1 files changed, 145 insertions, 0 deletions
diff --git a/third-party/benchmark/test/perf_counters_gtest.cc b/third-party/benchmark/test/perf_counters_gtest.cc
new file mode 100644
index 000000000000..2a2868a71536
--- /dev/null
+++ b/third-party/benchmark/test/perf_counters_gtest.cc
@@ -0,0 +1,145 @@
+#include <thread>
+
+#include "../src/perf_counters.h"
+#include "gtest/gtest.h"
+
+#ifndef GTEST_SKIP
+struct MsgHandler {
+  void operator=(std::ostream&){}
+};
+#define GTEST_SKIP() return MsgHandler() = std::cout
+#endif
+
+using benchmark::internal::PerfCounters;
+using benchmark::internal::PerfCounterValues;
+
+namespace {
+const char kGenericPerfEvent1[] = "CYCLES";
+const char kGenericPerfEvent2[] = "BRANCHES";
+const char kGenericPerfEvent3[] = "INSTRUCTIONS";
+
+TEST(PerfCountersTest, Init) {
+  EXPECT_EQ(PerfCounters::Initialize(), PerfCounters::kSupported);
+}
+
+TEST(PerfCountersTest, OneCounter) {
+  if (!PerfCounters::kSupported) {
+    GTEST_SKIP() << "Performance counters not supported.\n";
+  }
+  EXPECT_TRUE(PerfCounters::Initialize());
+  EXPECT_TRUE(PerfCounters::Create({kGenericPerfEvent1}).IsValid());
+}
+
+TEST(PerfCountersTest, NegativeTest) {
+  if (!PerfCounters::kSupported) {
+    EXPECT_FALSE(PerfCounters::Initialize());
+    return;
+  }
+  EXPECT_TRUE(PerfCounters::Initialize());
+  EXPECT_FALSE(PerfCounters::Create({}).IsValid());
+  EXPECT_FALSE(PerfCounters::Create({""}).IsValid());
+  EXPECT_FALSE(PerfCounters::Create({"not a counter name"}).IsValid());
+  {
+    EXPECT_TRUE(PerfCounters::Create({kGenericPerfEvent1, kGenericPerfEvent2,
+                                      kGenericPerfEvent3})
+                    .IsValid());
+  }
+  EXPECT_FALSE(
+      PerfCounters::Create({kGenericPerfEvent2, "", kGenericPerfEvent1})
+          .IsValid());
+  EXPECT_FALSE(PerfCounters::Create({kGenericPerfEvent3, "not a counter name",
+                                     kGenericPerfEvent1})
+                   .IsValid());
+  {
+    EXPECT_TRUE(PerfCounters::Create({kGenericPerfEvent1, kGenericPerfEvent2,
+                                      kGenericPerfEvent3})
+                    .IsValid());
+  }
+  EXPECT_FALSE(
+      PerfCounters::Create({kGenericPerfEvent1, kGenericPerfEvent2,
+                            kGenericPerfEvent3, "MISPREDICTED_BRANCH_RETIRED"})
+          .IsValid());
+}
+
+TEST(PerfCountersTest, Read1Counter) {
+  if (!PerfCounters::kSupported) {
+    GTEST_SKIP() << "Test skipped because libpfm is not supported.\n";
+  }
+  EXPECT_TRUE(PerfCounters::Initialize());
+  auto counters = PerfCounters::Create({kGenericPerfEvent1});
+  EXPECT_TRUE(counters.IsValid());
+  PerfCounterValues values1(1);
+  EXPECT_TRUE(counters.Snapshot(&values1));
+  EXPECT_GT(values1[0], 0);
+  PerfCounterValues values2(1);
+  EXPECT_TRUE(counters.Snapshot(&values2));
+  EXPECT_GT(values2[0], 0);
+  EXPECT_GT(values2[0], values1[0]);
+}
+
+TEST(PerfCountersTest, Read2Counters) {
+  if (!PerfCounters::kSupported) {
+    GTEST_SKIP() << "Test skipped because libpfm is not supported.\n";
+  }
+  EXPECT_TRUE(PerfCounters::Initialize());
+  auto counters =
+      PerfCounters::Create({kGenericPerfEvent1, kGenericPerfEvent2});
+  EXPECT_TRUE(counters.IsValid());
+  PerfCounterValues values1(2);
+  EXPECT_TRUE(counters.Snapshot(&values1));
+  EXPECT_GT(values1[0], 0);
+  EXPECT_GT(values1[1], 0);
+  PerfCounterValues values2(2);
+  EXPECT_TRUE(counters.Snapshot(&values2));
+  EXPECT_GT(values2[0], 0);
+  EXPECT_GT(values2[1], 0);
+}
+
+size_t do_work() {
+  size_t res = 0;
+  for (size_t i = 0; i < 100000000; ++i) res += i * i;
+  return res;
+}
+
+void measure(size_t threadcount, PerfCounterValues* values1,
+             PerfCounterValues* values2) {
+  CHECK_NE(values1, nullptr);
+  CHECK_NE(values2, nullptr);
+  std::vector<std::thread> threads(threadcount);
+  auto work = [&]() { CHECK(do_work() > 1000); };
+
+  // We need to first set up the counters, then start the threads, so the
+  // threads would inherit the counters. But later, we need to first destroy the
+  // thread pool (so all the work finishes), then measure the counters. So the
+  // scopes overlap, and we need to explicitly control the scope of the
+  // threadpool.
+  auto counters =
+      PerfCounters::Create({kGenericPerfEvent1, kGenericPerfEvent3});
+  for (auto& t : threads) t = std::thread(work);
+  counters.Snapshot(values1);
+  for (auto& t : threads) t.join();
+  counters.Snapshot(values2);
+}
+
+TEST(PerfCountersTest, MultiThreaded) {
+  if (!PerfCounters::kSupported) {
+    GTEST_SKIP() << "Test skipped because libpfm is not supported.";
+  }
+  EXPECT_TRUE(PerfCounters::Initialize());
+  PerfCounterValues values1(2);
+  PerfCounterValues values2(2);
+
+  measure(2, &values1, &values2);
+  std::vector<double> D1{static_cast<double>(values2[0] - values1[0]),
+                         static_cast<double>(values2[1] - values1[1])};
+
+  measure(4, &values1, &values2);
+  std::vector<double> D2{static_cast<double>(values2[0] - values1[0]),
+                         static_cast<double>(values2[1] - values1[1])};
+
+  // Some extra work will happen on the main thread - like joining the threads
+  // - so the ratio won't be quite 2.0, but very close.
+  EXPECT_GE(D2[0], 1.9 * D1[0]);
+  EXPECT_GE(D2[1], 1.9 * D1[1]);
+}
+}  // namespace