Re: [boost] units: performance testing

From: Lewis Hyatt (lhyatt_at_[hidden])
Date: 2007-03-28 16:26:56

Matthias Schabel wrote:

> Just for reference, using gcc 4.0.1 on Mac OSX (G5 2GHz) I get no  
> overhead :

I just tried gcc 4.0.2 on AMD Opteron 2.2 GHz, and I get no overhead as 
well:

f(x,y,z) took 3.21 seconds to run 1e+09 iterations with double = 
1.24611e+09 flops
f(x,y,z) took 3.18 seconds to run 1e+09 iterations with quantity<double> 
= 1.25786e+09 flops
g(x,y,z) took 3.2 seconds to run 1e+09 iterations with double = 1.25e+09 
flops
g(x,y,z) took 3.19 seconds to run 1e+09 iterations with quantity<double> 
= 1.25392e+09 flops

I guess gcc 3.4.4 just doesn't cut it these days!

Steven Watanabe wrote:

 > unit_example_14.cpp passes double by value
 > and quantity by reference.  When I looked
 > at the assembler output from msvc 8.0 it looked
 > like this had a noticable effect (the quantity
 > code was quite a bit more complex).

I just tried it, and changing the pass by value to pass by reference did 
not affect the timings on gcc 3.4.4. (I did not confirm but I believe 
gcc is inlining the function call anyway.)

-Lewis