diff --git a/src/bench/bench.cpp b/src/bench/bench.cpp index 6ee3cdc27..227546a7a 100644 --- a/src/bench/bench.cpp +++ b/src/bench/bench.cpp @@ -5,6 +5,7 @@ #include "bench.h" #include +#include #include using namespace benchmark; @@ -25,7 +26,7 @@ BenchRunner::BenchRunner(std::string name, BenchFunction func) void BenchRunner::RunAll(double elapsedTimeForOne) { - std::cout << "Benchmark" << "," << "count" << "," << "min" << "," << "max" << "," << "average" << "\n"; + std::cout << "#Benchmark" << "," << "count" << "," << "min" << "," << "max" << "," << "average" << "\n"; for (std::map::iterator it = benchmarks.begin(); it != benchmarks.end(); ++it) { @@ -38,22 +39,34 @@ BenchRunner::RunAll(double elapsedTimeForOne) bool State::KeepRunning() { + if (count & countMask) { + ++count; + return true; + } double now; if (count == 0) { - beginTime = now = gettimedouble(); + lastTime = beginTime = now = gettimedouble(); } else { - // timeCheckCount is used to avoid calling gettime most of the time, - // so benchmarks that run very quickly get consistent results. - if ((count+1)%timeCheckCount != 0) { - ++count; - return true; // keep going - } now = gettimedouble(); - double elapsedOne = (now - lastTime)/timeCheckCount; + double elapsed = now - lastTime; + double elapsedOne = elapsed * countMaskInv; if (elapsedOne < minTime) minTime = elapsedOne; if (elapsedOne > maxTime) maxTime = elapsedOne; - if (elapsedOne*timeCheckCount < maxElapsed/16) timeCheckCount *= 2; + if (elapsed*128 < maxElapsed) { + // If the execution was much too fast (1/128th of maxElapsed), increase the count mask by 8x and restart timing. + // The restart avoids including the overhead of this code in the measurement. + countMask = ((countMask<<3)|7) & ((1LL<<60)-1); + countMaskInv = 1./(countMask+1); + count = 0; + minTime = std::numeric_limits::max(); + maxTime = std::numeric_limits::min(); + return true; + } + if (elapsed*16 < maxElapsed) { + countMask = ((countMask<<1)|1) & ((1LL<<60)-1); + countMaskInv = 1./(countMask+1); + } } lastTime = now; ++count; @@ -64,7 +77,7 @@ bool State::KeepRunning() // Output results double average = (now-beginTime)/count; - std::cout << name << "," << count << "," << minTime << "," << maxTime << "," << average << "\n"; + std::cout << std::fixed << std::setprecision(15) << name << "," << count << "," << minTime << "," << maxTime << "," << average << "\n"; return false; } diff --git a/src/bench/bench.h b/src/bench/bench.h index 5ce13c642..f13b145aa 100644 --- a/src/bench/bench.h +++ b/src/bench/bench.h @@ -40,14 +40,15 @@ namespace benchmark { std::string name; double maxElapsed; double beginTime; - double lastTime, minTime, maxTime; + double lastTime, minTime, maxTime, countMaskInv; int64_t count; - int64_t timeCheckCount; + int64_t countMask; public: State(std::string _name, double _maxElapsed) : name(_name), maxElapsed(_maxElapsed), count(0) { minTime = std::numeric_limits::max(); maxTime = std::numeric_limits::min(); - timeCheckCount = 1; + countMask = 1; + countMaskInv = 1./(countMask + 1); } bool KeepRunning(); };