| /* |
| * Copyright 2018 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #pragma once |
| |
| #include <chrono> |
| #include <cinttypes> |
| #include <numeric> |
| #include <unordered_map> |
| #include <vector> |
| |
| namespace android { |
| namespace scheduler { |
| using namespace std::chrono_literals; |
| |
| // This number is used to set the size of the arrays in scheduler that hold information |
| // about layers. |
| static constexpr size_t ARRAY_SIZE = 30; |
| |
| // This number is used to have a place holder for when the screen is not NORMAL/ON. Currently |
| // the config is not visible to SF, and is completely maintained by HWC. However, we would |
| // still like to keep track of time when the device is in this config. |
| static constexpr int SCREEN_OFF_CONFIG_ID = -1; |
| static constexpr uint32_t HWC2_SCREEN_OFF_CONFIG_ID = 0xffffffff; |
| |
| // This number is used when we try to determine how long does a given layer stay relevant. |
| // Currently it is set to 100ms, because that would indicate 10Hz rendering. |
| static constexpr std::chrono::nanoseconds TIME_EPSILON_NS = 100ms; |
| |
| // This number is used when we try to determine how long do we keep layer information around |
| // before we remove it. Currently it is set to 100ms. |
| static constexpr std::chrono::nanoseconds OBSOLETE_TIME_EPSILON_NS = 100ms; |
| |
| // Calculates the statistical mean (average) in the data structure (array, vector). The |
| // function does not modify the contents of the array. |
| template <typename T> |
| auto calculate_mean(const T& v) { |
| using V = typename T::value_type; |
| V sum = std::accumulate(v.begin(), v.end(), static_cast<V>(0)); |
| return sum / static_cast<V>(v.size()); |
| } |
| |
| // Calculates the statistical median in the vector. Return 0 if the vector is empty. The |
| // function modifies the vector contents. |
| int64_t calculate_median(std::vector<int64_t>* v); |
| |
| // Calculates the statistical mode in the vector. Return 0 if the vector is empty. |
| template <typename T> |
| auto calculate_mode(const T& v) { |
| if (v.empty()) { |
| return 0; |
| } |
| |
| // Create a map with all the counts for the indivicual values in the vector. |
| std::unordered_map<int64_t, int> counts; |
| for (int64_t value : v) { |
| counts[value]++; |
| } |
| |
| // Sort the map, and return the number with the highest count. If two numbers have |
| // the same count, first one is returned. |
| using ValueType = const decltype(counts)::value_type&; |
| const auto compareCounts = [](ValueType l, ValueType r) { return l.second <= r.second; }; |
| return static_cast<int>(std::max_element(counts.begin(), counts.end(), compareCounts)->first); |
| } |
| |
| } // namespace scheduler |
| } // namespace android |