1 //===-- Metric.cpp ----------------------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "Metric.h" 11 #include "MemoryGauge.h" 12 #include <cmath> 13 14 using namespace lldb_perf; 15 16 template <class T> 17 Metric<T>::Metric () : Metric ("") 18 { 19 } 20 21 template <class T> 22 Metric<T>::Metric (const char* n, const char* d) : 23 m_name(n ? n : ""), 24 m_description(d ? d : ""), 25 m_dataset () 26 { 27 } 28 29 template <class T> 30 void 31 Metric<T>::Append (T v) 32 { 33 m_dataset.push_back(v); 34 } 35 36 template <class T> 37 size_t 38 Metric<T>::GetCount () const 39 { 40 return m_dataset.size(); 41 } 42 43 template <class T> 44 T 45 Metric<T>::GetSum () const 46 { 47 T sum = 0; 48 for (auto v : m_dataset) 49 sum += v; 50 return sum; 51 } 52 53 template <class T> 54 T 55 Metric<T>::GetAverage () const 56 { 57 return GetSum()/GetCount(); 58 } 59 60 61 // Knuth's algorithm for stddev - massive cancellation resistant 62 template <class T> 63 T 64 Metric<T>::GetStandardDeviation (StandardDeviationMode mode) const 65 { 66 size_t n = 0; 67 T mean = 0; 68 T M2 = 0; 69 for (auto x : m_dataset) 70 { 71 n = n + 1; 72 T delta = x - mean; 73 mean = mean + delta/n; 74 M2 = M2+delta*(x-mean); 75 } 76 T variance; 77 if (mode == StandardDeviationMode::ePopulation || n == 1) 78 variance = M2 / n; 79 else 80 variance = M2 / (n - 1); 81 return sqrt(variance); 82 } 83 84 template class lldb_perf::Metric<double>; 85 template class lldb_perf::Metric<MemoryStats>; 86
