| /* |
| * Copyright (C) 2019 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. |
| */ |
| |
| #include <input/LatencyStatistics.h> |
| |
| #include <android-base/chrono_utils.h> |
| |
| #include <cmath> |
| #include <limits> |
| |
| namespace android { |
| |
| LatencyStatistics::LatencyStatistics(std::chrono::seconds period) : mReportPeriod(period) { |
| reset(); |
| } |
| |
| /** |
| * Add a raw value to the statistics |
| */ |
| void LatencyStatistics::addValue(float value) { |
| if (value < mMin) { |
| mMin = value; |
| } |
| if (value > mMax) { |
| mMax = value; |
| } |
| mSum += value; |
| mSum2 += value * value; |
| mCount++; |
| } |
| |
| /** |
| * Get the mean. Should not be called if no samples have been added. |
| */ |
| float LatencyStatistics::getMean() { |
| return mSum / mCount; |
| } |
| |
| /** |
| * Get the standard deviation. Should not be called if no samples have been added. |
| */ |
| float LatencyStatistics::getStDev() { |
| float mean = getMean(); |
| return sqrt(mSum2 / mCount - mean * mean); |
| } |
| |
| float LatencyStatistics::getMin() { |
| return mMin; |
| } |
| |
| float LatencyStatistics::getMax() { |
| return mMax; |
| } |
| |
| size_t LatencyStatistics::getCount() { |
| return mCount; |
| } |
| |
| /** |
| * Reset internal state. The variable 'when' is the time when the data collection started. |
| * Call this to start a new data collection window. |
| */ |
| void LatencyStatistics::reset() { |
| mMax = std::numeric_limits<float>::lowest(); |
| mMin = std::numeric_limits<float>::max(); |
| mSum = 0; |
| mSum2 = 0; |
| mCount = 0; |
| mLastReportTime = std::chrono::steady_clock::now(); |
| } |
| |
| bool LatencyStatistics::shouldReport() { |
| std::chrono::duration timeSinceReport = std::chrono::steady_clock::now() - mLastReportTime; |
| return mCount != 0 && timeSinceReport >= mReportPeriod; |
| } |
| |
| } // namespace android |