3 files changed, 59 insertions, 9 deletions

diff --git a/test/cpp/qps/client.h b/test/cpp/qps/client.h
index fada4ba767..c8809cbc5b 100644
--- a/test/cpp/qps/client.h
+++ b/test/cpp/qps/client.h
@@ -129,13 +129,17 @@ class HistogramEntry GRPC_FINAL {
 
 class Client {
  public:
-  Client() : timer_(new UsageTimer), interarrival_timer_() {}
+  Client() : timer_(new UsageTimer), interarrival_timer_() {
+    gpr_event_init(&start_requests_);
+  }
   virtual ~Client() {}
 
   ClientStats Mark(bool reset) {
     Histogram latencies;
     UsageTimer::Result timer_result;
 
+    MaybeStartRequests();
+
     // avoid std::vector for old compilers that expect a copy constructor
     if (reset) {
       Histogram* to_merge = new Histogram[threads_.size()];
@@ -189,7 +193,10 @@ class Client {
     }
   }
 
-  void EndThreads() { threads_.clear(); }
+  void EndThreads() {
+    MaybeStartRequests();
+    threads_.clear();
+  }
 
   virtual void DestroyMultithreading() = 0;
   virtual bool ThreadFunc(HistogramEntry* histogram, size_t thread_idx) = 0;
@@ -265,6 +272,13 @@ class Client {
     Thread& operator=(const Thread&);
 
     void ThreadFunc() {
+      while (!gpr_event_wait(
+          &client_->start_requests_,
+          gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
+                       gpr_time_from_seconds(1, GPR_TIMESPAN)))) {
+        gpr_log(GPR_INFO, "Waiting for benchmark to start");
+      }
+
       for (;;) {
         // run the loop body
         HistogramEntry entry;
@@ -302,6 +316,16 @@ class Client {
   size_t threads_remaining_;
   std::condition_variable threads_complete_;
 
+  gpr_event start_requests_;
+  bool started_requests_;
+
+  void MaybeStartRequests() {
+    if (!started_requests_) {
+      started_requests_ = true;
+      gpr_event_set(&start_requests_, (void*)1);
+    }
+  }
+
   void CompleteThread() {
     std::lock_guard<std::mutex> g(thread_completion_mu_);
     threads_remaining_--;
@@ -359,7 +383,7 @@ class ClientImpl : public Client {
       gpr_log(GPR_INFO, "Connecting to %s", target.c_str());
       GPR_ASSERT(channel_->WaitForConnected(
           gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
-                       gpr_time_from_seconds(30, GPR_TIMESPAN))));
+                       gpr_time_from_seconds(300, GPR_TIMESPAN))));
       stub_ = create_stub(channel_);
     }
     Channel* get_channel() { return channel_.get(); }
diff --git a/test/cpp/qps/client_sync.cc b/test/cpp/qps/client_sync.cc
index 8062424a1f..0ccf4e270b 100644
--- a/test/cpp/qps/client_sync.cc
+++ b/test/cpp/qps/client_sync.cc
@@ -130,6 +130,10 @@ class SynchronousUnaryClient GRPC_FINAL : public SynchronousClient {
     grpc::Status s =
         stub->UnaryCall(&context, request_, &responses_[thread_idx]);
     entry->set_value((UsageTimer::Now() - start) * 1e9);
+    if (!s.ok()) {
+      gpr_log(GPR_ERROR, "RPC error: %d: %s", s.error_code(),
+              s.error_message().c_str());
+    }
     return s.ok();
   }
 };
diff --git a/test/cpp/qps/driver.cc b/test/cpp/qps/driver.cc
index f67f353c4d..6965495206 100644
--- a/test/cpp/qps/driver.cc
+++ b/test/cpp/qps/driver.cc
@@ -45,6 +45,7 @@
 #include <grpc/support/host_port.h>
 #include <grpc/support/log.h>
 
+#include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/support/env.h"
 #include "src/proto/grpc/testing/services.grpc.pb.h"
 #include "test/core/util/port.h"
@@ -366,12 +367,37 @@ std::unique_ptr<ScenarioResult> RunScenario(
     if (!clients[i].stream->Write(args)) {
       gpr_log(GPR_ERROR, "Could not write args to client %zu", i);
     }
+  }
+
+  for (size_t i = 0; i < num_clients; i++) {
     ClientStatus init_status;
     if (!clients[i].stream->Read(&init_status)) {
       gpr_log(GPR_ERROR, "Client %zu did not yield initial status", i);
     }
   }
 
+  // Send an initial mark: clients can use this to know that everything is ready
+  // to start
+  gpr_log(GPR_INFO, "Initiating");
+  ServerArgs server_mark;
+  server_mark.mutable_mark()->set_reset(true);
+  ClientArgs client_mark;
+  client_mark.mutable_mark()->set_reset(true);
+  ServerStatus server_status;
+  ClientStatus client_status;
+  for (size_t i = 0; i < num_clients; i++) {
+    auto client = &clients[i];
+    if (!client->stream->Write(client_mark)) {
+      gpr_log(GPR_ERROR, "Couldn't write mark to client %zu", i);
+    }
+  }
+  for (size_t i = 0; i < num_clients; i++) {
+    auto client = &clients[i];
+    if (!client->stream->Read(&client_status)) {
+      gpr_log(GPR_ERROR, "Couldn't get status from client %zu", i);
+    }
+  }
+
   // Let everything warmup
   gpr_log(GPR_INFO, "Warming up");
   gpr_timespec start = gpr_now(GPR_CLOCK_REALTIME);
@@ -380,10 +406,6 @@ std::unique_ptr<ScenarioResult> RunScenario(
 
   // Start a run
   gpr_log(GPR_INFO, "Starting");
-  ServerArgs server_mark;
-  server_mark.mutable_mark()->set_reset(true);
-  ClientArgs client_mark;
-  client_mark.mutable_mark()->set_reset(true);
   for (size_t i = 0; i < num_servers; i++) {
     auto server = &servers[i];
     if (!server->stream->Write(server_mark)) {
@@ -396,8 +418,6 @@ std::unique_ptr<ScenarioResult> RunScenario(
       gpr_log(GPR_ERROR, "Couldn't write mark to client %zu", i);
     }
   }
-  ServerStatus server_status;
-  ClientStatus client_status;
   for (size_t i = 0; i < num_servers; i++) {
     auto server = &servers[i];
     if (!server->stream->Read(&server_status)) {
@@ -419,6 +439,8 @@ std::unique_ptr<ScenarioResult> RunScenario(
       start,
       gpr_time_from_seconds(warmup_seconds + benchmark_seconds, GPR_TIMESPAN)));
 
+  gpr_timer_set_enabled(0);
+
   // Finish a run
   std::unique_ptr<ScenarioResult> result(new ScenarioResult);
   Histogram merged_latencies;