dom/media/Tracing.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef TRACING_H
   8 #define TRACING_H
   9
  10 #include <algorithm>
  11 #include <cstdint>
  12 #include <cstdio>
  13
  14 #include "AsyncLogger.h"
  15
  16 #include "mozilla/Attributes.h"
  17 #include "mozilla/UniquePtr.h"
  18
  19 #if defined(_MSC_VER)
  20 // MSVC
  21 #  define FUNCTION_SIGNATURE __FUNCSIG__
  22 #elif defined(__GNUC__)
  23 // gcc, clang
  24 #  define FUNCTION_SIGNATURE __PRETTY_FUNCTION__
  25 #endif
  26
  27 extern mozilla::AsyncLogger gAudioCallbackTraceLogger;
  28
  29 // This is no-op if tracing is not enabled, and is idempotent.
  30 void StartAudioCallbackTracing();
  31 void StopAudioCallbackTracing();
  32
  33 #ifdef MOZ_REAL_TIME_TRACING
  34 #  define TRACE(aName) AutoTracer trace(gAudioCallbackTraceLogger, aName);
  35 #  define TRACE_COMMENT(aName, aFmt, ...)              \
  36     AutoTracer trace(gAudioCallbackTraceLogger, aName, \
  37                      AutoTracer::EventType::DURATION, aFmt, ##__VA_ARGS__);
  38 #  define TRACE_AUDIO_CALLBACK_BUDGET(id, aFrames, aSampleRate) \
  39     AutoTracer budget(gAudioCallbackTraceLogger, id,            \
  40                       AutoTracer::EventType::BUDGET, aFrames, aSampleRate);
  41 #else
  42 #  define TRACE(aName)
  43 #  define TRACE_COMMENT(aFmt, ...)
  44 #  define TRACE_AUDIO_CALLBACK_BUDGET(aFrames, aSampleRate)
  45 #endif
  46
  47 class MOZ_RAII AutoTracer {
  48  public:
  49   static const int32_t BUFFER_SIZE = 256;
  50
  51   enum class EventType { DURATION, BUDGET };
  52
  53   AutoTracer(mozilla::AsyncLogger& aLogger, const char* aLocation,
  54              EventType aEventType = EventType::DURATION,
  55              const char* aComment = nullptr);
  56
  57   template <typename... Args>
  58   AutoTracer(mozilla::AsyncLogger& aLogger, const char* aLocation,
  59              EventType aEventType, const char* aFormat, Args... aArgs)
  60       : mLogger(aLogger),
  61         mLocation(aLocation),
  62         mComment(mBuffer),
  63         mEventType(aEventType) {
  64     MOZ_ASSERT(aEventType == EventType::DURATION);
  65     if (aLogger.Enabled()) {
  66       int32_t size = snprintf(mBuffer, BUFFER_SIZE, aFormat, aArgs...);
  67       size = std::min(size, BUFFER_SIZE - 1);
  68       mBuffer[size] = 0;
  69       PrintEvent(aLocation, "perf", mComment,
  70                  mozilla::AsyncLogger::TracingPhase::BEGIN);
  71     }
  72   }
  73
  74   AutoTracer(mozilla::AsyncLogger& aLogger, const char* aLocation,
  75              EventType aEventType, uint64_t aFrames, uint64_t aSampleRate);
  76
  77   ~AutoTracer();
  78
  79  private:
  80   void PrintEvent(const char* aName, const char* aCategory,
  81                   const char* aComment,
  82                   mozilla::AsyncLogger::TracingPhase aPhase);
  83
  84   void PrintBudget(const char* aName, const char* aCategory, uint64_t aDuration,
  85                    uint64_t aFrames, uint64_t aSampleRate);
  86
  87   // The logger to use. It musdt have a lifetime longer than the block an
  88   // instance of this class traces.
  89   mozilla::AsyncLogger& mLogger;
  90   // The location for this trace point, arbitrary string literal, often the
  91   // name of the calling function, with a static lifetime.
  92   const char* mLocation;
  93   // A comment for this trace point, abitrary string literal with a static
  94   // lifetime.
  95   const char* mComment;
  96   // A buffer used to hold string-formatted traces.
  97   char mBuffer[BUFFER_SIZE];
  98   // The event type, for now either a budget or a duration.
  99   const EventType mEventType;
 100 };
 101
 102 #endif /* TRACING_H */