Messages in this thread | | | From | "Alexander van Heukelum" <> | Subject | Re: Alternative implementation of the generic __ffs | Date | Sat, 19 Apr 2008 22:26:34 +0200 |
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On Sat, 19 Apr 2008 11:17:01 -0700, "Joe Perches" <joe@perches.com> said: > On Sat, 2008-04-19 at 14:10 +0200, Alexander van Heukelum wrote: > > I've added that to the benchmark, which you can now find here: > > http://heukelum.fastmail.fm/ffs/.
Thanks! Added the version you sent to the program and added the results of the ARM processor to the page.
More ideas welcome ;).
> retested on arm: > > $ gcc -Os -fomit-frame-pointer ffs.c > $ ./a.out > Original: 3170 tics, 8326 tics > New: 4214 tics, 8793 tics > Smallest: 4023 tics, 7733 tics > Small const: 3442 tics, 6188 tics > Empty loop: 1517 tics, 2243 tics > > $ gcc -O2 -fomit-frame-pointer ffs.c > $ ./a.out > Original: 3172 tics, 7832 tics > New: 4805 tics, 8790 tics > Smallest: 4405 tics, 7154 tics > Small const: 3442 tics, 5612 tics > Empty loop: 1516 tics, 2145 tics > > $ gcc -O3 -fomit-frame-pointer ffs.c > $ ./a.out > Original: 3080 tics, 7709 tics > New: 4723 tics, 8656 tics > Smallest: 4333 tics, 7121 tics > Small const: 3379 tics, 5483 tics > Empty loop: 1447 tics, 2016 tics > > > Testing the same with > > "return x4 + x3 + x2 + x1 + x0;" as the last line would be > > interesting too. > > Adding is slower: > > $ gcc -Os -fomit-frame-pointer ffs.c > $ ./a.out > Original: 3152 tics, 8310 tics > New: 4214 tics, 8789 tics > Smallest: 4024 tics, 7737 tics > Small const: 3538 tics, 6295 tics > Empty loop: 1517 tics, 2243 tics > > $ gcc -O2 -fomit-frame-pointer ffs.c > $ ./a.out > Original: 3184 tics, 7849 tics > New: 4790 tics, 8814 tics > Smallest: 4406 tics, 7161 tics > Small const: 3538 tics, 5806 tics > Empty loop: 1521 tics, 2153 tics > > $ gcc -O3 -fomit-frame-pointer ffs.c > $ ./a.out > Original: 3091 tics, 7694 tics > New: 4718 tics, 8656 tics > Smallest: 4333 tics, 7124 tics > Small const: 3467 tics, 5687 tics > Empty loop: 1445 tics, 2066 tics > > -- Alexander van Heukelum heukelum@fastmail.fm
-- http://www.fastmail.fm - And now for something completely different
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