/test/cpp/qps/client_sync.cc
@@ -66,11 +66,11 @@ class SynchronousClient : public Client {
  public:
   SynchronousClient(const ClientConfig& config) : Client(config) {
     num_threads_ =
-      config.outstanding_rpcs_per_channel() * config.client_channels();
+        config.outstanding_rpcs_per_channel() * config.client_channels();
     responses_.resize(num_threads_);
   }
 
-  virtual ~SynchronousClient() {};
+  virtual ~SynchronousClient(){};
 
  protected:
   size_t num_threads_;
@@ -79,10 +79,12 @@ class SynchronousClient : public Client {
 
 class SynchronousUnaryClient GRPC_FINAL : public SynchronousClient {
  public:
-  SynchronousUnaryClient(const ClientConfig& config):
-    SynchronousClient(config) {StartThreads(num_threads_);}
-  ~SynchronousUnaryClient() {EndThreads();}
-  
+  SynchronousUnaryClient(const ClientConfig& config)
+      : SynchronousClient(config) {
+    StartThreads(num_threads_);
+  }
+  ~SynchronousUnaryClient() { EndThreads(); }
+
   bool ThreadFunc(Histogram* histogram, size_t thread_idx) GRPC_OVERRIDE {
     auto* stub = channels_[thread_idx % channels_.size()].get_stub();
     double start = Timer::Now();
@@ -96,43 +98,46 @@ class SynchronousUnaryClient GRPC_FINAL : public SynchronousClient {
 
 class SynchronousStreamingClient GRPC_FINAL : public SynchronousClient {
  public:
-  SynchronousStreamingClient(const ClientConfig& config):
-    SynchronousClient(config) {
-    for (size_t thread_idx=0;thread_idx<num_threads_;thread_idx++){
+  SynchronousStreamingClient(const ClientConfig& config)
+    : SynchronousClient(config), context_(num_threads_), stream_(num_threads_) {
+    for (size_t thread_idx = 0; thread_idx < num_threads_; thread_idx++) {
       auto* stub = channels_[thread_idx % channels_.size()].get_stub();
-      stream_ = stub->StreamingCall(&context_);
+      stream_[thread_idx] = stub->StreamingCall(&context_[thread_idx]);
     }
     StartThreads(num_threads_);
   }
   ~SynchronousStreamingClient() {
     EndThreads();
-    if (stream_) {
-      SimpleResponse response;
-      stream_->WritesDone();
-      EXPECT_TRUE(stream_->Finish().IsOk());
+    for (auto stream = stream_.begin(); stream != stream_.end(); stream++) {
+      if (*stream) {
+	(*stream)->WritesDone();
+	EXPECT_TRUE((*stream)->Finish().IsOk());
+      }
     }
   }
 
   bool ThreadFunc(Histogram* histogram, size_t thread_idx) GRPC_OVERRIDE {
     double start = Timer::Now();
-    if (stream_->Write(request_) && stream_->Read(&responses_[thread_idx])) {
+    if (stream_[thread_idx]->Write(request_) &&
+	stream_[thread_idx]->Read(&responses_[thread_idx])) {
       histogram->Add((Timer::Now() - start) * 1e9);
       return true;
     }
     return false;
   }
-  private:
-    grpc::ClientContext context_;
-    std::unique_ptr<grpc::ClientReaderWriter<SimpleRequest,
-                                             SimpleResponse>> stream_;
+
+ private:
+  std::vector<grpc::ClientContext> context_;
+  std::vector<std::unique_ptr<grpc::ClientReaderWriter<
+				SimpleRequest, SimpleResponse>>> stream_;
 };
 
-std::unique_ptr<Client>
-CreateSynchronousUnaryClient(const ClientConfig& config) {
+std::unique_ptr<Client> CreateSynchronousUnaryClient(
+    const ClientConfig& config) {
   return std::unique_ptr<Client>(new SynchronousUnaryClient(config));
 }
-std::unique_ptr<Client>
-CreateSynchronousStreamingClient(const ClientConfig& config) {
+std::unique_ptr<Client> CreateSynchronousStreamingClient(
+    const ClientConfig& config) {
   return std::unique_ptr<Client>(new SynchronousStreamingClient(config));
 }
 
diff --git a/test/cpp/qps/qps_driver.cc b/test/cpp/qps/qps_driver.cc
index 93b1247d73..fc8e04201c 100644
--- a/test/cpp/qps/qps_driver.cc
+++ b/test/cpp/qps/qps_driver.cc
@@ -94,6 +94,15 @@ int main(int argc, char** argv) {
   server_config.set_threads(FLAGS_server_threads);
   server_config.set_enable_ssl(FLAGS_enable_ssl);
 
+  // If we're running a sync-server streaming test, make sure
+  // that we have at least as many threads as the active streams
+  // or else threads will be blocked from forward progress and the
+  // client will deadlock on a timer.
+  GPR_ASSERT(!(server_type == grpc::testing::SYNCHRONOUS_SERVER &&
+               rpc_type == grpc::testing::STREAMING &&
+               FLAGS_server_threads <  FLAGS_client_channels *
+               FLAGS_outstanding_rpcs_per_channel));
+
   auto result = RunScenario(client_config, FLAGS_num_clients,
                             server_config, FLAGS_num_servers,
                             FLAGS_warmup_seconds, FLAGS_benchmark_seconds,