Re: 2nd Attempt : How can I count the actual number of operations performed in a program
junaidnaseer wrote:
@ Mlimber
Shouldn't you be counting on the compiled code? And more to
the point, shouldn't you be using some existing profiling tool to make
your measurements?
The problem is to count operations on runtime , not on compilation or
after linking !
If some profiler or debugger can do this then please guide this poor
soul .
My point was that you don't know what the compiler is doing to your
code. It might optimize some operation that you *think* is expensive.
For instance, on one processor I have worked on, the pipeline has to be
flushed for a branch instruction, which meant 5 wasted cycles, but
sometimes, the compiler (with no optimization flags enabled) would
squeeze in some other operation in those cycles that didn't interfere
with the branch. Thus, that operation was effectively done in parallel
with other tasks. Also, the same processor (a TI DSP, if you care) had
several multipliers on it, so a statement like:
x = (a*b) + (c*d) + (e*f) + (g*h);
could be executed largely in parallel. Also consider that the compiler
might inline certain functions, optimize away certain operations, and
do other things that could throw off your calculations. Add to that
cache and locality of reference issues, and you've pretty much
invalidated most simplistic operation counting schemes.
Anyway, the issue is that your guess about how fast the code is based
on the number of additions and so forth is not necessarily (or even
likely to be) an accurate measurement of how the *compiled* code
actually performs.
If your system didn't come with a profiler, use Google to find one for
your system. It will help you *accurately* estimate the speed and find
what portions need optimized. Certain products might also give you
statistics on certain types of operations.
Cheers! --M