2 files changed, 11 insertions, 4 deletions
diff --git a/test/cpp/qps/client.h b/test/cpp/qps/client.h
index 5a9027a4a2..175529f01b 100644
--- a/test/cpp/qps/client.h
+++ b/test/cpp/qps/client.h
@@ -39,6 +39,7 @@
 #include <vector>
 
 #include <grpc++/support/byte_buffer.h>
+#include <grpc++/support/channel_arguments.h>
 #include <grpc++/support/slice.h>
 #include <grpc/support/log.h>
 #include <grpc/support/time.h>
@@ -280,7 +281,7 @@ class ClientImpl : public Client {
         create_stub_(create_stub) {
     for (int i = 0; i < config.client_channels(); i++) {
       channels_[i].init(config.server_targets(i % config.server_targets_size()),
-                        config, create_stub_);
+                        config, create_stub_, i);
     }
 
     ClientRequestCreator<RequestType> create_req(&request_,
@@ -303,14 +304,17 @@ class ClientImpl : public Client {
     }
     void init(const grpc::string& target, const ClientConfig& config,
               std::function<std::unique_ptr<StubType>(std::shared_ptr<Channel>)>
-                  create_stub) {
+                  create_stub,
+              int shard) {
       // We have to use a 2-phase init like this with a default
       // constructor followed by an initializer function to make
       // old compilers happy with using this in std::vector
+      ChannelArguments args;
+      args.SetInt("shard_to_ensure_no_subchannel_merges", shard);
       channel_ = CreateTestChannel(
           target, config.security_params().server_host_override(),
-          config.has_security_params(),
-          !config.security_params().use_test_ca());
+          config.has_security_params(), !config.security_params().use_test_ca(),
+          std::shared_ptr<CallCredentials>(), args);
       stub_ = create_stub(channel_);
     }
     Channel* get_channel() { return channel_.get(); }
diff --git a/test/cpp/qps/driver.cc b/test/cpp/qps/driver.cc
index 2583ceb819..04b2b453f9 100644
--- a/test/cpp/qps/driver.cc
+++ b/test/cpp/qps/driver.cc
@@ -83,6 +83,7 @@ static std::unordered_map<string, std::deque<int>> get_hosts_and_cores(
       auto stub = WorkerService::NewStub(
           CreateChannel(*it, InsecureChannelCredentials()));
       grpc::ClientContext ctx;
+      ctx.set_fail_fast(false);
       CoreRequest dummy;
       CoreResponse cores;
       grpc::Status s = stub->CoreCount(&ctx, dummy, &cores);
@@ -166,6 +167,7 @@ namespace runsc {
 static ClientContext* AllocContext(list<ClientContext>* contexts) {
   contexts->emplace_back();
   auto context = &contexts->back();
+  context->set_fail_fast(false);
   return context;
 }
 
@@ -435,6 +437,7 @@ void RunQuit() {
         CreateChannel(workers[i], InsecureChannelCredentials()));
     Void dummy;
     grpc::ClientContext ctx;
+    ctx.set_fail_fast(false);
     GPR_ASSERT(stub->QuitWorker(&ctx, dummy, &dummy).ok());
   }
 }