cc/debug/frame_timing_tracker.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CC_DEBUG_FRAME_TIMING_TRACKER_H_
   6 #define CC_DEBUG_FRAME_TIMING_TRACKER_H_
   7
   8 #include <utility>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/containers/hash_tables.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/time/time.h"
  15 #include "cc/base/cc_export.h"
  16
  17 namespace cc {
  18
  19 // This class maintains a history of timestamps and rect IDs to communicate
  20 // frame events back to Blink
  21 // TODO(mpb): Start using this. crbug.com/442554
  22 class CC_EXPORT FrameTimingTracker {
  23  public:
  24   struct CC_EXPORT CompositeTimingEvent {
  25     CompositeTimingEvent(int, base::TimeTicks);
  26     ~CompositeTimingEvent();
  27
  28     int frame_id;
  29     base::TimeTicks timestamp;
  30   };
  31
  32   using CompositeTimingSet =
  33       base::hash_map<int, std::vector<CompositeTimingEvent>>;
  34
  35   static scoped_ptr<FrameTimingTracker> Create();
  36
  37   ~FrameTimingTracker();
  38
  39   // This routine takes all of the individual CompositeEvents stored in the
  40   // tracker and collects them by "rect_id", as in the example below.
  41   // [ {f_id1,r_id1,t1}, {f_id2,r_id1,t2}, {f_id3,r_id2,t3} ]
  42   // ====>
  43   // [ {r_id1,<{f_id1,t1},{f_id2,t2}>}, {r_id2,<{f_id3,t3}>} ]
  44   scoped_ptr<CompositeTimingSet> GroupCountsByRectId();
  45
  46   // This routine takes a timestamp and an array of frame_id,rect_id pairs
  47   // and generates CompositeTimingEvents (frame_id, timestamp) and adds them to
  48   // internal hash_map keyed on rect_id
  49   using FrameAndRectIds = std::pair<int, int64_t>;
  50   void SaveTimeStamps(base::TimeTicks timestamp,
  51                       const std::vector<FrameAndRectIds>& frame_ids);
  52
  53  private:
  54   FrameTimingTracker();
  55
  56   scoped_ptr<CompositeTimingSet> composite_events_;
  57
  58   DISALLOW_COPY_AND_ASSIGN(FrameTimingTracker);
  59 };
  60
  61 }  // namespace cc
  62
  63 #endif  // CC_DEBUG_FRAME_TIMING_TRACKER_H_