Repo created

TMessagesProj/jni/voip/webrtc/absl/random/internal/nanobenchmark_test.cc

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+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// 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
+//
+//     https://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 "absl/random/internal/nanobenchmark.h"
+
+#include "absl/log/check.h"
+#include "absl/log/log.h"
+#include "absl/strings/numbers.h"
+#include "absl/strings/str_format.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace random_internal_nanobenchmark {
+namespace {
+
+uint64_t Div(const void*, FuncInput in) {
+  // Here we're measuring the throughput because benchmark invocations are
+  // independent.
+  const int64_t d1 = 0xFFFFFFFFFFll / int64_t(in);  // IDIV
+  return d1;
+}
+
+template <size_t N>
+void MeasureDiv(const FuncInput (&inputs)[N]) {
+  Result results[N];
+  Params params;
+  params.max_evals = 6;  // avoid test timeout
+  const size_t num_results = Measure(&Div, nullptr, inputs, N, results, params);
+  if (num_results == 0) {
+    LOG(WARNING)
+        << "WARNING: Measurement failed, should not happen when using "
+           "PinThreadToCPU unless the region to measure takes > 1 second.";
+    return;
+  }
+  for (size_t i = 0; i < num_results; ++i) {
+    LOG(INFO) << absl::StreamFormat("%5u: %6.2f ticks; MAD=%4.2f%%\n",
+                                    results[i].input, results[i].ticks,
+                                    results[i].variability * 100.0);
+    CHECK_NE(results[i].ticks, 0.0f) << "Zero duration";
+  }
+}
+
+void RunAll(const int argc, char* argv[]) {
+  // Avoid migrating between cores - important on multi-socket systems.
+  int cpu = -1;
+  if (argc == 2) {
+    if (!absl::SimpleAtoi(argv[1], &cpu)) {
+      LOG(FATAL) << "The optional argument must be a CPU number >= 0.";
+    }
+  }
+  PinThreadToCPU(cpu);
+
+  // unpredictable == 1 but the compiler doesn't know that.
+  const FuncInput unpredictable = argc != 999;
+  static const FuncInput inputs[] = {unpredictable * 10, unpredictable * 100};
+
+  MeasureDiv(inputs);
+}
+
+}  // namespace
+}  // namespace random_internal_nanobenchmark
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+int main(int argc, char* argv[]) {
+  absl::random_internal_nanobenchmark::RunAll(argc, argv);
+  return 0;
+}