Add a simple microbenchmark framework, packaging, and sample tests.

src/platform/microbenchmark/microbenchmark.h

Index: src/platform/microbenchmark/microbenchmark.h
diff --git a/src/platform/microbenchmark/microbenchmark.h b/src/platform/microbenchmark/microbenchmark.h
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+// Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+// Some portions Copyright (c) 2009 The Chromium Authors.
+//
+// Simple microbenchmark framework
+
+#ifndef __CHROMEOS_MICROBENCHMARK_MICROBENCHMARK_H
+#define __CHROMEOS_MICROBENCHMARK_MICROBENCHMARK_H
+
+#include <errno.h>
+#include <time.h>
+
+#include <iostream>
+
+#include <base/basictypes.h>
+#include <base/command_line.h>
+#include <base/logging.h>
+#include <base/scoped_ptr.h>
+#include <gtest/gtest.h>
+
+#define CHROMEOS_MICROBENCHMARK_WITH_SETUP(_SETUP_NAME, _NAME, _RUNS) \
+class _NAME ## Class : public Microbenchmark { \
+ public: \
+  _NAME ## Class() {} \
+  ~_NAME ## Class() {} \
+  const char *name() const { return #_NAME; } \
+  void Setup(uint64 runs) { _SETUP_NAME(runs); } \
+  void SingleTest(bool scaffold_only) { _NAME(scaffold_only); } \
+}; \
+TEST(_NAME, Microbenchmark) { \
+  _NAME ## Class chromeos_benchmark; \
+  CommandLine *cl = CommandLine::ForCurrentProcess(); \
+  errno = 0; \
+  std::string runs_str = \
+    cl->GetSwitchValueASCII(chromeos::Microbenchmark::kRunsSwitch); \
+  unsigned long long runs = _RUNS; \
+  if (!runs_str.empty()) { \
+    errno = 0; \
+    runs = strtoull(runs_str.c_str(), NULL, 0); \
+    if (errno) \
+      runs = _RUNS; \
+   } \
+  chromeos_benchmark.Run(runs); \
+  chromeos_benchmark.Print(); \
+}
+
+#define CHROMEOS_MICROBENCHMARK(_NAME, _RUNS) \
+  CHROMEOS_MICROBENCHMARK_WITH_SETUP(chromeos::microbenchmark_helper::NoSetup, \
+                                     _NAME, \
+                                     _RUNS)
+namespace chromeos {
+
+namespace microbenchmark_helper {
+void NoSetup(uint64 runs);
+}  // microbenchmark
+
+// A simple microbenchmarking abstract class.
+// This class is not thread-safe and should only be invoked
+// from one thread at a time.
+class Microbenchmark {
+ public:
+   Microbenchmark() : scaffold_total_ns_(0),
+                      scaffold_per_run_ns_(0),
+                      total_ns_(0),
+                      per_run_ns_(0),
+                      runs_(0) {}
+   virtual ~Microbenchmark() {}
+   // Switch to override the number of runs to perform.
+   static const char *kRunsSwitch;
+   // Performs the actual microbenchmarking.
+   void Run(uint64 number_of_runs);
+   // Outputs a standard format of the testing data to stdout.
+   void Print() const;
+   // Accessors
+   const uint64 total_nanoseconds() const { return total_ns_; }
+   const uint64 per_run_nanoseconds() const { return per_run_ns_; }
+   const uint64 scaffold_total_nanoseconds() const
+     { return scaffold_total_ns_; }
+   const uint64 scaffold_per_run_nanoseconds() const
+     { return scaffold_per_run_ns_; }
+   const uint64 runs() const { return runs_; }
+
+   //// Test code to be implemented by the class consumer.
+   virtual const char *name() const = 0;
+   // Called automatically before the benchmark.
+   virtual void Setup(uint64 runs) = 0;
+   // Should execute the test to benchmark once.
+   virtual void SingleTest(bool scaffold_only) = 0;
+
+ private:
+  uint64 scaffold_total_ns_;
+  uint64 scaffold_per_run_ns_;
+  uint64 total_ns_;
+  uint64 per_run_ns_;
+  uint64 runs_;
+  DISALLOW_COPY_AND_ASSIGN(Microbenchmark);
+};
+
+}  // chromeos
+#endif  // __CHROMEOS_MICROBENCHMARK_MICROBENCHMARK_H