Re: [fpc-pascal] for loops performance problems?
Hello. Please take a look at this: https://www.mail-archive.com/fpc-pascal%40lists.freepascal.org/msg46162.html and this: http://www.mail-archive.com/mseide-msegui-talk@lists.sourceforge.net/msg11078.html fpc has a huge problem for float calculation. It makes fpc not competitive for audio libraries/programs that use DSP. Decent today's audio stuffs do use float 32 résolution for samples. Fre;D - Many thanks ;-) -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/for-loops-performance-problems-tp5729198p5729203.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] for loops performance problems?
Hi, On Wed, 5 Jul 2017, fredvs wrote: > Please take a look at this: > > https://www.mail-archive.com/fpc-pascal%40lists.freepascal.org/msg46162.html > > and this: > > http://www.mail-archive.com/mseide-msegui-talk@lists.sourceforge.net/msg11078.html > > fpc has a huge problem for float calculation. > > It makes fpc not competitive for audio libraries/programs that use DSP. > Decent today's audio stuffs do use float 32 résolution for samples. This problem has nothing to do with the topic. No, the asker's posted code is not slow because of this or similar problem, but because it does 10+ function calls inside a tightloop. Charlie___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] for loops performance problems?
Karloy, I replaced the calls to World.Vertex/.TexCoord/.Color with a local vertex buffer (an array of TColorTexVertex) eliminating the function calls you mentioned. The frames per seconds with vsync off is identical, so I'm pretty sure that's not causing the slow down. It's either that the addition/multiplication of floats given the font map (heights/widths stored in an array) is inefficient or that there is something about the nature of a for..loop that is causing it to be slow. I will investigate further. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] for loops performance problems?
Hi, On Wed, 5 Jul 2017, Anthony Walter wrote: > I replaced the calls to World.Vertex/.TexCoord/.Color with a local > vertex buffer (an array of TColorTexVertex) eliminating the function > calls you mentioned. The frames per seconds with vsync off is identical, > so I'm pretty sure that's not causing the slow down. It's either that > the addition/multiplication of floats given the font map (heights/widths > stored in an array) is inefficient or that there is something about the > nature of a for..loop that is causing it to be slow. If you still think that loop causes the slowdown, can you post the generated assembly of it with -al? Otherwise it's really just guesswork. Also, since you're compiling for ARM if I'm correct, make sure that you A., using the hardfloat target, and not actually using the softfpu... B., your data strutures are properly aligned, and any underlying records are *NOT* declared as packed. C., you're actually doing aligned accesses indeed, so there are no hidden exceptions involved from the kernel side, handling the load/store of your values. The other example which bubles up again and again, is down to the fact, that FPC doesn't do autovectorization of that example, while other compilers, mainly LLVM does. With scalar code, FPC is not that far behind, if at all. Charlie ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
