The problem in the updated version I linked to seems to be extracting the type of the properties of nested composite types so wondered if you had any general comment to that, i.e. using complicated types as inputs.
2014-12-12 10:25 GMT-05:00 Stefan Karpinski <ste...@karpinski.org>: > > Yikes, that's much harder to read than the original. Making the globals > const is a simple change and the fact that this improves the performance so > much shows that all those type annotations are not necessary. The only > issue with the original code was non-constant globals. We can also change > the globals to function arguments and the problem goes away: > > julia> @time Ke1(N); > elapsed time: 0.237183958 seconds (131200224 bytes allocated, 34.34% gc > time) > > julia> @time Ke2(N); > elapsed time: 0.021313495 seconds (400 bytes allocated) > > The gist has both the const and function-arg versions: > > https://gist.github.com/StefanKarpinski/e1d7d8804e373cc1de07 > > > On Fri, Dec 12, 2014 at 10:12 AM, Andreas Noack < > andreasnoackjen...@gmail.com> wrote: > >> Stefan, please consider the updated version >> >> https://gist.github.com/PetrKryslUCSD/7bd14515e1a853275923 >> >> which has no global variables. >> >> 2014-12-12 10:07 GMT-05:00 Stefan Karpinski <ste...@karpinski.org>: >> >> From the original version of the code I see this timing after code gen: >>> >>> julia> @time Ke1(N); >>> elapsed time: 0.251365495 seconds (134400208 bytes allocated, 30.13% gc >>> time) >>> >>> julia> @time Ke2(N); >>> elapsed time: 3.923532621 seconds (996800384 bytes allocated, 13.97% gc >>> time) >>> >>> After making all the globals const, I see this: >>> >>> julia> @time Ke1(N); >>> elapsed time: 0.273683599 seconds (131200208 bytes allocated, 28.52% gc >>> time) >>> >>> julia> @time Ke2(N); >>> elapsed time: 0.026985097 seconds (384 bytes allocated) >>> >>> Type annotations everywhere are neither necessary nor recommended. It is >>> recommended not to use lots of non-constant globals. >>> >>> >>> On Fri, Dec 12, 2014 at 9:36 AM, Tim Holy <tim.h...@gmail.com> wrote: >>> >>>> On Thursday, December 11, 2014 08:10:38 PM Petr Krysl wrote: >>>> > The moral of this story is: If you can't or won't declare every >>>> single >>>> > variable, don't do loops. They are likely to be a losing proposition. >>>> >>>> Just to follow up further, this is not at all the right moral to absorb >>>> from >>>> this. A better set of morals is: >>>> - use code_typed or TypeCheck or Lint to diagnose problems >>>> - remember that julia optimizes functions as a unit. Therefore, in a >>>> loop with >>>> a type issue, one "brute force" solution is to create a separate >>>> function just >>>> for running that loop. The types will be known when that function gets >>>> compiled (even if you don't annotate anything with their types), and so >>>> your >>>> type problem should evaporate. >>>> >>>> --Tim >>>> >>>> >>> >> >
