1 files changed, 59 insertions, 0 deletions
diff --git a/library/cpp/monlib/dynamic_counters/percentile/percentile.h b/library/cpp/monlib/dynamic_counters/percentile/percentile.h
new file mode 100644
index 0000000000..73c482bce9
--- /dev/null
+++ b/library/cpp/monlib/dynamic_counters/percentile/percentile.h
@@ -0,0 +1,59 @@
+#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 {
+    TAtomic Items[BUCKET_COUNT];
+    TAtomicBase Frame[FRAME_COUNT][BUCKET_COUNT];
+    size_t CurrentFrame;
+
+    TPercentileTracker()
+        : CurrentFrame(0)
+    {
+        for (size_t i = 0; i < BUCKET_COUNT; ++i) {
+            AtomicSet(Items[i], 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) {
+        AtomicIncrement(Items[Min((value + BUCKET_SIZE - 1) / BUCKET_SIZE, BUCKET_COUNT - 1)]);
+    }
+
+    // shift frame (call periodically)
+    void Update() {
+        TVector<TAtomicBase> totals(BUCKET_COUNT);
+        totals.resize(BUCKET_COUNT);
+        TAtomicBase total = 0;
+        for (size_t i = 0; i < BUCKET_COUNT; ++i) {
+            TAtomicBase item = AtomicGet(Items[i]);
+            TAtomicBase 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 = (TAtomicBase)(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