Add basic microbenchmarks.

PiperOrigin-RevId: 296104390

1 files changed, 66 insertions, 0 deletions

diff --git a/test/perf/linux/seqwrite_benchmark.cc b/test/perf/linux/seqwrite_benchmark.cc
new file mode 100644
index 000000000..af49e4477
--- /dev/null
+++ b/test/perf/linux/seqwrite_benchmark.cc
@@ -0,0 +1,66 @@
+// 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 <fcntl.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "gtest/gtest.h"
+#include "benchmark/benchmark.h"
+#include "test/util/logging.h"
+#include "test/util/temp_path.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+// The maximum file size of the test file, when writes get beyond this point
+// they wrap around. This should be large enough to blow away caches.
+const uint64_t kMaxFile = 1 << 30;
+
+// Perform writes of various sizes sequentially to one file. Wraps around if it
+// goes above a certain maximum file size.
+void BM_SeqWrite(benchmark::State& state) {
+  auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
+  FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_WRONLY));
+
+  const int size = state.range(0);
+  std::vector<char> buf(size);
+  RandomizeBuffer(buf.data(), buf.size());
+
+  // Start writes at offset 0.
+  uint64_t offset = 0;
+  for (auto _ : state) {
+    TEST_CHECK(PwriteFd(fd.get(), buf.data(), buf.size(), offset) ==
+               buf.size());
+    offset += buf.size();
+    // Wrap around if going above the maximum file size.
+    if (offset >= kMaxFile) {
+      offset = 0;
+    }
+  }
+
+  state.SetBytesProcessed(static_cast<int64_t>(size) *
+                          static_cast<int64_t>(state.iterations()));
+}
+
+BENCHMARK(BM_SeqWrite)->Range(1, 1 << 26)->UseRealTime();
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor