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Separated out code into separate files, used common substream_summary.
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libconfluo/confluo/container/sketch/substream_summary.h
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| #ifndef CONFLUO_CONTAINER_SKETCH_SUBSTREAM_SUMMARY_H | ||
| #define CONFLUO_CONTAINER_SKETCH_SUBSTREAM_SUMMARY_H | ||
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| #include <vector> | ||
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| #include "atomic.h" | ||
| #include "count_sketch.h" | ||
| #include "hash_manager.h" | ||
| #include "priority_queue.h" | ||
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| namespace confluo { | ||
| namespace sketch { | ||
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| template<typename T, typename counter_t = int64_t> | ||
| class substream_summary { | ||
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| public: | ||
| typedef atomic::type<counter_t> atomic_counter_t; | ||
| typedef std::vector<atomic::type<T>> atomic_vector_t; | ||
| typedef count_sketch<T, counter_t> sketch_t; | ||
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| substream_summary() = default; | ||
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| /** | ||
| * Constructor | ||
| * @param t depth (number of estimates) | ||
| * @param b width (number of buckets) | ||
| * @param k number of heavy hitters to track | ||
| * @param a heavy hitter threshold | ||
| * @param precise track exact heavy hitters | ||
| */ | ||
| substream_summary(size_t t, size_t b, size_t k, double a, bool precise = true) | ||
| : hh_threshold_(a), | ||
| num_hh_(k), | ||
| l2_squared_(), | ||
| sketch_(t, b), | ||
| heavy_hitters_(k), | ||
| hhs_precise_(), | ||
| hh_hash_(pairwise_indep_hash::generate_random()), | ||
| use_precise_hh_(precise) { | ||
| } | ||
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| substream_summary(const substream_summary& other) | ||
| : hh_threshold_(other.hh_threshold_), | ||
| num_hh_(other.num_hh_), | ||
| l2_squared_(atomic::load(&other.l2_squared_)), | ||
| sketch_(other.sketch_), | ||
| heavy_hitters_(other.heavy_hitters_.size()), | ||
| hhs_precise_(other.hhs_precise_), | ||
| hh_hash_(other.hh_hash_), | ||
| use_precise_hh_(other.use_precise_hh_) { | ||
| for (size_t i = 0; i < other.heavy_hitters_.size(); i++) { | ||
| atomic::store(&heavy_hitters_[i], atomic::load(&other.heavy_hitters_[i])); | ||
| } | ||
| } | ||
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| substream_summary& operator=(const substream_summary& other) { | ||
| hh_threshold_ = other.hh_threshold_; | ||
| num_hh_ = other.num_hh_; | ||
| l2_squared_ = atomic::load(&other.l2_squared_); | ||
| sketch_ = other.sketch_; | ||
| heavy_hitters_ = atomic_vector_t(other.heavy_hitters_.size()); | ||
| hhs_precise_ = other.hhs_precise_; | ||
| hh_hash_ = other.hh_hash_; | ||
| use_precise_hh_ = other.use_precise_hh_; | ||
| for (size_t i = 0; i < other.heavy_hitters_.size(); i++) { | ||
| atomic::store(&heavy_hitters_[i], atomic::load(&other.heavy_hitters_[i])); | ||
| } | ||
| return *this; | ||
| } | ||
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| void update(T key) { | ||
| counter_t old_count = sketch_.update_and_estimate(key); | ||
| counter_t update = l2_squared_update(old_count); | ||
| counter_t old_l2_sq = atomic::faa(&l2_squared_, update); | ||
| double new_l2 = std::sqrt(old_l2_sq + update); | ||
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| if (use_precise_hh_) { | ||
| this->update_hh_pq(key, old_count + 1, new_l2); | ||
| } else { | ||
| this->update_hh_approx(key, old_count + 1, new_l2); | ||
| } | ||
| } | ||
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| /** | ||
| * Estimate count | ||
| * @param key key | ||
| * @return estimated count | ||
| */ | ||
| counter_t estimate(T key) { | ||
| return sketch_.estimate(key); | ||
| } | ||
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| /** | ||
| * @return sketch | ||
| */ | ||
| sketch_t& get_sketch() { | ||
| return sketch_; | ||
| } | ||
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| atomic_vector_t& get_heavy_hitters() { | ||
| return heavy_hitters_; | ||
| } | ||
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| heavy_hitter_set<T, counter_t>& get_pq() { | ||
| return hhs_precise_; | ||
| } | ||
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| /** | ||
| * @return size of data structure in bytes | ||
| */ | ||
| size_t storage_size() { | ||
| size_t total_size = 0; | ||
| total_size += sketch_.storage_size(); | ||
| total_size += heavy_hitters_.size(); | ||
| return total_size; | ||
| } | ||
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| private: | ||
| /** | ||
| * Update heavy hitters priority queue | ||
| * @param key key | ||
| * @param count frequency count | ||
| * @param l2 current l2 norm | ||
| */ | ||
| void update_hh_pq(T key, counter_t count, double l2) { | ||
| if (count < hh_threshold_ * l2) { | ||
| return; | ||
| } | ||
| if (hhs_precise_.size() < num_hh_) { | ||
| hhs_precise_.remove_if_exists(key); | ||
| hhs_precise_.pushp(key, count); | ||
| } else { | ||
| T head = hhs_precise_.top().key_; | ||
| if (sketch_.estimate(head) < count) { | ||
| hhs_precise_.pop(); | ||
| hhs_precise_.remove_if_exists(key); | ||
| hhs_precise_.pushp(key, count); | ||
| } | ||
| } | ||
| } | ||
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| /** | ||
| * Update heavy hitters approximate DS | ||
| * @param key key | ||
| * @param count frequency count | ||
| * @param l2 current l2 norm | ||
| */ | ||
| void update_hh_approx(T key, counter_t count, double l2) { | ||
| if (count < hh_threshold_ * l2) { | ||
| return; | ||
| } | ||
| bool done = false; | ||
| while (!done) { | ||
| size_t idx = hh_hash_.apply<T>(key) % heavy_hitters_.size(); | ||
| T prev = atomic::load(&heavy_hitters_[idx]); | ||
| if (prev == key) | ||
| return; | ||
| counter_t prev_count = sketch_.estimate(prev); | ||
| done = (prev_count > count) ? true : atomic::strong::cas(&heavy_hitters_[idx], &prev, key); | ||
| } | ||
| } | ||
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| /** | ||
| * L_2^2 += (c_i + 1)^2 - (c_i)^2 | ||
| * @param old_count estimate of a count before an update | ||
| */ | ||
| static inline counter_t l2_squared_update(counter_t old_count) { | ||
| return 2 * old_count + 1; | ||
| } | ||
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| double hh_threshold_; // heavy hitter threshold | ||
| size_t num_hh_; // number of heavy hitters to track (k) | ||
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| atomic_counter_t l2_squared_; // L2 norm squared | ||
| sketch_t sketch_; | ||
| atomic_vector_t heavy_hitters_; | ||
| heavy_hitter_set<T, counter_t> hhs_precise_; | ||
| pairwise_indep_hash hh_hash_; | ||
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| bool use_precise_hh_; | ||
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| }; | ||
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| } | ||
| } | ||
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| #endif // CONFLUO_CONTAINER_SKETCH_SUBSTREAM_SUMMARY_H |
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