📅 2011-Apr-08 ⬩ ✍️ Ashwin Nanjappa ⬩ 🏷️ cpp, timer ⬩ 📚 Archive
Timers are useful to find the performance bottlenecks in code. If a timer resolution of 1ms is enough for your application, you can use the
clock function from
<ctime> as shown here.
However, if you need timers of a far higher resolution on Windows, a popular choice is to use the high-resolution performance counter API. All calls of this API rely on a
LARGE_INTEGER data type.
Use QueryPerformanceCounter to note down the begin and end times of your code:
#include <windows.h> LARGE_INTEGER beginTime; QueryPerformanceCounter( &beginTime ); // Code to measure ... LARGE_INTEGER endTime;QueryPerformanceCounter( &endTime );
Use QueryPerformanceFrequency to find the timer frequency. Use that to convert the time difference to seconds:
LARGE_INTEGER timerFreq; QueryPerformanceFrequency( &timerFreq );const double freq = 1.0f / timerFreq.QuadPart; const double timeSeconds = ( endTime.QuadPart - beginTime.QuadPart ) * freq;
A PerfTimer class that exposes this as simple
value() calls is available here.
Tried with: Visual C++ 2008