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#include "histogram_collector.h"
#include "atomics_array.h"
#include <util/generic/algorithm.h>
#include <util/generic/vector.h>
#include <util/generic/yexception.h>
#include <util/generic/ylimits.h>
namespace NMonitoring {
///////////////////////////////////////////////////////////////////////////
// TExponentialHistogramCollector
///////////////////////////////////////////////////////////////////////////
class TExponentialHistogramCollector: public IHistogramCollector {
public:
TExponentialHistogramCollector(ui32 bucketsCount, double base, double scale)
: Values_(bucketsCount)
, Base_(base)
, Scale_(scale)
, MinValue_(scale)
, MaxValue_(scale * std::pow(base, bucketsCount - 2))
, LogOfBase_(std::log(base))
{
}
void Collect(double value, ui64 count) override {
ui32 index = Max<ui32>();
if (value <= MinValue_) {
index = 0;
} else if (value > MaxValue_) {
index = Values_.Size() - 1;
} else {
double logBase = std::log(value / Scale_) / LogOfBase_;
index = static_cast<ui32>(std::ceil(logBase));
}
Values_.Add(index, count);
}
void Reset() override {
Values_.Reset();
}
IHistogramSnapshotPtr Snapshot() const override {
return new TExponentialHistogramSnapshot(Base_, Scale_, Values_.Copy());
}
private:
TAtomicsArray Values_;
double Base_;
double Scale_;
TBucketBound MinValue_;
TBucketBound MaxValue_;
double LogOfBase_;
};
IHistogramCollectorPtr ExponentialHistogram(
ui32 bucketsCount, double base, double scale)
{
Y_ENSURE(bucketsCount >= 2,
"exponential histogram must contain at least two buckets");
Y_ENSURE(bucketsCount <= HISTOGRAM_MAX_BUCKETS_COUNT,
"buckets count must be <=" << HISTOGRAM_MAX_BUCKETS_COUNT
<< ", but got: " << bucketsCount);
Y_ENSURE(base > 1.0, "base must be > 1.0, got: " << base);
Y_ENSURE(scale >= 1.0, "scale must be >= 1.0, got: " << scale);
return MakeHolder<TExponentialHistogramCollector>(bucketsCount, base, scale);
}
}
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