Introduce gpu_trace_event for gpu performance analysis.

gpu/common/gpu_trace_event.h

+// Copyright (c) 2010 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.
+
+// Trace events are for tracking application performance.
+//
+// Events are issued against categories. Whereas LOG's
+// categories are statically defined, TRACE categories are created
+// implicitly with a string. For example:
+//   GPU_TRACE_EVENT_INSTANT0("MY_SUBSYSTEM", "SomeImportantEvent")
+//
+// Events can be INSTANT, or can be pairs of BEGIN and END:
+//   GPU_TRACE_EVENT_BEGIN0("MY_SUBSYSTEM", "SomethingCostly")
+//   doSomethingCostly()
+//   GPU_TRACE_EVENT_END0("MY_SUBSYSTEM", "SomethingCostly")
+//
+// A common use case is to trace entire function scopes. This
+// issues a trace BEGIN and END automatically:
+//   void doSomethingCostly() {
+//     GPU_TRACE_EVENT0("MY_SUBSYSTEM", "doSomethingCostly");
+//     ...
+//   }
+//
+// Additional parameters can be associated with an event:
+//   void doSomethingCostly2(int howMuch) {
+//     GPU_TRACE_EVENT1("MY_SUBSYSTEM", "doSomethingCostly",
+//         "howMuch", StringPrintf("%i", howMuch).c_str());
+//     ...
+//   }
+//
+// The trace system will automatically add to this information the
+// current process id, thread id, a timestamp down to the
+// microsecond, as well as the file and line number of the calling location.
+//
+// By default, trace collection is compiled in, but turned off at runtime.
+// Collecting trace data is the responsibility of the embedding
+// application. In Chrome's case, navigating to about:gpu will turn on
+// tracing and display data collected across all active processes.
+//
+
+#ifndef GPU_TRACE_EVENT_H_
+#define GPU_TRACE_EVENT_H_
+#pragma once
+
+#include "build/build_config.h"
+
+#include <string>
+
+#include "base/scoped_ptr.h"
+#include "base/scoped_vector.h"
+#include "base/atomicops.h"
+#include "base/singleton.h"
+#include "base/time.h"
+#include "base/timer.h"
+#include "base/callback.h"
+#include <vector>
+
+
+// Implementation detail: trace event macros create temporary variables
+// to keep instrumentation overhead low. These macros give each temporary
+// variable a unique name based on the line number to prevent name collissions.
+#define GPU_TRACE_EVENT_UNIQUE_IDENTIFIER3(a,b) a##b
+#define GPU_TRACE_EVENT_UNIQUE_IDENTIFIER2(a,b) \
+  GPU_TRACE_EVENT_UNIQUE_IDENTIFIER3(a,b)
+#define GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(name_prefix) \
+  GPU_TRACE_EVENT_UNIQUE_IDENTIFIER2(name_prefix, __LINE__)
+
+// Records a pair of begin and end events called "name" for the current
+// scope, with 0, 1 or 2 associated arguments. If the category is not
+// enabled, then this does nothing.
+#define GPU_TRACE_EVENT0(category, name) \
+  GPU_TRACE_EVENT1(category, name, NULL, NULL)
+#define GPU_TRACE_EVENT1(category, name, arg1name, arg1val) \
+  GPU_TRACE_EVENT2(category, name, arg1name, arg1val, NULL, NULL)
+#define GPU_TRACE_EVENT2(category, name, arg1name, arg1val, arg2name, arg2val) \
+  static gpu::TraceCategory* \
+      GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic) = \
+      gpu::TraceLog::GetInstance()->GetCategory(category); \
+  if (base::subtle::Acquire_Load(\
+      &(GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic))->enabled_)) { \
+    gpu::TraceLog::GetInstance()->AddTraceEvent( \
+        gpu::GPU_TRACE_EVENT_PHASE_BEGIN, \
+        __FILE__, __LINE__, \
+        GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic), \
+        name, \
+        arg1name, arg1val, \
+        arg2name, arg2val); \
+  } \
+  gpu::internal::TraceEndOnScopeClose __profileScope ## __LINE ( \
+      __FILE__, __LINE__, \
+      GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic), name);
+
+// Records a single event called "name" immediately, with 0, 1 or 2
+// associated arguments. If the category is not enabled, then this
+// does nothing.
+#define GPU_TRACE_EVENT_INSTANT0(category, name) \
+  GPU_TRACE_EVENT_INSTANT1(category, name, NULL, NULL)
+#define GPU_TRACE_EVENT_INSTANT1(category, name, arg1name, arg1val) \
+  GPU_TRACE_EVENT_INSTANT2(category, name, arg1name, arg1val, NULL, NULL)
+#define GPU_TRACE_EVENT_INSTANT2(category, name, arg1name, arg1val, \
+    arg2name, arg2val) \
+  static gpu::TraceCategory* \
+      GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic) = \
+      gpu::TraceLog::GetInstance()->GetCategory(category); \
+  if (base::subtle::Acquire_Load( \
+      &(GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic))->enabled_)) { \
+    gpu::TraceLog::GetInstance()->AddTraceEvent( \
+        gpu::GPU_TRACE_EVENT_PHASE_INSTANT, \
+        __FILE__, __LINE__, \
+        GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic), \
+        name, \
+        arg1name, arg1val, \
+        arg2name, arg2val); \
+  }
+
+// Records a single BEGIN event called "name" immediately, with 0, 1 or 2
+// associated arguments. If the category is not enabled, then this
+// does nothing.
+#define GPU_TRACE_EVENT_BEGIN0(category, name) \
+  GPU_TRACE_EVENT_BEGIN1(category, name, NULL, NULL)
+#define GPU_TRACE_EVENT_BEGIN1(category, name, arg1name, arg1val) \
+  GPU_TRACE_EVENT_BEGIN2(category, name, arg1name, arg1val, NULL, NULL)
+#define GPU_TRACE_EVENT_BEGIN2(category, name, arg1name, arg1val, \
+    arg2name, arg2val) \
+  static gpu::TraceCategory* \
+      GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic) = \
+      gpu::TraceLog::GetInstance()->GetCategory(category); \
+  if (base::subtle::Acquire_Load( \
+      &(GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic))->enabled_)) { \
+    gpu::TraceLog::GetInstance()->AddTraceEvent( \
+        gpu::GPU_TRACE_EVENT_PHASE_BEGIN, \
+        __FILE__, __LINE__, \
+        GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic), \
+        name, \
+        arg1name, arg1val, \
+        arg2name, arg2val); \
+  }
+
+// Records a single END event for "name" immediately. If the category
+// is not enabled, then this does nothing.
+#define GPU_TRACE_EVENT_END0(category, name) \
+  static gpu::TraceCategory* \
+      GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic) = \
+      gpu::TraceLog::GetInstance()->GetCategory(category); \
+  if (base::subtle::Acquire_Load( \
+      &(GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic))->enabled_)) {  \
+    gpu::TraceLog::GetInstance()->AddTraceEvent( \
+        gpu::GPU_TRACE_EVENT_PHASE_END, \
+        __FILE__, __LINE__, \
+        GPU_TRACE_EVENT_UNIQUE_IDENTIFIER(catstatic), \
+        name, \
+        arg1name, arg1val, \
+        arg2name, arg2val); \
+  }
+
+
+namespace gpu {
+
+// Categories allow enabling/disabling of streams of trace events
+// Don't manipulate the category object directly, as this may lead
+// to threading issues. Use the TraceLog methods instead.
+class TraceCategory {
+ public:
+  TraceCategory(const char* name, bool enabled);
+  ~TraceCategory();
+
+  const char* name() const { return name_; }
+
+  // NEVER read these directly, let the macros do it for you
+  volatile base::subtle::Atomic32 enabled_;
+ protected:
+  const char* name_;
+};
+
+#define TRACE_MAX_NUM_ARGS 2
+
+enum TraceEventPhase {
+  GPU_TRACE_EVENT_PHASE_BEGIN,
+  GPU_TRACE_EVENT_PHASE_END,
+  GPU_TRACE_EVENT_PHASE_INSTANT
+};
+
+// Output records are "Events" and can be obtained via the
+// OutputCallback whenever the logging system decides to flush. This
+// can happen at any time, on any thread, or you can programatically
+// force it to happen.
+struct TraceEvent {
+  static void AppendAsJSON(std::string* out,
+      const std::vector<TraceEvent>& events);
+  void AppendAsJSON(std::string* out) const;
+
+
+  unsigned long processId;
+  unsigned long threadId;
+  base::TimeTicks timestamp;
+  TraceEventPhase phase;
+  TraceCategory* category;
+  const char* name;
+  const char* argNames[TRACE_MAX_NUM_ARGS];
+  std::string argValues[TRACE_MAX_NUM_ARGS];
+};
+
+
+class TraceLog {
+ public:
+  static TraceLog* GetInstance();
+
+  // Global enable of tracing. Currently enables all categories or not.
+  // TODO(nduca) Replaced with an Enable/DisableCategory() that
+  // implicitly controls the global logging state.
+  void SetEnabled(bool enabled);
+
+  // When enough events are collected, they are handed (in bulk) to
+  // the output callback. If no callback is set, the output will be
+  // silently dropped.
+  typedef Callback1<const std::string& /* json_events */>::Type OutputCallback;
+  void SetOutputCallback(OutputCallback* cb);
+
+  // Forwards data collected by a child process to the registered
+  //  output callback.
+  void AddRemotelyCollectedData(const std::string& json_events);
+
+  // Flushes all logged data to the callback.
+  void Flush();
+
+  // Called by GPU_TRACE_EVENT* macros, don't call this directly.
+  TraceCategory* GetCategory(const char* name);
+
+  // Called by GPU_TRACE_EVENT* macros, don't call this directly.
+  void AddTraceEvent(TraceEventPhase phase,
+      const char* file, int line,
+      TraceCategory* category,
+      const char* name,
+      const char* arg1name, const char* arg1val,
+      const char* arg2name, const char* arg2val);
+
+ private:
+  // This allows constructor and destructor to be private and usable only
+  // by the Singleton class.
+  friend struct StaticMemorySingletonTraits<TraceLog>;
+
+  TraceLog();
+  ~TraceLog();
+  void FlushWithLockAlreadyHeld();
+
+  // TODO(nduca): switch to per-thread trace buffers to reduce thread
+  // synchronization.
+  base::Lock lock_;
+  bool enabled_;
+  ScopedVector<TraceCategory> categories_;
+  scoped_ptr<OutputCallback> output_callback_;
+  std::vector<TraceEvent> logged_events_;
+
+  DISALLOW_COPY_AND_ASSIGN(TraceLog);
+};
+
+namespace internal {
+
+// Used by GPU_TRACE_EVENTx macro. Do not use directly.
+class TraceEndOnScopeClose {
+ public:
+  TraceEndOnScopeClose(const char* file, int line,
+                       TraceCategory* category,
+                       const char* name)
+      : file_(file)
+      , line_(line)
+      , category_(category)
+      , name_(name) { }
+
+  ~TraceEndOnScopeClose() {
+    if (base::subtle::Acquire_Load(&category_->enabled_))
+      gpu::TraceLog::GetInstance()->AddTraceEvent(
+          gpu::GPU_TRACE_EVENT_PHASE_END,
+          file_, line_,
+          category_,
+          name_,
+          NULL, NULL, NULL, NULL);
+  }
+
+ private:
+  const char* file_;
+  int line_;
+  TraceCategory* category_;
+  const char* name_;
+};
+
+}  // namespace internal
+
+}  // namespace gpu
+
+#endif  // GPU_TRACE_EVENT_H_