add a performance benchmark test for the Buffer implementation

test/common/buffer/BUILD

@@ -3,6 +3,7 @@ licenses(["notice"])  # Apache 2
 load(
     "//bazel:envoy_build_system.bzl",
     "envoy_cc_test",
+    "envoy_cc_test_binary",
     "envoy_cc_test_library",
     "envoy_package",
 )
@@ -55,3 +56,14 @@ envoy_cc_test(
         "//source/common/buffer:zero_copy_input_stream_lib",
     ],
 )
+
+envoy_cc_test_binary(
+    name = "buffer_speed_test",
+    srcs = ["buffer_speed_test.cc"],
+    external_deps = [
+        "benchmark",
+    ],
+    deps = [
+        "//source/common/buffer:buffer_lib",
+    ],
+)

test/common/buffer/buffer_speed_test.cc

@@ -0,0 +1,221 @@
+#include "common/buffer/buffer_impl.h"
+#include "common/common/assert.h"
+
+#include "absl/strings/string_view.h"
+#include "testing/base/public/benchmark.h"
+
+namespace Envoy {
+
+// Test the creation of an empty OwnedImpl.
+static void BufferCreateEmpty(benchmark::State& state) {
+  uint64_t length = 0;
+  for (auto _ : state) {
+    Buffer::OwnedImpl buffer;
+    length += buffer.length();
+  }
+  benchmark::DoNotOptimize(length);
+}
+BENCHMARK(BufferCreateEmpty);
+
+// Test the creation of an OwnedImpl with varying amounts of content.
+static void BufferCreate(benchmark::State& state) {
+  const std::string data(state.range(0), 'a');
+  const absl::string_view input(data);
+  uint64_t length = 0;
+  for (auto _ : state) {
+    Buffer::OwnedImpl buffer(input);
+    length += buffer.length();
+  }
+  benchmark::DoNotOptimize(length);
+}
+BENCHMARK(BufferCreate)->Arg(1)->Arg(4096)->Arg(16384)->Arg(65536);
+
+// Test the appending of varying amounts of content from a string to an OwnedImpl.
+static void BufferAddString(benchmark::State& state) {
+  const std::string data(state.range(0), 'a');
+  const absl::string_view input(data);
+  Buffer::OwnedImpl buffer(input);
+  for (auto _ : state) {
+    buffer.add(data);
+    // Drain from the front of the Buffer to keep the test's memory usage fixed.
+    // @note Ideally we could use state.PauseTiming()/ResumeTiming() to exclude
+    // the time spent in the drain operation, but those functions themselves are
+    // heavyweight enough to cloud the measurements:
+    // https://github.com/google/benchmark/issues/179
+    buffer.drain(input.size());
+  }
+  uint64_t length = buffer.length();
+  benchmark::DoNotOptimize(length);
+}
+BENCHMARK(BufferAddString)->Arg(1)->Arg(4096)->Arg(16384)->Arg(65536);
+
+// Variant of BufferAddString that appends from another Buffer::Instance
+// rather than from a string.
+static void BufferAddBuffer(benchmark::State& state) {
+  const std::string data(state.range(0), 'a');
+  const absl::string_view input(data);
+  const Buffer::OwnedImpl to_add(data);
+  Buffer::OwnedImpl buffer(input);
+  for (auto _ : state) {
+    buffer.add(to_add);
+    // Drain from the front of the Buffer to keep the test's memory usage fixed.
+    buffer.drain(input.size());
+  }
+  uint64_t length = buffer.length();
+  benchmark::DoNotOptimize(length);
+}
+BENCHMARK(BufferAddBuffer)->Arg(1)->Arg(4096)->Arg(16384)->Arg(65536);
+
+static void BufferDrain(benchmark::State& state) {
+  const std::string data(state.range(0), 'a');
+  const absl::string_view input(data);
+  const Buffer::OwnedImpl to_add(data);
+  Buffer::OwnedImpl buffer(input);
+
+  // On each iteration of the benchmark, add N bytes and drain a multiple of N, as specified
+  // by DrainCycleRatios. This exercises full-slice, partial-slice, and multi-slice code paths
+  // in the Buffer's drain implementation.
+  constexpr size_t DrainCycleSize = 7;
+  constexpr double DrainCycleRatios[DrainCycleSize] = {0.0, 1.5, 1, 1.5, 0, 2.0, 1.0};
+  uint64_t drain_size[DrainCycleSize];
+  for (size_t i = 0; i < DrainCycleSize; i++) {
+    drain_size[i] = state.range(0) * DrainCycleRatios[i];
+  }
+
+  size_t drain_cycle = 0;
+  for (auto _ : state) {
+    buffer.add(to_add);
+    buffer.drain(drain_size[drain_cycle]);
+    drain_cycle++;
+    drain_cycle %= DrainCycleSize;
+  }
+  uint64_t length = buffer.length();
+  benchmark::DoNotOptimize(length);
+}
+BENCHMARK(BufferDrain)->Arg(1)->Arg(4096)->Arg(16384)->Arg(65536);
+
+// Test the moving of content from one OwnedImpl to another.
+static void BufferMove(benchmark::State& state) {
+  const std::string data(state.range(0), 'a');
+  const absl::string_view input(data);
+  Buffer::OwnedImpl buffer1(input);
+  Buffer::OwnedImpl buffer2(input);
+  for (auto _ : state) {
+    buffer1.move(buffer2); // now buffer1 has 2 copies of the input, and buffer2 is empty.
+    buffer2.move(buffer1, input.size()); // now buffer1 and buffer2 are the same size.
+  }
+  uint64_t length = buffer1.length();
+  benchmark::DoNotOptimize(length);
+}
+BENCHMARK(BufferMove)->Arg(1)->Arg(4096)->Arg(16384)->Arg(65536);
+
+// Test the moving of content from one OwnedImpl to another, one byte at a time, to
+// exercise the (likely inefficient) code path in the implementation that handles
+// partial moves.
+static void BufferMovePartial(benchmark::State& state) {
+  const std::string data(state.range(0), 'a');
+  const absl::string_view input(data);
+  Buffer::OwnedImpl buffer1(input);
+  Buffer::OwnedImpl buffer2(input);
+  for (auto _ : state) {
+    while (buffer2.length() != 0) {
+      buffer1.move(buffer2, 1);
+    }
+    buffer2.move(buffer1, input.size()); // now buffer1 and buffer2 are the same size.
+  }
+  uint64_t length = buffer1.length();
+  benchmark::DoNotOptimize(length);
+}
+BENCHMARK(BufferMovePartial)->Arg(1)->Arg(4096)->Arg(16384)->Arg(65536);
+
+// Test the reserve+commit cycle, for the special case where the reserved space is
+// fully used (and therefore the commit size equals the reservation size).
+static void BufferReserveCommit(benchmark::State& state) {
+  Buffer::OwnedImpl buffer;
+  for (auto _ : state) {
+    constexpr uint64_t NumSlices = 2;
+    Buffer::RawSlice slices[NumSlices];
+    uint64_t slices_used = buffer.reserve(state.range(0), slices, NumSlices);
+    uint64_t bytes_to_commit = 0;
+    for (uint64_t i = 0; i < slices_used; i++) {
+      bytes_to_commit += static_cast<uint64_t>(slices[i].len_);
+    }
+    buffer.commit(slices, slices_used);
+    buffer.drain(bytes_to_commit);
+  }
+  benchmark::DoNotOptimize(buffer.length());
+}
+BENCHMARK(BufferReserveCommit)->Arg(1)->Arg(4096)->Arg(16384)->Arg(65536);
+
+// Test the reserve+commit cycle, for the common case where the reserved space is
+// only partially used (and therefore the commit size is smaller than the reservation size).
+static void BufferReserveCommitPartial(benchmark::State& state) {
+  Buffer::OwnedImpl buffer;
+  for (auto _ : state) {
+    constexpr uint64_t NumSlices = 2;
+    Buffer::RawSlice slices[NumSlices];
+    uint64_t slices_used = buffer.reserve(state.range(0), slices, NumSlices);
+    ASSERT(slices_used > 0);
+    // Commit one byte from the first slice and nothing from any subsequent slice.
+    uint64_t bytes_to_commit = 1;
+    slices[0].len_ = bytes_to_commit;
+    buffer.commit(slices, 1);
+    buffer.drain(bytes_to_commit);
+  }
+  benchmark::DoNotOptimize(buffer.length());
+}
+BENCHMARK(BufferReserveCommitPartial)->Arg(1)->Arg(4096)->Arg(16384)->Arg(65536);
+
+// Test buffer search, for the simple case where there are no partial matches for
+// the pattern in the buffer.
+static void BufferSearch(benchmark::State& state) {
+  const std::string Pattern(16, 'b');
+  std::string data;
+  data.reserve(state.range(0) + Pattern.length());
+  data += std::string(state.range(0), 'a');
+  data += Pattern;
+
+  const absl::string_view input(data);
+  Buffer::OwnedImpl buffer(input);
+  ssize_t result = 0;
+  for (auto _ : state) {
+    result += buffer.search(Pattern.c_str(), Pattern.length(), 0);
+  }
+  benchmark::DoNotOptimize(result);
+}
+BENCHMARK(BufferSearch)->Arg(1)->Arg(4096)->Arg(16384)->Arg(65536);
+
+// Test buffer search, for the more challenging case where there are many partial matches
+// for the pattern in the buffer.
+static void BufferSearchPartialMatch(benchmark::State& state) {
+  const std::string Pattern(16, 'b');
+  const std::string PartialMatch("babbabbbabbbbabbbbbabbbbbbabbbbbbbabbbbbbbba");
+  std::string data;
+  size_t num_partial_matches = 1 + state.range(0) / PartialMatch.length();
+  data.reserve(state.range(0) * num_partial_matches + Pattern.length());
+  for (size_t i = 0; i < num_partial_matches; i++) {
+    data += PartialMatch;
+  }
+  data += Pattern;
+
+  const absl::string_view input(data);
+  Buffer::OwnedImpl buffer(input);
+  ssize_t result = 0;
+  for (auto _ : state) {
+    result += buffer.search(Pattern.c_str(), Pattern.length(), 0);
+  }
+  benchmark::DoNotOptimize(result);
+}
+BENCHMARK(BufferSearchPartialMatch)->Arg(1)->Arg(4096)->Arg(16384)->Arg(65536);
+
+} // namespace Envoy
+
+// Boilerplate main(), which discovers benchmarks in the same file and runs them.
+int main(int argc, char** argv) {
+  benchmark::Initialize(&argc, argv);
+
+  if (benchmark::ReportUnrecognizedArguments(argc, argv)) {
+    return 1;
+  }
+  benchmark::RunSpecifiedBenchmarks();
+}