use timeouts with proper fixture multipliers rather than raw,
since tsan slows things down a lot and may complicate issues such
as shutdown.
diff --git a/test/cpp/qps/driver.cc b/test/cpp/qps/driver.cc
index 80f6ada..e721966 100644
--- a/test/cpp/qps/driver.cc
+++ b/test/cpp/qps/driver.cc
@@ -196,10 +196,7 @@
   // Trim to just what we need
   workers.resize(num_clients + num_servers);
 
-  gpr_timespec deadline =
-      gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
-                   gpr_time_from_seconds(
-                       warmup_seconds + benchmark_seconds + 20, GPR_TIMESPAN));
+  gpr_timespec deadline = GRPC_TIMEOUT_SECONDS_TO_DEADLINE(20);
 
   // Start servers
   using runsc::ServerData;
diff --git a/test/cpp/qps/server_async.cc b/test/cpp/qps/server_async.cc
index 1302d71..2024e0b 100644
--- a/test/cpp/qps/server_async.cc
+++ b/test/cpp/qps/server_async.cc
@@ -51,6 +51,7 @@
 #include <gtest/gtest.h>
 
 #include "src/proto/grpc/testing/services.grpc.pb.h"
+#include "test/core/util/test_config.h"
 #include "test/cpp/qps/server.h"
 
 namespace grpc {
@@ -129,7 +130,7 @@
     }
   }
   ~AsyncQpsServerTest() {
-    auto deadline = std::chrono::system_clock::now() + std::chrono::seconds(10);
+    auto deadline = GRPC_TIMEOUT_SECONDS_TO_DEADLINE(10);
     server_->Shutdown(deadline);
     for (auto ss = shutdown_state_.begin(); ss != shutdown_state_.end(); ++ss) {
       (*ss)->set_shutdown();