mutilate/LogHistogramSampler.h
2013-01-30 19:46:39 -08:00

96 lines
1.7 KiB
C++

/* -*- c++ -*- */
#ifndef LOGHISTOGRAMSAMPLER_H
#define LOGHISTOGRAMSAMPLER_H
#include <assert.h>
#include <inttypes.h>
#include <math.h>
#include <vector>
#include "Operation.h"
#define _POW 1.1
class LogHistogramSampler {
public:
std::vector<uint64_t> bins;
double sum;
LogHistogramSampler() = delete;
LogHistogramSampler(int _bins) : sum(0.0) {
assert(_bins > 0);
bins.resize(_bins + 1, 0);
}
void sample(const Operation &op) {
sample(op.time());
}
void sample(double s) {
assert(s >= 0);
size_t bin = log(s)/log(_POW);
sum += s;
// I("%f", sum);
if ((int64_t) bin < 0) {
bin = 0;
} else if (bin >= bins.size()) {
bin = bins.size() - 1;
}
bins[bin]++;
}
double average() {
// I("%f %d", sum, total());
return sum / total();
}
double minimum() {
for (size_t i = 0; i < bins.size(); i++)
if (bins[i] > 0) return pow(_POW, (double) i + 0.5);
DIE("Not implemented");
}
double get_nth(double nth) {
uint64_t count = total();
uint64_t n = 0;
double target = count * nth/100;
for (size_t i = 0; i < bins.size(); i++) {
n += bins[i];
if (n > target) { // The nth is inside bins[i].
double left = target - (n - bins[i]);
return pow(_POW, (double) i) +
left / bins[i] * (pow(_POW, (double) (i+1)) - pow(_POW, (double) i));
}
}
return pow(_POW, bins.size());
}
uint64_t total() {
uint64_t sum = 0.0;
for (auto i: bins) sum += i;
return sum;
}
void accumulate(const LogHistogramSampler &h) {
assert(bins.size() == h.bins.size());
for (size_t i = 0; i < bins.size(); i++) bins[i] += h.bins[i];
sum += h.sum;
}
};
#endif // LOGHISTOGRAMSAMPLER_H