plf::nanotimer

A simple C++ 03/11/etc timer class for ~microsecond-precision cross-platform benchmarking. The implementation is as limited and simple as possible to afford the lowest amount of overhead.

Use as follows:

#include "plf_nanotimer.hpp"


plf::nanotimer timer;


timer.start()

// Do something here

double results = timer.get_elapsed_ns();
std::cout << "Timing: " << results << " nanoseconds." << std::endl;


timer.start(); // "start" has the same semantics as "restart".

// Do something else

results = timer.get_elapsed_ms();
std::cout << "Timing: " << results << " milliseconds." << std::endl;


timer.start()

plf::microsecond_delay(15); // Delay program for 15 microseconds

results = timer.get_elapsed_us();
std::cout << "Timing: " << results << " microseconds." << std::endl;

Timer member functions:

void start(): start or restart timer

double get_elapsed_ns(): get elapsed time in nanoseconds

double get_elapsed_us(): get elapsed time in microseconds

double get_elapsed_ms(): get elapsed time in milliseconds

Non-member functions:

void plf::millisecond_delay(double x): delay the program until x milliseconds have passed

void plf::microsecond_delay(double x): delay the program until x microseconds have passed

void plf::nanosecond_delay(double x): delay the program until x nanoseconds have passed

Timer 'pausing':

I determined that a 'pause'-style function would add too much complexity to the class for simple benchmarking, which in turn might interfere with performance analysis, so if you need a 'pause' function do something like this:

plf::nanotimer timer;


timer.start()
// Do something here
double results = timer.get_elapsed_ns();

// Do something else - timer 'paused'

timer.start()

// Do stuff

results += timer.get_elapsed_ns();

std::cout << "Timing: " << results << " nanoseconds." << std::endl;

Why not use the CPU's cycle counter (RDTSC) directly?

See https://stackoverflow.com/questions/13772567/how-to-get-the-cpu-cycle-count-in-x86-64-from-c; note the various issues mentioned in the responses there.