Hello Dmitry, >> This is a call for testers concerning an experimental OCaml compiler >> back-end that uses SSE2 instructions for floating-point arithmetic.[...] > > I cannot provide any benchmark yet
Too bad :-( I got very little feedback to my call: just one data point (thanks Gaetan). Perhaps most OCaml users interested in numerical computations have switched to x86-64bits already? At any rate, given such a lack of interest, this x86-32/SSE2 port isn't going to make it into the OCaml distribution. > but even not taking into account > the better register organization there are at least two areas where > SSE2 can outperform x87 significantly. > > 1. Float to integer conversion > Is quite inefficient on x87 because you have to explicitly set and > restore rounding mode. Right. The mode change makes the conversion about 10x slower on x87 than on SSE2. Apparently, float->int conversion is uncommon is numerical code, otherwise we'd observe bigger speedups on real applications... > 2. Float compare > Does not set flags on x87 so The SSE2 code is prettier than the x87 code, but this doesn't seem to translate into a significant performance gain, in my limited testing. > As for SSE2 backend presented I have some thoughts regarding the code > (fast math functions via x87 are questionable, Most x86-32bits C libraries implement sin(), cos(), etc with the x87 instructions, so I'm curious to know what you find objectionable here. > optimization of floating compare etc.) Where to discuss that - just > here or there is some entry in Mantis? Why not start on this list? We'll move to private e-mail if the discussion becomes too heated :-) - Xavier Leroy _______________________________________________ Caml-list mailing list. Subscription management: http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list Archives: http://caml.inria.fr Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
