commit 286b3a8b2d071ee2652232b923770757f0647468
author Josh Gao <jmgao@google.com> Tue Oct 24 14:00:09 2017 -0700
committer Josh Gao <jmgao@google.com> Tue Oct 24 14:02:54 2017 -0700
tree e10a2b83141f4ce4af53fd8e4318103ad884c714
parent d330bbbac846d0dfbc797ca594bc69f3442494d1

Fix pthread benchmarks.

PauseTiming and ResumeTiming are thread-local, and unbalanced calls to
them leads to obviously bogus results like:

    Benchmark                          Time            CPU Iterations
    -----------------------------------------------------------------
    BM_pthread_exit_and_join      212600 ns    59981418 ns         12
    BM_pthread_create_and_run  212997341 ns -1569132344 ns       1000

Bug: http://b/68170209
Test: ran bionic benchmarks
Change-Id: Ia88cd6af9ff524443850d834a96cf5dd9c7f3ed9

benchmarks/pthread_benchmark.cpp

diff --git a/benchmarks/pthread_benchmark.cpp b/benchmarks/pthread_benchmark.cpp
index 7a967ef..1ad6345 100644
--- a/benchmarks/pthread_benchmark.cpp
+++ b/benchmarks/pthread_benchmark.cpp
@@ -137,9 +137,7 @@
 }
 BIONIC_BENCHMARK(BM_pthread_create);
 
-static void* RunThread(void* arg) {
-  benchmark::State& state = *reinterpret_cast<benchmark::State*>(arg);
-  state.PauseTiming();
+static void* RunThread(void*) {
   return NULL;
 }
 
@@ -148,22 +146,18 @@
     pthread_t thread;
     pthread_create(&thread, NULL, RunThread, &state);
     pthread_join(thread, NULL);
-    state.ResumeTiming();
   }
 }
 BIONIC_BENCHMARK(BM_pthread_create_and_run);
 
-static void* ExitThread(void* arg) {
-  benchmark::State& state = *reinterpret_cast<benchmark::State*>(arg);
-  state.ResumeTiming();
+static void* ExitThread(void*) {
   pthread_exit(NULL);
 }
 
 static void BM_pthread_exit_and_join(benchmark::State& state) {
   while (state.KeepRunning()) {
-    state.PauseTiming();
     pthread_t thread;
-    pthread_create(&thread, NULL, ExitThread, &state);
+    pthread_create(&thread, NULL, ExitThread, nullptr);
     pthread_join(thread, NULL);
   }
 }