1 // Copyright 2014 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 <cmath> 6 7 #include "cc/base/rolling_time_delta_history.h" 8 9 namespace cc { 10 11 RollingTimeDeltaHistory::RollingTimeDeltaHistory(size_t max_size) 12 : max_size_(max_size) {} 13 14 RollingTimeDeltaHistory::~RollingTimeDeltaHistory() {} 15 16 void RollingTimeDeltaHistory::InsertSample(base::TimeDelta time) { 17 if (max_size_ == 0) 18 return; 19 20 if (sample_set_.size() == max_size_) { 21 sample_set_.erase(chronological_sample_deque_.front()); 22 chronological_sample_deque_.pop_front(); 23 } 24 25 TimeDeltaMultiset::iterator it = sample_set_.insert(time); 26 chronological_sample_deque_.push_back(it); 27 } 28 29 void RollingTimeDeltaHistory::Clear() { 30 chronological_sample_deque_.clear(); 31 sample_set_.clear(); 32 } 33 34 base::TimeDelta RollingTimeDeltaHistory::Percentile(double percent) const { 35 if (sample_set_.size() == 0) 36 return base::TimeDelta(); 37 38 double fraction = percent / 100.0; 39 40 if (fraction <= 0.0) 41 return *(sample_set_.begin()); 42 43 if (fraction >= 1.0) 44 return *(sample_set_.rbegin()); 45 46 size_t num_smaller_samples = 47 static_cast<size_t>(std::ceil(fraction * sample_set_.size())) - 1; 48 49 if (num_smaller_samples > sample_set_.size() / 2) { 50 size_t num_larger_samples = sample_set_.size() - num_smaller_samples - 1; 51 TimeDeltaMultiset::const_reverse_iterator it = sample_set_.rbegin(); 52 for (size_t i = 0; i < num_larger_samples; i++) 53 it++; 54 return *it; 55 } 56 57 TimeDeltaMultiset::const_iterator it = sample_set_.begin(); 58 for (size_t i = 0; i < num_smaller_samples; i++) 59 it++; 60 return *it; 61 } 62 63 } // namespace cc 64
