Le Tue Feb 24 2015 at 12:48:10 PM, Michael Zimmermann < sigmaepsilo...@gmail.com> a écrit :
> thx I'll try that but wouldn't it make more sense to implement a hw > version of this function?(do I need a different compiler?) > > AFAIK there isn't a consistent division instruction across all ARMs and which is enabled on boot time. You can implement hw version of division but it will crash on some machines. Division is a slow operation on any platform and should be avoided as far as possible. > Almost all modules use this call and I guess it could really improve > the performance. > > On Tue, Feb 24, 2015 at 12:27 PM, Vladimir 'phcoder' Serbinenko > <phco...@gmail.com> wrote: > > > > > > Le Tue Feb 24 2015 at 11:01:03 AM, Michael Zimmermann > > <sigmaepsilo...@gmail.com> a écrit : > >> > >> the function seems to use __aeabi_uidiv. I'm not sure if this is a sw > >> or hw implementation. > > > > software. Try attached patch > >> > >> Full code: > >> ASM: http://pastebin.com/FnPRZt1H > >> pseudo-C: http://pastebin.com/dH3YBk46 > >> > >> On Tue, Feb 24, 2015 at 10:51 AM, Vladimir 'phcoder' Serbinenko > >> <phco...@gmail.com> wrote: > >> > Did you try to look at ASM of the function in question? Do you compile > >> > to > >> > thumb? Multiplication sometimes generates function calls in thumb. Try > >> > marking the scaling function as arm explicitly > >> > > >> > Le 2015-02-24 10:39, "Michael Zimmermann" <sigmaepsilo...@gmail.com> > a > >> > écrit > >> > : > >> >> > >> >> Any ideas what could slow down the image scaling algorithm? > >> >> The only reasons I could think of would either be slow memory or some > >> >> compiler problems. Since my Ram is mapped cachable I don't think the > >> >> RAM is too slow. > >> >> > >> >> I even forces using the Nearest neighbor algorithm already. It speeds > >> >> things up a lot but it's not as fast as you'd expect. > >> >> > >> >> Some technical info: > >> >> ARMv7 > >> >> Linaro GCC 4.9 > >> >> MMU setup is done by the previous bootloader(I disabled GRUB's > (uboot) > >> >> MMU setup - it prooved to be faster) > >> >> > >> >> _______________________________________________ > >> >> Grub-devel mailing list > >> >> Grub-devel@gnu.org > >> >> https://lists.gnu.org/mailman/listinfo/grub-devel > >> > > >> > > >> > _______________________________________________ > >> > Grub-devel mailing list > >> > Grub-devel@gnu.org > >> > https://lists.gnu.org/mailman/listinfo/grub-devel > >> > > >> > >> _______________________________________________ > >> Grub-devel mailing list > >> Grub-devel@gnu.org > >> https://lists.gnu.org/mailman/listinfo/grub-devel > > > > > > _______________________________________________ > > Grub-devel mailing list > > Grub-devel@gnu.org > > https://lists.gnu.org/mailman/listinfo/grub-devel > > > > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > https://lists.gnu.org/mailman/listinfo/grub-devel >
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