[Boost-users] performance of template expression

From: divyank shukla (divyank_s_at_[hidden])
Date: 2006-07-31 11:05:33

Hi All
 Am trying to work for real time environment 
I wanted to know which if the fact that 

 This appeared in one of the articles :

http://citeseer.ist.psu.edu/striegnitz00expression.html

g++ compilers fare almost 7 times as bad to hand 
generated code.

snip....

The performance of lambda function, we used the 
expression template aware Vec3
class that has been described in section 3.1. We
measured the time to add four instances of Vec3 by
using these methods:

loop: we manually coded a loop that iterates through
the vector components and performs the
addition,

expression templates: we simply wrote e = a + b + c +
d, were a - e are all of type Vec3
and

lambda function: we used lambda(w,x,y,z, w + x + y +
z)(a,b,c,d).
All those expression were evaluated fifty million
times on a SunUltra 10 with a 333MHz
UltraSparcIIi processor. We used Kuck and
Associates’ KCC version 4.0 with either SUN’s C
5.0
or Gnu’s C 2.95.2 as possible backend C compiler.
Furthermore, we investigated GNU’s C++
compiler 2.95.2.

snip....

My question is does the performance penalty still
exist with g++(4.1) compilers as against boost::lambda
functions.

regards
  divyank

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