
Boost : 
From: Pavel Vozenilek (pavel_vozenilek_at_[hidden])
Date: 20040214 21:39:08
"Hurd, Matthew" <hurdm_at_[hidden]> wrote
> This is an Intel P43.2 I'm running on now and I'm getting output like:
>
> boost function measurements: median time = 250.698 microseconds
> direct inline: median time = 250.691 microseconds
>
> You see here I look at the median time for boost function and
> directinline and see only a 7 ns difference which is probably smaller
> than I can truly measure I suspect...
>
I wrote my own test (the most simple one, call function/boost::fn
in loop and measuring total time).
The numbers I got give me ~18 microseconds overhead per single
boost::function call (raw call takes ~404 microseconds).
I use Intel C++ 8.0 plugged in VC6 IDE,, release mode,
Athlon XP 2200+, W2K.
/Pavel
 test (shortened) 
#define MAX_FN_LOOP 1e5
static double not_empty() {
static double sum;
static double i;
sum = 0.0;
for (i = 0.0; i < MAX_FN_LOOP ; ++i) {
sum += i * i;
}
return sum;
}
void test1()
{
DWORD tick1 = GetTickCount();
double x = 0;
for (int i = 0; i < 100000; ++i) {
x += not_empty();
}
DWORD tick2 = GetTickCount();
}
void test2()
{
DWORD tick1 = GetTickCount();
boost::function< double (void)> fn = ¬_empty;
double x = 0;
for (int i = 0; i < 100000; ++i) {
x += fn();
}
DWORD tick2 = GetTickCount();
}

test1() and test2() took each 3040 seconds.
GetTickCount() resolution is at least 10 milliseconds.
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