in util/Stats.cpp [50:75]
void Counter::record(int64_t v) {
int64_t newCount = ++count_;
sum_ += v;
if (newCount == 1) {
realMin_ = min_ = max_ = v;
}
// don't count 0s in the min - makes for a slightly more interesting min
// in most cases
if (v && ((min_ == 0) || (v < min_))) {
min_ = v;
}
// real min (can be 0):
if (v < realMin_ ) {
realMin_ = v;
}
if (v > max_) {
max_ = v;
}
int64_t v2 = 0;
if (v > INT32_MAX || v < INT32_MIN) {
LOG(WARNING) << "v too big for stddev " << v;
} else {
v2 = v * v;
}
sumOfSquares_ += v2; // atomic_add(sumOfSquares_, v2);
}