Add basic microbenchmarks.

PiperOrigin-RevId: 296104390

1 files changed, 62 insertions, 0 deletions

diff --git a/test/perf/linux/stat_benchmark.cc b/test/perf/linux/stat_benchmark.cc
new file mode 100644
index 000000000..f15424482
--- /dev/null
+++ b/test/perf/linux/stat_benchmark.cc
@@ -0,0 +1,62 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "gtest/gtest.h"
+#include "absl/strings/str_cat.h"
+#include "benchmark/benchmark.h"
+#include "test/util/fs_util.h"
+#include "test/util/temp_path.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+// Creates a file in a nested directory hierarchy at least `depth` directories
+// deep, and stats that file multiple times.
+void BM_Stat(benchmark::State& state) {
+  // Create nested directories with given depth.
+  int depth = state.range(0);
+  const TempPath top_dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
+  std::string dir_path = top_dir.path();
+
+  while (depth-- > 0) {
+    // Don't use TempPath because it will make paths too long to use.
+    //
+    // The top_dir destructor will clean up this whole tree.
+    dir_path = JoinPath(dir_path, absl::StrCat(depth));
+    ASSERT_NO_ERRNO(Mkdir(dir_path, 0755));
+  }
+
+  // Create the file that will be stat'd.
+  const TempPath file =
+      ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileIn(dir_path));
+
+  struct stat st;
+  for (auto _ : state) {
+    ASSERT_THAT(stat(file.path().c_str(), &st), SyscallSucceeds());
+  }
+}
+
+BENCHMARK(BM_Stat)->Range(1, 100)->UseRealTime();
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor