Temporary commit to evaluate perf impact of prototype CPU profiler

base/profiler/cpu_profiler.h

Index: base/profiler/cpu_profiler.h
diff --git a/base/profiler/cpu_profiler.h b/base/profiler/cpu_profiler.h
new file mode 100644
index 0000000000000000000000000000000000000000..6ce17713d4ec0373c5f47198984b4e7e6d7c62b5
--- /dev/null
+++ b/base/profiler/cpu_profiler.h
@@ -0,0 +1,104 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+

[cpu_(ooo_6.6-7.5), 2015/02/03 02:40:53]

remove line at 5

[Mike Wittman, 2015/02/04 01:37:09]

Done.

+#ifndef BASE_PROFILER_CPU_PROFILER_H_
+#define BASE_PROFILER_CPU_PROFILER_H_
+
+#include <map>
+
+#include "base/base_export.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/string16.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/timer/timer.h"
+
+#if defined(OS_WIN)
+struct _CONTEXT;
+#endif
+
+namespace base {
+
+class SamplingThread : public PlatformThread::Delegate {
+ public:
+  SamplingThread();
+  ~SamplingThread() override;
+
+  // Implementation of PlatformThread::Delegate:
+  void ThreadMain() override;
+
+  void Stop();
+
+  void GetSamples();
+
+ private:
+  bool thread_running_;
+
+  base::WaitableEvent waitable_event_;

[cpu_(ooo_6.6-7.5), 2015/02/03 02:40:53]

disable copy ctor and assignment 

[Mike Wittman, 2015/02/04 01:37:09]

Done.

+};
+
+class BASE_EXPORT CpuProfiler {
+ public:
+  static void Initialize(const std::map<std::string, std::string>& params);
+  static CpuProfiler* GetInstance();
+  static bool IsPlatformSupported();
+  static void Stop();
+
+  std::string GetStringParam(const std::string& key);
+  int GetIntParam(const std::string& key);
+  int64 GetInt64Param(const std::string& key);
+
+  void OnTimer();
+
+ private:
+  CpuProfiler();
+  ~CpuProfiler();
+
+  void SetParams(const std::map<std::string, std::string>& params);
+
+  void GetThreadIds();
+
+#if defined(OS_WIN)
+  struct StackTraceEntry {
+    DWORD64 rsp;
+    DWORD64 rip;
+    HMODULE module;
+  };
+
+  int SampleThread(DWORD thread, int max_stack_size, StackTraceEntry* stack);
+
+  static int StackTrace64(_CONTEXT* context, int stack_depth,
+      StackTraceEntry* stack_trace);
+
+  static void GetNames(StackTraceEntry* stack_trace, int stack_depth);
+
+  void ResolveModules();
+
+  void ProcessStack(StackTraceEntry* stack, int stack_depth);
+
+  DWORD ui_thread_;
+  DWORD io_thread_;

[cpu_(ooo_6.6-7.5), 2015/02/03 02:40:53]

are these two dwords the thread id? seems kind of racy, unless you assume they
never die, which is a weird knowledge at the /base level.

If it can't be a thread handle and it must be an id, then use xx_thread_id here
and elsewhere and for the handle itself use xxx_thread or xx_thread_handle.

[Mike Wittman, 2015/02/04 01:37:09]

Changed to use a handle.

+
+  int ui_thread_stack_depth_;
+  StackTraceEntry ui_thread_stack_[64];
+
+  int io_thread_stack_depth_;
+  StackTraceEntry io_thread_stack_[64];
+
+  std::map<HMODULE, base::string16> modules_;
+#endif
+
+  static CpuProfiler* g_instance_;
+
+  typedef std::map<std::string, std::string> Map;
+  Map params_;

[cpu_(ooo_6.6-7.5), 2015/02/03 02:40:53]

you can use auto, which should eliminate most needs for these kind of typedefs.

[Mike Wittman, 2015/02/04 01:37:09]

Done.

+
+  scoped_ptr<SamplingThread> sampling_thread_;
+  PlatformThreadHandle sampling_thread_handle_;
+};
+
+}
+
+
+#endif   // BASE_PROFILER_CPU_PROFILER_H_