Include benchmark for std::atomic

Reviewed By: yfeldblum

Differential Revision: D18926899

fbshipit-source-id: d16c1b5b54a75fe70514f25b648de70ae66b6415

folly/experimental/test/RefCountBenchmark.cpp

@@ -61,6 +61,22 @@ BENCHMARK(TLRefCountFourThreads, n) {
   benchmark<TLRefCount, 4>(n);
 }
 
+BENCHMARK(TLRefCountTwentyFourThreads, n) {
+  benchmark<TLRefCount, 24>(n);
+}
+
+BENCHMARK(AtomicOneThread, n) {
+  benchmark<std::atomic<size_t>, 1>(n);
+}
+
+BENCHMARK(AtomicFourThreads, n) {
+  benchmark<std::atomic<size_t>, 4>(n);
+}
+
+BENCHMARK(AtomicTwentyFourThreads, n) {
+  benchmark<std::atomic<size_t>, 24>(n);
+}
+
 } // namespace folly
 
 int main(int argc, char** argv) {