--- Carsten Haitzler <[EMAIL PROTECTED]> a �crit : > On Thu, 4 Sep 2003 00:52:41 +0200 (CEST) emmanuel > ALLAUD <[EMAIL PROTECTED]> > babbled: > > > Hi all, > > in the thread about RENDER extension, it has beem > > mentionned that XFree was performing much slower > (ie 2 > > or 3 times slower) than imlib2 (sorry I don't > really > > remember in which tasks). The reason seemed to > boil > > down to the fact that imlib2 has arch specific asm > > instructions (I think mostly for x586 via MMX or > SSE > > or whatever) for certain crucial functions. > > My question is why not do that also in XFree > > (borrowing/adapting codes from images manipulation > > libs)? > > By choosing carefully the functions to optimize > (that > > would mean only a few small function so that the > > maintainance is as easy as possible) we should > avoid > > too much mess, keeping portability by using the > "old" > > functions for arches with no specific > optimizations. > > Does that sound reasonnable? > > Bye > > Manu >
<snip> > so summary: > > the problem is twofold. > > 1. the software fallbacks in xrender - if they have > mmx/sse or not are simply > not being given a chance to perform at full cpu > capacity. adding mmx/sse won't > help until this is solved. once this is solved > mmx/sse/altivec etc. could get > you up to a double speedup again (in my experience), > maybe even more. but first > this needs to be fixed. > > 2. only 1 of all my tests ever went through > acceleration at all. the other 6 > tests all were software only. even the first test > sometimes wasn't hardware > either. when it was hardware accelerated it could > have been a LOT LOT LOT faster > in the cases i saw > > i will also point out that my performance tests also > were measuring only a small > subset of xrender's operations - but they were the > operations i personally use > the most, and definitely to me would appear to be, > in general, some of the most > commonly used ones. > OK that is for xrender software fallbacks, and basically you are telling that even the generic code could be substantially faster evn without using asm arch specific code? That would certainly be the first thing to fix. I was also pointing at other functions (not only in xrender) that could benefit some arch specific optimizations, but I would like people actually knowing the code (I'm not in that population ;-) to speak up and tell if this is doable without compromising portability (I mean without too much hassle), and if it is worth doing it. Bye Manu ___________________________________________________________ Do You Yahoo!? -- Une adresse @yahoo.fr gratuite et en fran�ais ! Yahoo! Mail : http://fr.mail.yahoo.com _______________________________________________ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
