How to find O of threads ?

Howdy , ...

I guess this is really lame question for this forum (it must by to obvieus since i even didn't found this in the FAQ ) .

Any way ...

When working with threads (mostly in Java but some times with pthreads) i noticed that same thread can take diffrent time (on idle machine ) and when there are n threads this dosn't mean that it will take n * k {k in setZ+) but more as n * p^k .

I tried to find a quick answer and found the next :
Head of the software eng. department :
The best way to find why is to read the Native code behind the OS that implement this (This is the nicest RTFM i got in my life ) .

2'rd year software development student from Technion :
Perheps there is a logaritmic or expentional function for some n but then it become liner so to test it you should use really large quantetis.

Since both answers didn't sutisfy me i come here ...

so how can i calculate and find the assymtotic function for a given set of threads .
since even if each thread is O(1) the can take diffrent times.

I'm searching for some thing as :
T(n) = h(thread) + O(something)

None of that is making any sense.
Forget trying to get mathematical and just come out and ask a basic one line English question.

This may hep.

http://www.eternallyconfuzzled.com/a..._art_bigo.aspx

An assymptotic bound isn't going to explain the difference in run times for a particular implementation. It could be any number of things, from waiting on shared resources to initialization, to race conditions in your program.