if you want to test a part of your code, and want to fill cache with random data, so you want that your code won''t be in cache, you have to read several MB from memory before each iteration of looptest ?

int FillCache()
{
	int tr=0;
	int mem = 1024*1024;
	int *dir = (int *)malloc(sizeof(int)*mem+4);

	for (int i=0;i<mem;i+=6)
	{
		tr += *(dir+i);
		tr -= *(dir+i+1);
		tr += *(dir+i+2);
		tr -= *(dir+i+3);
		tr += *(dir+i+4);
		tr -= *(dir+i+5);
	}

	free(dir);
	return tr;
}

// +,- and return are for vc not full-optimize it and remove the useless loop

This code will fill the cache ? And, if you want your code resident in cache, you must execute the code before do the looptest ? Thanks

um.... why would you EVER want your code to not be in the cache?

-me

To profile the worst case, when the code isn''t in cache.

ok, but IMHO that''s not the best way to go about profiling your code. the typical way to profile your code is to run it as the full game. the profiler them points our to you in which areas of your code the program spends the most time. from there you optimize the areas that are the bottlenecks, preferably by changing algorithms and only finally as optimizing the actual code. while profiling as you are talking about might tell you some interesting things about the code, it''s not really going to tell you anything interesting about how that code performs when it''s actually running in the context of your game.

search around for other profiling threads. there was a really nice, free profiler that you can download and use mentioned in another thread. the name escapes me, but i''d go that route rather than your route.

anyway, AFAIK, the cache is going to get emptied and refilled with your code as soon as you start running the code that follows your cache filling. so what you are trying to do (run the code entirely out of cache) has no hope of working. the processor will just dump your fake data in preference to the actual data that''s being processed.

-me

Thanks for your reply, I want to profile a library alone, not within a game, so I can''t profile all to see bottlenecks, what I want is to profile the functions that provide the library, and select the optimum methods and descarts the rest.

If I measure fillcache function, I execute fillcache inside the looptest, and later to the total time/clocks subtract the (fillcache_time*number_of_loops) will tell me an accurate result ?