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- /*
- * Copyright 2018-present Facebook, Inc.
- *
- * 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 <folly/stats/TDigest.h>
- #include <folly/stats/detail/BufferedStat.h>
- namespace folly {
- struct QuantileEstimates {
- public:
- double sum;
- double count;
- // vector of {quantile, value}
- std::vector<std::pair<double, double>> quantiles;
- };
- /*
- * A QuantileEstimator that buffers writes for 1 second.
- */
- template <typename ClockT = std::chrono::steady_clock>
- class SimpleQuantileEstimator {
- public:
- using TimePoint = typename ClockT::time_point;
- SimpleQuantileEstimator();
- QuantileEstimates estimateQuantiles(
- Range<const double*> quantiles,
- TimePoint now = ClockT::now());
- void addValue(double value, TimePoint now = ClockT::now());
- /// Flush buffered values
- void flush() {
- bufferedDigest_.flush();
- }
- private:
- detail::BufferedDigest<TDigest, ClockT> bufferedDigest_;
- };
- /*
- * A QuantileEstimator that keeps values for nWindows * windowDuration (see
- * constructor). Values are buffered for windowDuration.
- */
- template <typename ClockT = std::chrono::steady_clock>
- class SlidingWindowQuantileEstimator {
- public:
- using TimePoint = typename ClockT::time_point;
- SlidingWindowQuantileEstimator(
- std::chrono::seconds windowDuration,
- size_t nWindows = 60);
- QuantileEstimates estimateQuantiles(
- Range<const double*> quantiles,
- TimePoint now = ClockT::now());
- void addValue(double value, TimePoint now = ClockT::now());
- /// Flush buffered values
- void flush() {
- bufferedSlidingWindow_.flush();
- }
- private:
- detail::BufferedSlidingWindow<TDigest, ClockT> bufferedSlidingWindow_;
- };
- extern template class SimpleQuantileEstimator<std::chrono::steady_clock>;
- extern template class SlidingWindowQuantileEstimator<std::chrono::steady_clock>;
- } // namespace folly
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