cc/debug/latency_info.cc

   1 // Copyright (c) 2013 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 #include "cc/debug/latency_info.h"
   6
   7 #include <algorithm>
   8
   9 namespace cc {
  10
  11 LatencyInfo::LatencyInfo() {
  12 }
  13
  14 LatencyInfo::~LatencyInfo() {
  15 }
  16
  17 void LatencyInfo::MergeWith(const LatencyInfo& other) {
  18   for (LatencyMap::const_iterator b = other.latency_components.begin();
  19       b != other.latency_components.end(); ++b) {
  20     AddLatencyNumberWithTimestamp(b->first.first, b->first.second,
  21                                   b->second.sequence_number,
  22                                   b->second.event_time,
  23                                   b->second.event_count);
  24   }
  25 }
  26
  27 void LatencyInfo::AddLatencyNumber(LatencyComponentType component,
  28                                    int64 id, int64 component_sequence_number) {
  29   AddLatencyNumberWithTimestamp(component, id, component_sequence_number,
  30                                 base::TimeTicks::Now(), 1);
  31 }
  32
  33 void LatencyInfo::AddLatencyNumberWithTimestamp(
  34     LatencyComponentType component, int64 id, int64 component_sequence_number,
  35     base::TimeTicks time, uint32 event_count) {
  36   LatencyMap::key_type key = std::make_pair(component, id);
  37   LatencyMap::iterator f = latency_components.find(key);
  38   if (f == latency_components.end()) {
  39     LatencyComponent info = {component_sequence_number, time, event_count};
  40     latency_components[key] = info;
  41   } else {
  42     f->second.sequence_number = std::max(component_sequence_number,
  43                                          f->second.sequence_number);
  44     uint32 new_count = event_count + f->second.event_count;
  45     if (event_count > 0 && new_count != 0) {
  46       // Do a weighted average, so that the new event_time is the average of
  47       // the times of events currently in this structure with the time passed
  48       // into this method.
  49       f->second.event_time += (time - f->second.event_time) * event_count /
  50           new_count;
  51       f->second.event_count = new_count;
  52     }
  53   }
  54 }
  55
  56 void LatencyInfo::Clear() {
  57   latency_components.clear();
  58 }
  59
  60 }  // namespace cc
  61