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Remove mean/stddev computation in C++

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It's broken (also in Go), will fix in the following days.
This commit is contained in:
Francesco Mazzoli
2023-07-19 11:48:38 +00:00
parent dce2961d7f
commit 6aa670b481
1 changed files with 1 additions and 48 deletions
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cpp/core/Timings.hpp
+1 -48
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@@ -19,23 +19,14 @@ private:
uint64_t _firstUpperBound;
double _growthDivUpperBound;
// changing stuff
std::array<std::atomic<uint64_t>, BINS> _hist;
// mean/variance
std::mutex _mu;
int64_t _count;
int64_t _mean;
int64_t _m2;
public:
Timings(Duration firstUpperBound, double growth) :
_growth(growth),
_invLogGrowth(1.0/log(growth)),
_firstUpperBound(firstUpperBound.ns),
_growthDivUpperBound(growth / (double)firstUpperBound.ns),
_count(0),
_mean(0),
_m2(0)
_growthDivUpperBound(growth / (double)firstUpperBound.ns)
{
if (firstUpperBound < 1) {
throw EGGS_EXCEPTION("non-positive first upper bound %s", firstUpperBound);
@@ -48,15 +39,6 @@ public:
}
}
Duration mean() const {
return Duration(_mean);
}
Duration stddev() const {
if (_count == 0) { return 0; }
return Duration(sqrt(_m2 / _count));
}
void add(Duration d) {
int64_t inanos = d.ns;
if (inanos < 0) { return; }
@@ -66,36 +48,11 @@ public:
int bin = std::min<int>(BINS, std::max<int>(0, log((double)nanos * _growthDivUpperBound) * _invLogGrowth));
_hist[bin]++;
}
// mean/variance
{
std::lock_guard<std::mutex> guard(_mu); // should be almost always uncontended.
_count++;
int64_t delta = inanos - _mean;
_mean += delta / _count;
int64_t delta2 = inanos - _mean;
_m2 += delta * delta2;
}
}
void toStats(const std::string& prefix, std::vector<Stat>& stats) const {
static_assert(std::endian::native == std::endian::little);
auto now = eggsNow();
{
auto& meanStat = stats.emplace_back();
meanStat.time = now;
meanStat.name = BincodeBytes(prefix + ".mean");
uint64_t x = mean().ns;
meanStat.value.els.resize(sizeof(x));
memcpy(meanStat.value.els.data(), &x, sizeof(x));
}
{
auto& stddevStat = stats.emplace_back();
stddevStat.time = now;
stddevStat.name = BincodeBytes(prefix + ".stddev");
uint64_t x = stddev().ns;
stddevStat.value.els.resize(sizeof(x));
memcpy(stddevStat.value.els.data(), &x, sizeof(x));
}
{
auto& histStat = stats.emplace_back();
histStat.time = now;
@@ -117,9 +74,5 @@ public:
for (int i = 0; i < BINS; i++) {
_hist[i].store(0);
}
std::lock_guard<std::mutex> guard(_mu);
_count = 0;
_mean = 0;
_m2 = 0;
}
};