[Halld-offline] stl vector

[Paul Eugenio]

Hi Dave,

I am impressed by the compiler optimization.    After debugging, I usually use -O optimization, but I have to admit I did not expect near full recover.  

P.


On May 9, 2011, at 12:21 PM, David Lawrence wrote:

> 
> Hi Paul,
> 
>     I actually tried your code on my 2.33GHz Core 2 duo laptop running 
> OS X 10.5 and got a much larger discrepancy. However, when I turned on 
> optimization, the discrepancy disappeared. Have you tried this test with 
> optimization turned on?
> 
> 
> No Optimization
> --------------
> 1:13.83 STL
> 0:04.83 double array
> 
> -O
> --------------
> 0:03.63 STL
> 0:03.64 double array
> 
> -O2
> --------------
> 0:03.68 STL
> 0:03.64 double array
> 
> 
> 
> Full transcript of session is below.
> 
> Regards,
> -Dave
> 
> STL-vector
> -------------------
> wifi-80-86:STLTest>g++ stl-test.cc -o stl-test
> wifi-80-86:STLTest>time ./stl-test
> sumXsq = 2.69986e+17
> 71.068u 0.584s 1:13.83 97.0%    0+0k 0+0io 0pf+0w
> wifi-80-86:STLTest>g++ -O stl-test.cc -o stl-test
> wifi-80-86:STLTest>time ./stl-test
> sumXsq = 2.69986e+17
> 3.498u 0.031s 0:03.63 96.9%    0+0k 0+0io 0pf+0w
> wifi-80-86:STLTest>g++ -O2 stl-test.cc -o stl-test
> wifi-80-86:STLTest>time ./stl-test
> sumXsq = 2.69986e+17
> 3.496u 0.033s 0:03.68 95.6%    0+0k 0+0io 0pf+0w
> 
> 
> double with malloc
> -----------------
> wifi-80-86:STLTest>g++ stl-test.cc -o stl-test
> wifi-80-86:STLTest>time ./stl-test
> sumXsq = 0
> 4.674u 0.036s 0:04.83 97.3%    0+0k 0+0io 0pf+0w
> wifi-80-86:STLTest>g++ -O stl-test.cc -o stl-test
> wifi-80-86:STLTest>time ./stl-test
> sumXsq = 0
> 3.498u 0.032s 0:03.64 96.7%    0+0k 0+0io 0pf+0w
> wifi-80-86:STLTest>g++ -O2 stl-test.cc -o stl-test
> wifi-80-86:STLTest>time ./stl-test
> sumXsq = 0
> 3.489u 0.027s 0:03.64 96.1%    0+0k 0+0io 0pf+0w
> 
> 
> On 5/9/11 11:58 AM, Paul Eugenio wrote:
>> g++     stl-test.cc   -o stl-test
> _______________________________________________
> Halld-offline mailing list
> Halld-offline at jlab.org
> https://mailman.jlab.org/mailman/listinfo/halld-offline

--
Prof. Paul Eugenio
Florida State University
Department of Physics
Tallahassee, Florida,  USA 32306

(850) 644-2585
eugenio at fsu.edu