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Measure execution cycles of a code..

I am now writing a code in C.
I want to measure execution speed of a code for as high resolution as possible.
I've tried to read PC timer (mc146818) datasheet, its registers can only give 1 second resolution.
Interrupt 1A can only gives 1/100 second resolution.
If it is possible, I want to get the result as a number of clock cycles.
Anybody can point me out about this?

Thanks,

alexo

If you program under windows, check the following functions:
QueryPerformanceCounter()
QueryPerformanceFrequency()

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alexo

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3rsrichard

I can suggest two possible solutions
1) If you can run your program on a machine using Windows NT you can use the Administrative Tools - Performance Monitor to get something related to what you want.

The problem with trying to use the hardware timers is that the answer you get will be based on a specific set of hardware. Another approach is to compile the code, get a listing, and count the number of instructions being executed. Or if you have a debugger which keeps track of the number of lines executed that would do it.

Zoppo

Hi wayud,

Have you tried 'clock'? It's resolution seems to be at least 20ms. Use it like this:

#include <time.h>

clock_t end, start = clock();
// do lengthy processing
end = clock();

hope that helps,

ZOPPO

Wyn

->If you program under windows, check the following functions:
QueryPerformanceCounter()
QueryPerformanceFrequency()
=================================
Fully agree.

jhance

Another approach is to run the instructions in question 10, 100, 1000, etc. times (whatever is needed to get a meaningful result with the timer available) and then scale the result.

wayud

ASKER

Thank you for all of you..
This is what I really need.
I'll try it now.