C GetTickCount (windows function) to Time (nanoseconds)

Question

Hello guys, I'm testing one code provided from my colleague and I need to measure the time of execution of one routine than performs a context switch (of threads).

What's the best choice to measure the time? I know that is available High Resolution Timers like,

QueryPerformanceCounter
QueryPerformanceFrequency

but how can I translate using that timers to miliseconds or nanoseconds?

Answer 1

As the operation than i am executing is in order of 500 nanos, and the timers doens't have precision, what i made was,

i saved actual time with GetTickCount() - (Uses precision of ~ 12milis) and performs the execution of a route N_TIMES (Number of times than routine executed) than remains until i press something on console.

Calculate the time again, and make the difference dividing by N_TIMES, something like that:

int static counter;

void routine() { // Operations here.. counter++; }

int main(){
start <- GetTickCount(); handle <- createThread(....., routine,...);
resumeThread(handle);

getchar();

WaitForSingleObject(handle, INFINITE);

Elapsed = (GetTickCount() - start) * 1000000.0) / counter; printf("Nanos: %d", elapsed); }

:)