From 25b037fe9d72bb1d0ef045381e7aaec944fba2e6 Mon Sep 17 00:00:00 2001
From: Craig Tiller <ctiller@google.com>
Date: Wed, 18 Oct 2017 14:03:08 -0700
Subject: [PATCH] Fix benchmark crash

---
 .../fullstack_streaming_ping_pong.h           | 47 +++++++++++--------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/test/cpp/microbenchmarks/fullstack_streaming_ping_pong.h b/test/cpp/microbenchmarks/fullstack_streaming_ping_pong.h
index 6df044f3440..06d18b890d8 100644
--- a/test/cpp/microbenchmarks/fullstack_streaming_ping_pong.h
+++ b/test/cpp/microbenchmarks/fullstack_streaming_ping_pong.h
@@ -278,7 +278,7 @@ static void BM_StreamingPingPongWithCoalescingApi(benchmark::State& state) {
 
       void* t;
       bool ok;
-      int need_tags;
+      int expect_tags;
 
       // Send 'max_ping_pongs' number of ping pong messages
       int ping_pong_cnt = 0;
@@ -289,7 +289,7 @@ static void BM_StreamingPingPongWithCoalescingApi(benchmark::State& state) {
           request_rw->Write(send_request, tag(2));  // Start client send
         }
 
-        need_tags = (1 << 2) | (1 << 3) | (1 << 4) | (1 << 5);
+        int await_tags = (1 << 2);
 
         if (ping_pong_cnt == 0) {
           // wait for the server call structure (call_hook, etc.) to be
@@ -301,8 +301,8 @@ static void BM_StreamingPingPongWithCoalescingApi(benchmark::State& state) {
             // In some cases tag:2 comes before tag:0 (write tag comes out
             // first), this while loop is to make sure get tag:0.
             int i = (int)(intptr_t)t;
-            GPR_ASSERT(need_tags & (1 << i));
-            need_tags &= ~(1 << i);
+            GPR_ASSERT(await_tags & (1 << i));
+            await_tags &= ~(1 << i);
             GPR_ASSERT(fixture->cq()->Next(&t, &ok));
           }
         }
@@ -310,7 +310,11 @@ static void BM_StreamingPingPongWithCoalescingApi(benchmark::State& state) {
         response_rw.Read(&recv_request, tag(3));   // Start server recv
         request_rw->Read(&recv_response, tag(4));  // Start client recv
 
-        while (need_tags) {
+        await_tags |= (1 << 3) | (1 << 4);
+        expect_tags = await_tags;
+        await_tags |= (1 << 5);
+
+        while (await_tags != 0) {
           GPR_ASSERT(fixture->cq()->Next(&t, &ok));
           GPR_ASSERT(ok);
           int i = (int)(intptr_t)t;
@@ -321,34 +325,39 @@ static void BM_StreamingPingPongWithCoalescingApi(benchmark::State& state) {
               if (write_and_finish == 1) {
                 response_rw.WriteAndFinish(send_response, WriteOptions(),
                                            Status::OK, tag(5));
+                expect_tags |= (1 << 5);
               } else {
                 response_rw.WriteLast(send_response, WriteOptions(), tag(5));
-                // WriteLast buffers the write, so neither server write op nor
-                // client read op will finish inside the while loop.
-                need_tags &= ~(1 << 4);
-                need_tags &= ~(1 << 5);
+                // WriteLast buffers the write, so it's possible neither server
+                // write op nor client read op will finish inside the while
+                // loop.
+                await_tags &= ~(1 << 4);
+                await_tags &= ~(1 << 5);
+                expect_tags |= (1 << 5);
               }
             } else {
               response_rw.Write(send_response, tag(5));
+              expect_tags |= (1 << 5);
             }
           }
 
-          GPR_ASSERT(need_tags & (1 << i));
-          need_tags &= ~(1 << i);
+          GPR_ASSERT(expect_tags & (1 << i));
+          expect_tags &= ~(1 << i);
+          await_tags &= ~(1 << i);
         }
 
         ping_pong_cnt++;
       }
 
       if (max_ping_pongs == 0) {
-        need_tags = (1 << 6) | (1 << 7) | (1 << 8);
+        expect_tags |= (1 << 6) | (1 << 7) | (1 << 8);
       } else {
         if (write_and_finish == 1) {
-          need_tags = (1 << 8);
+          expect_tags |= (1 << 8);
         } else {
           // server's buffered write and the client's read of the buffered write
           // tags should come up.
-          need_tags = (1 << 4) | (1 << 5) | (1 << 7) | (1 << 8);
+          expect_tags |= (1 << 7) | (1 << 8);
         }
       }
 
@@ -360,8 +369,8 @@ static void BM_StreamingPingPongWithCoalescingApi(benchmark::State& state) {
         GPR_ASSERT(fixture->cq()->Next(&t, &ok));
         while ((int)(intptr_t)t != 0) {
           int i = (int)(intptr_t)t;
-          GPR_ASSERT(need_tags & (1 << i));
-          need_tags &= ~(1 << i);
+          GPR_ASSERT(expect_tags & (1 << i));
+          expect_tags &= ~(1 << i);
           GPR_ASSERT(fixture->cq()->Next(&t, &ok));
         }
         response_rw.Finish(Status::OK, tag(7));
@@ -374,11 +383,11 @@ static void BM_StreamingPingPongWithCoalescingApi(benchmark::State& state) {
       Status recv_status;
       request_rw->Finish(&recv_status, tag(8));
 
-      while (need_tags) {
+      while (expect_tags) {
         GPR_ASSERT(fixture->cq()->Next(&t, &ok));
         int i = (int)(intptr_t)t;
-        GPR_ASSERT(need_tags & (1 << i));
-        need_tags &= ~(1 << i);
+        GPR_ASSERT(expect_tags & (1 << i));
+        expect_tags &= ~(1 << i);
       }
 
       GPR_ASSERT(recv_status.ok());