[gambit-list] a simple question for optimization
Bradley Lucier
lucier at math.purdue.edu
Fri Apr 10 20:52:28 EDT 2015
> On Apr 10, 2015, at 6:12 PM, Bradley Lucier <lucier at math.purdue.edu> wrote:
>
> Long answer:
>
> [Media-Mac-mini-3:~] lucier% time ./pi 1000000
> (time (cpi k))
> 18 ms real time
> 17 ms cpu time (17 user, 0 system)
> no collections
> 64 bytes allocated
> no minor faults
> no major faults
> 3.1415946535887644
> 0.021u 0.009s 0:00.09 22.2% 0+0k 0+0io 753pf+0w
>
> So that last bit didn't help too much.
>
> On my machine I get
>
> [Media-Mac-mini-3:~] lucier% g++ -Wall -W -Ofast pi.cc
> pi.cc:12:14: warning: unused parameter 'argc' [-Wunused-parameter]
> int main(int argc, char* argv[]) {
> ^
> 1 warning generated.
> [Media-Mac-mini-3:~] lucier% time ./a.out 1000000
> 3.1415926535899388
>
> 0.018200999999999998
> 0.018u 0.001s 0:00.02 50.0% 0+0k 0+0io 0pf+0w
>
> Pretty close.
Sorry, I didn’t use the same compiler for Scheme and C++:
[Media-Mac-mini-3:~] lucier% gsi -v
v4.7.4 20150228031125 x86_64-apple-darwin14.1.0 "./configure 'CC=/pkgs/gcc-4.9.1/bin/gcc' '--enable-single-host' '--enable-multiple-versions'"
[Media-Mac-mini-3:~] lucier% /pkgs/gcc-4.9.1/bin/g++ -Wall -W -Ofast pi.cc
g++: warning: couldn't understand kern.osversion '14.3.0
pi.cc:12:14: warning: unused parameter 'argc' [-Wunused-parameter]
int main(int argc, char* argv[]) {
^
[Media-Mac-mini-3:~] lucier% time ./a.out 1000000
3.1415926535897647
0.0090840000000000001
0.010u 0.002s 0:00.36 2.7% 0+0k 0+0io 57pf+0w
So the C++ program is still about twice as fast (if you can believe timings that small).
Brad
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