/src/brpc/src/bvar/detail/sampler.h

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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.

// Date: Tue Jul 28 18:15:57 CST 2015

#ifndef  BVAR_DETAIL_SAMPLER_H
#define  BVAR_DETAIL_SAMPLER_H

#include <vector>
#include "butil/containers/linked_list.h"// LinkNode
#include "butil/scoped_lock.h"           // BAIDU_SCOPED_LOCK
#include "butil/logging.h"               // LOG()
#include "butil/containers/bounded_queue.h"// BoundedQueue
#include "butil/type_traits.h"           // is_same
#include "butil/time.h"                  // gettimeofday_us
#include "butil/class_name.h"

namespace bvar {
namespace detail {

template <typename T>
struct Sample {
    T data;
    int64_t time_us;

    Sample() : data(), time_us(0) {}
    Sample(const T& data2, int64_t time2) : data(data2), time_us(time2) {}  
};

// The base class for all samplers whose take_sample() are called periodically.
class Sampler : public butil::LinkNode<Sampler> {
public:
    Sampler();
        
    // This function will be called every second(approximately) in a
    // dedicated thread if schedule() is called.
    virtual void take_sample() = 0;

    // Register this sampler globally so that take_sample() will be called
    // periodically.
    void schedule();

    // Call this function instead of delete to destroy the sampler. Deletion
    // of the sampler may be delayed for seconds.
    void destroy();
        
protected:
    virtual ~Sampler();
    
friend class SamplerCollector;
    bool _used;
    // Sync destroy() and take_sample().
    butil::Mutex _mutex;
};

// Representing a non-existing operator so that we can test
// is_same<Op, VoidOp>::value to write code for different branches.
// The false branch should be removed by compiler at compile-time.
struct VoidOp {
    template <typename T>
    T operator()(const T&, const T&) const {
        CHECK(false) << "This function should never be called, abort";
        abort();
    }
};

// The sampler for reducer-alike variables.
// The R should have following methods:
//  - T reset();
//  - T get_value();
//  - Op op();
//  - InvOp inv_op();
template <typename R, typename T, typename Op, typename InvOp>
class ReducerSampler : public Sampler {
public:
    static const time_t MAX_SECONDS_LIMIT = 3600;

    explicit ReducerSampler(R* reducer)
        : _reducer(reducer)
        , _window_size(1) {
        
        // Invoked take_sample at begining so the value of the first second
        // would not be ignored
        take_sample();
    }
    ~ReducerSampler() {}

    void take_sample() override {
        // Make _q ready.
        // If _window_size is larger than what _q can hold, e.g. a larger
        // Window<> is created after running of sampler, make _q larger.
        if ((size_t)_window_size + 1 > _q.capacity()) {
            const size_t new_cap =
                std::max(_q.capacity() * 2, (size_t)_window_size + 1);
            const size_t memsize = sizeof(Sample<T>) * new_cap;
            void* mem = malloc(memsize);
            if (NULL == mem) {
                return;
            }
            butil::BoundedQueue<Sample<T> > new_q(
                mem, memsize, butil::OWNS_STORAGE);
            Sample<T> tmp;
            while (_q.pop(&tmp)) {
                new_q.push(tmp);
            }
            new_q.swap(_q);
        }

        Sample<T> latest;
        if (butil::is_same<InvOp, VoidOp>::value) {
            // The operator can't be inversed.
            // We reset the reducer and save the result as a sample.
            // Suming up samples gives the result within a window.
            // In this case, get_value() of _reducer gives wrong answer and
            // should not be called.
            latest.data = _reducer->reset();
        } else {
            // The operator can be inversed.
            // We save the result as a sample.
            // Inversed operation between latest and oldest sample within a
            // window gives result.
            // get_value() of _reducer can still be called.
            latest.data = _reducer->get_value();
        }
        latest.time_us = butil::gettimeofday_us();
        _q.elim_push(latest);
    }

    bool get_value(time_t window_size, Sample<T>* result) {
        if (window_size <= 0) {
            LOG(FATAL) << "Invalid window_size=" << window_size;
            return false;
        }
        BAIDU_SCOPED_LOCK(_mutex);
        if (_q.size() <= 1UL) {
            // We need more samples to get reasonable result.
            return false;
        }
        Sample<T>* oldest = _q.bottom(window_size);
        if (NULL == oldest) {
            oldest = _q.top();
        }
        Sample<T>* latest = _q.bottom();
        DCHECK(latest != oldest);
        if (butil::is_same<InvOp, VoidOp>::value) {
            // No inverse op. Sum up all samples within the window.
            result->data = latest->data;
            for (int i = 1; true; ++i) {
                Sample<T>* e = _q.bottom(i);
                if (e == oldest) {
                    break;
                }
                _reducer->op()(result->data, e->data);
            }
        } else {
            // Diff the latest and oldest sample within the window.
            result->data = latest->data;
            _reducer->inv_op()(result->data, oldest->data);
        }
        result->time_us = latest->time_us - oldest->time_us;
        return true;
    }

    // Change the time window which can only go larger.
    int set_window_size(time_t window_size) {
        if (window_size <= 0 || window_size > MAX_SECONDS_LIMIT) {
            LOG(ERROR) << "Invalid window_size=" << window_size;
            return -1;
        }
        BAIDU_SCOPED_LOCK(_mutex);
        if (window_size > _window_size) {
            _window_size = window_size;
        }
        return 0;
    }

    void get_samples(std::vector<T> *samples, time_t window_size) {
        if (window_size <= 0) {
            LOG(FATAL) << "Invalid window_size=" << window_size;
            return;
        }
        BAIDU_SCOPED_LOCK(_mutex);
        if (_q.size() <= 1) {
            // We need more samples to get reasonable result.
            return;
        }
        Sample<T>* oldest = _q.bottom(window_size);
        if (NULL == oldest) {
            oldest = _q.top();
        }
        for (int i = 1; true; ++i) {
            Sample<T>* e = _q.bottom(i);
            if (e == oldest) {
                break;
            }
            samples->push_back(e->data);
        }
    }

private:
    R* _reducer;
    time_t _window_size;
    butil::BoundedQueue<Sample<T> > _q;
};

}  // namespace detail
}  // namespace bvar

#endif  // BVAR_DETAIL_SAMPLER_H

Coverage Report

Created: 2025-08-05 06:45

Line	Count	Source (jump to first uncovered line)
1		// Licensed to the Apache Software Foundation (ASF) under one
2		// or more contributor license agreements. See the NOTICE file
3		// distributed with this work for additional information
4		// regarding copyright ownership. The ASF licenses this file
5		// to you under the Apache License, Version 2.0 (the
6		// "License"); you may not use this file except in compliance
7		// with the License. You may obtain a copy of the License at
8		//
9		// http://www.apache.org/licenses/LICENSE-2.0
10		//
11		// Unless required by applicable law or agreed to in writing,
12		// software distributed under the License is distributed on an
13		// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14		// KIND, either express or implied. See the License for the
15		// specific language governing permissions and limitations
16		// under the License.
17
18		// Date: Tue Jul 28 18:15:57 CST 2015
19
20		#ifndef BVAR_DETAIL_SAMPLER_H
21		#define BVAR_DETAIL_SAMPLER_H
22
23		#include <vector>
24		#include "butil/containers/linked_list.h"// LinkNode
25		#include "butil/scoped_lock.h" // BAIDU_SCOPED_LOCK
26		#include "butil/logging.h" // LOG()
27		#include "butil/containers/bounded_queue.h"// BoundedQueue
28		#include "butil/type_traits.h" // is_same
29		#include "butil/time.h" // gettimeofday_us
30		#include "butil/class_name.h"
31
32		namespace bvar {
33		namespace detail {
34
35		template <typename T>
36		struct Sample {
37		T data;
38		int64_t time_us;
39
40	0	Sample() : data(), time_us(0) {} Unexecuted instantiation: bvar::detail::Sample<bvar::detail::PercentileSamples<254ul> >::Sample() Unexecuted instantiation: bvar::detail::Sample<bvar::Stat>::Sample() Unexecuted instantiation: bvar::detail::Sample<double>::Sample() Unexecuted instantiation: bvar::detail::Sample<unsigned long>::Sample() Unexecuted instantiation: bvar::detail::Sample<int>::Sample() Unexecuted instantiation: bvar::detail::Sample<long>::Sample()
41		Sample(const T& data2, int64_t time2) : data(data2), time_us(time2) {}
42		};
43
44		// The base class for all samplers whose take_sample() are called periodically.
45		class Sampler : public butil::LinkNode<Sampler> {
46		public:
47		Sampler();
48
49		// This function will be called every second(approximately) in a
50		// dedicated thread if schedule() is called.
51		virtual void take_sample() = 0;
52
53		// Register this sampler globally so that take_sample() will be called
54		// periodically.
55		void schedule();
56
57		// Call this function instead of delete to destroy the sampler. Deletion
58		// of the sampler may be delayed for seconds.
59		void destroy();
60
61		protected:
62		virtual ~Sampler();
63
64		friend class SamplerCollector;
65		bool _used;
66		// Sync destroy() and take_sample().
67		butil::Mutex _mutex;
68		};
69
70		// Representing a non-existing operator so that we can test
71		// is_same<Op, VoidOp>::value to write code for different branches.
72		// The false branch should be removed by compiler at compile-time.
73		struct VoidOp {
74		template <typename T>
75	0	T operator()(const T&, const T&) const {
76	0	CHECK(false) << "This function should never be called, abort";
77	0	abort();
78	0	} Unexecuted instantiation: long bvar::detail::VoidOp::operator()<long>(long const&, long const&) const Unexecuted instantiation: bvar::detail::PercentileSamples<254ul> bvar::detail::VoidOp::operator()<bvar::detail::PercentileSamples<254ul> >(bvar::detail::PercentileSamples<254ul> const&, bvar::detail::PercentileSamples<254ul> const&) const
79		};
80
81		// The sampler for reducer-alike variables.
82		// The R should have following methods:
83		// - T reset();
84		// - T get_value();
85		// - Op op();
86		// - InvOp inv_op();
87		template <typename R, typename T, typename Op, typename InvOp>
88		class ReducerSampler : public Sampler {
89		public:
90		static const time_t MAX_SECONDS_LIMIT = 3600;
91
92		explicit ReducerSampler(R* reducer)
93	0	: _reducer(reducer)
94	0	, _window_size(1) {
95
96		// Invoked take_sample at begining so the value of the first second
97		// would not be ignored
98	0	take_sample();
99	0	} Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<double>, double, bvar::detail::AddTo<double>, bvar::detail::MinusFrom<double> >::ReducerSampler(bvar::PassiveStatus<double>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<unsigned long>, unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >::ReducerSampler(bvar::PassiveStatus<unsigned long>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >, int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >::ReducerSampler(bvar::Reducer<int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >, long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >::ReducerSampler(bvar::Reducer<long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<long>, long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >::ReducerSampler(bvar::PassiveStatus<long>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::IntRecorder, bvar::Stat, bvar::IntRecorder::AddStat, bvar::IntRecorder::MinusStat>::ReducerSampler(bvar::IntRecorder) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>, long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>::ReducerSampler(bvar::Reducer<long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::detail::Percentile, bvar::detail::PercentileSamples<254ul>, bvar::detail::Percentile::AddPercentileSamples, bvar::detail::VoidOp>::ReducerSampler(bvar::detail::Percentile) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >, unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >::ReducerSampler(bvar::Reducer<unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >*)
100	0	~ReducerSampler() {} Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<double>, double, bvar::detail::AddTo<double>, bvar::detail::MinusFrom<double> >::~ReducerSampler() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<unsigned long>, unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >::~ReducerSampler() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >, int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >::~ReducerSampler() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >, long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >::~ReducerSampler() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<long>, long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >::~ReducerSampler() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::IntRecorder, bvar::Stat, bvar::IntRecorder::AddStat, bvar::IntRecorder::MinusStat>::~ReducerSampler() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>, long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>::~ReducerSampler() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::detail::Percentile, bvar::detail::PercentileSamples<254ul>, bvar::detail::Percentile::AddPercentileSamples, bvar::detail::VoidOp>::~ReducerSampler() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >, unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >::~ReducerSampler()
101
102	0	void take_sample() override {
103		// Make _q ready.
104		// If _window_size is larger than what _q can hold, e.g. a larger
105		// Window<> is created after running of sampler, make _q larger.
106	0	if ((size_t)_window_size + 1 > _q.capacity()) {
107	0	const size_t new_cap =
108	0	std::max(_q.capacity() * 2, (size_t)_window_size + 1);
109	0	const size_t memsize = sizeof(Sample<T>) * new_cap;
110	0	void* mem = malloc(memsize);
111	0	if (NULL == mem) {
112	0	return;
113	0	}
114	0	butil::BoundedQueue<Sample<T> > new_q(
115	0	mem, memsize, butil::OWNS_STORAGE);
116	0	Sample<T> tmp;
117	0	while (_q.pop(&tmp)) {
118	0	new_q.push(tmp);
119	0	}
120	0	new_q.swap(_q);
121	0	}
122
123	0	Sample<T> latest;
124	0	if (butil::is_same<InvOp, VoidOp>::value) {
125		// The operator can't be inversed.
126		// We reset the reducer and save the result as a sample.
127		// Suming up samples gives the result within a window.
128		// In this case, get_value() of _reducer gives wrong answer and
129		// should not be called.
130	0	latest.data = _reducer->reset();
131	0	} else {
132		// The operator can be inversed.
133		// We save the result as a sample.
134		// Inversed operation between latest and oldest sample within a
135		// window gives result.
136		// get_value() of _reducer can still be called.
137	0	latest.data = _reducer->get_value();
138	0	}
139	0	latest.time_us = butil::gettimeofday_us();
140	0	_q.elim_push(latest);
141	0	} Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::IntRecorder, bvar::Stat, bvar::IntRecorder::AddStat, bvar::IntRecorder::MinusStat>::take_sample() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::detail::Percentile, bvar::detail::PercentileSamples<254ul>, bvar::detail::Percentile::AddPercentileSamples, bvar::detail::VoidOp>::take_sample() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<double>, double, bvar::detail::AddTo<double>, bvar::detail::MinusFrom<double> >::take_sample() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<unsigned long>, unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >::take_sample() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >, int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >::take_sample() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >, long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >::take_sample() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<long>, long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >::take_sample() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>, long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>::take_sample() Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >, unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >::take_sample()
142
143	0	bool get_value(time_t window_size, Sample<T>* result) {
144	0	if (window_size <= 0) {
145	0	LOG(FATAL) << "Invalid window_size=" << window_size;
146	0	return false;
147	0	}
148	0	BAIDU_SCOPED_LOCK(_mutex);
149	0	if (_q.size() <= 1UL) {
150		// We need more samples to get reasonable result.
151	0	return false;
152	0	}
153	0	Sample<T>* oldest = _q.bottom(window_size);
154	0	if (NULL == oldest) {
155	0	oldest = _q.top();
156	0	}
157	0	Sample<T>* latest = _q.bottom();
158	0	DCHECK(latest != oldest);
159	0	if (butil::is_same<InvOp, VoidOp>::value) {
160		// No inverse op. Sum up all samples within the window.
161	0	result->data = latest->data;
162	0	for (int i = 1; true; ++i) {
163	0	Sample<T>* e = _q.bottom(i);
164	0	if (e == oldest) {
165	0	break;
166	0	}
167	0	_reducer->op()(result->data, e->data);
168	0	}
169	0	} else {
170		// Diff the latest and oldest sample within the window.
171	0	result->data = latest->data;
172	0	_reducer->inv_op()(result->data, oldest->data);
173	0	}
174	0	result->time_us = latest->time_us - oldest->time_us;
175	0	return true;
176	0	} Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::IntRecorder, bvar::Stat, bvar::IntRecorder::AddStat, bvar::IntRecorder::MinusStat>::get_value(long, bvar::detail::Sample<bvar::Stat>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>, long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>::get_value(long, bvar::detail::Sample<long>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::detail::Percentile, bvar::detail::PercentileSamples<254ul>, bvar::detail::Percentile::AddPercentileSamples, bvar::detail::VoidOp>::get_value(long, bvar::detail::Sample<bvar::detail::PercentileSamples<254ul> >) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<double>, double, bvar::detail::AddTo<double>, bvar::detail::MinusFrom<double> >::get_value(long, bvar::detail::Sample<double>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<unsigned long>, unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >::get_value(long, bvar::detail::Sample<unsigned long>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >, int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >::get_value(long, bvar::detail::Sample<int>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >, long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >::get_value(long, bvar::detail::Sample<long>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<long>, long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >::get_value(long, bvar::detail::Sample<long>) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >, unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >::get_value(long, bvar::detail::Sample<unsigned long>*)
177
178		// Change the time window which can only go larger.
179	0	int set_window_size(time_t window_size) {
180	0	if (window_size <= 0 \|\| window_size > MAX_SECONDS_LIMIT) {
181	0	LOG(ERROR) << "Invalid window_size=" << window_size;
182	0	return -1;
183	0	}
184	0	BAIDU_SCOPED_LOCK(_mutex);
185	0	if (window_size > _window_size) {
186	0	_window_size = window_size;
187	0	}
188	0	return 0;
189	0	} Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<double>, double, bvar::detail::AddTo<double>, bvar::detail::MinusFrom<double> >::set_window_size(long) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<unsigned long>, unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >::set_window_size(long) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >, int, bvar::detail::AddTo<int>, bvar::detail::MinusFrom<int> >::set_window_size(long) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >, long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >::set_window_size(long) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::PassiveStatus<long>, long, bvar::detail::AddTo<long>, bvar::detail::MinusFrom<long> >::set_window_size(long) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::IntRecorder, bvar::Stat, bvar::IntRecorder::AddStat, bvar::IntRecorder::MinusStat>::set_window_size(long) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>, long, bvar::detail::MaxTo<long>, bvar::detail::VoidOp>::set_window_size(long) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::detail::Percentile, bvar::detail::PercentileSamples<254ul>, bvar::detail::Percentile::AddPercentileSamples, bvar::detail::VoidOp>::set_window_size(long) Unexecuted instantiation: bvar::detail::ReducerSampler<bvar::Reducer<unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >, unsigned long, bvar::detail::AddTo<unsigned long>, bvar::detail::MinusFrom<unsigned long> >::set_window_size(long)
190
191	0	void get_samples(std::vector<T> *samples, time_t window_size) {
192	0	if (window_size <= 0) {
193	0	LOG(FATAL) << "Invalid window_size=" << window_size;
194	0	return;
195	0	}
196	0	BAIDU_SCOPED_LOCK(_mutex);
197	0	if (_q.size() <= 1) {
198		// We need more samples to get reasonable result.
199	0	return;
200	0	}
201	0	Sample<T>* oldest = _q.bottom(window_size);
202	0	if (NULL == oldest) {
203	0	oldest = _q.top();
204	0	}
205	0	for (int i = 1; true; ++i) {
206	0	Sample<T>* e = _q.bottom(i);
207	0	if (e == oldest) {
208	0	break;
209	0	}
210	0	samples->push_back(e->data);
211	0	}
212	0	}
213
214		private:
215		R* _reducer;
216		time_t _window_size;
217		butil::BoundedQueue<Sample<T> > _q;
218		};
219
220		} // namespace detail
221		} // namespace bvar
222
223		#endif // BVAR_DETAIL_SAMPLER_H