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#pragma once
#include "percentile_base.h"
namespace NMonitoring {
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Percentile tracker for monitoring
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
template <size_t BUCKET_SIZE, size_t BUCKET_COUNT, size_t FRAME_COUNT>
struct TPercentileTracker : public TPercentileBase {
std::atomic<size_t> Items[BUCKET_COUNT];
size_t Frame[FRAME_COUNT][BUCKET_COUNT];
size_t CurrentFrame;
TPercentileTracker()
: CurrentFrame(0)
{
for (size_t i = 0; i < BUCKET_COUNT; ++i) {
Items[i].store(0);
}
for (size_t frame = 0; frame < FRAME_COUNT; ++frame) {
for (size_t bucket = 0; bucket < BUCKET_COUNT; ++bucket) {
Frame[frame][bucket] = 0;
}
}
}
void Increment(size_t value) {
auto idx = Min((value + BUCKET_SIZE - 1) / BUCKET_SIZE, BUCKET_COUNT - 1);
Items[idx].fetch_add(1, std::memory_order_relaxed);
}
// shift frame (call periodically)
void Update() {
std::array<size_t, BUCKET_COUNT> totals;
size_t total = 0;
for (size_t i = 0; i < BUCKET_COUNT; ++i) {
size_t item = Items[i].load(std::memory_order_relaxed);
size_t prevItem = Frame[CurrentFrame][i];
Frame[CurrentFrame][i] = item;
total += item - prevItem;
totals[i] = total;
}
for (size_t i = 0; i < Percentiles.size(); ++i) {
TPercentile &percentile = Percentiles[i];
auto threshold = (size_t)(percentile.first * (float)total);
threshold = Min(threshold, total);
auto it = LowerBound(totals.begin(), totals.end(), threshold);
size_t index = it - totals.begin();
(*percentile.second) = index * BUCKET_SIZE;
}
CurrentFrame = (CurrentFrame + 1) % FRAME_COUNT;
}
};
} // NMonitoring
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