[boost] [signal] performance

From: Vladimir Prus (ghost_at_[hidden])
Date: 2005-12-19 11:26:00

Hi, I've just tried to measure performance of Boost.Function and Boost.Signals 
using the following simple program:

    #include <boost/function.hpp>
    #include <boost/signals.hpp>
    using namespace std;

    void do_nothing() {}

    int main()
    {
        boost::function<void (void)> f = do_nothing;
        void (*pf)(void) = &do_nothing;
        boost::signal<void (void)> s;
        s.connect(&do_nothing);

        for(int i = 0; i < 10000000; ++i)
           s();

        return 0;
    }

and trying calls to 's()', 'pf()' and 'f()'. The timings are, on an Athlon 
1700 with g++ 3.3.5 and -O3:

Function pointer: 0.05 secs
Boost.Function:   0.2 secs
Boost.Signals:    9.8 secs

Boost.Function is 4 times slower than function pointer, which seems decent for 
me (not that I mind further improvement). But Boost.Signals is nearly 50 
times slower that Boost.Function, and nearly 200 times slower than function 
pointer.

Any chance this will be improved? Say, I don't care about combining the 
results of signals invocation, or any connection tracking -- I just want to 
use boost::signals as more convenient variant of vector<boost::function>. Is 
it possible to have some preprocessor define that throws away all advanced 
functionality? Or a base class, say "lightweight_signal" that has only 
basics?

TIA,
Volodya