Dear Boosters I am using quite intensively boost::signals but I noticed a relatively high cost. I wrote a small test program that confirmed it with a comparison to sigc++-2.0. The code has been compiled with g++-3.3 -O3 and this is a very recent boost cvs snapshot(compiled in release mode). It was run on a Debian(sid)/GNU/Linux ibm thinkpad T40p (pentium M) I vary the number of slots (0 to 4) and calls and I have a dummy slot class and a less dummy slot class to test with. here are the timings: ================================================================== call dummy::operator() #Slots #Calls boost::signals sigc++-2.0 Ratio 0 100 0 0 nan 0 1000 0 0 nan 0 10000 0 0 nan 0 100000 0.05 0 inf 0 1000000 0.5 0.01 50 0 10000000 4.95 0.11 45 1 100 0 0 nan 1 1000 0 0 nan 1 10000 0.01 0.01 1 1 100000 0.1 0.02 5 1 1000000 1.08 0.14 7.71429 1 10000000 10.55 1.34 7.87313 2 100 0 0 nan 2 1000 0 0 nan 2 10000 0.02 0 inf 2 100000 0.14 0.02 7 2 1000000 1.45 0.14 10.3571 2 10000000 14.6 1.46 10 3 100 0 0 nan 3 1000 0 0 nan 3 10000 0.02 0 inf 3 100000 0.19 0.01 19 3 1000000 1.84 0.15 12.2667 3 10000000 18.44 1.53 12.0523 ================================================================== call A::operator() #Slots #Calls boost::signals sigc++-2.0 Ratio 0 100 0 0 nan 0 1000 0.01 0 inf 0 10000 0 0 nan 0 100000 0.05 0 inf 0 1000000 0.48 0.01 48 0 10000000 4.87 0.11 44.2727 1 100 0 0 nan 1 1000 0 0 nan 1 10000 0.02 0 inf 1 100000 0.12 0.01 12 1 1000000 1.15 0.22 5.22727 1 10000000 11.46 2.17 5.28111 2 100 0 0 nan 2 1000 0.01 0 inf 2 10000 0.01 0.01 1 2 100000 0.16 0.03 5.33333 2 1000000 1.61 0.32 5.03125 2 10000000 16.17 3.14 5.14968 3 100 0.01 0 inf 3 1000 0 0 nan 3 10000 0.02 0 inf 3 100000 0.21 0.04 5.25 3 1000000 2.09 0.41 5.09756 3 10000000 20.83 4.06 5.13054 Am I using boost::signals the wrong way? has boost::signals some added features that reduce its performance ? I apologize in advance if it has already been discussed before but I didnot find a relevant discussion in the archives or on google. I found some feature comparison here http://www.3sinc.com/opensource/boost.bind-vs-sigc2.html For my application the number of calls are typically between 1e6 and 1e8 with a few slots (1 to 10 ). The cost of boost::signals framework is quite high. Best regards C. -- Christophe Prud'homme Office MA B2 534 CMCS-IACS EPFL CH-1015 Lausanne, Switzerland Tel: +41 (0)21 693 25 47 Fax: +41 (0)21 693 43 03