On Fri, Jul 16, 2021 at 2:59 AM John Paul Adrian Glaubitz <[email protected]> wrote: > > On 7/15/21 5:49 PM, Christian Zigotzky wrote: > > I disagree too because the performance of software with AltiVec support > > isn't as > > high as expected. I tested it a lot because we have AltiVec and Non-Altivec > > machines > > here. We changed to Non-AltiVec compiled software a while ago. > > It depends on the workload, of course. Anything that does SIMD like matrix > multiplications > in multimedia or scientific computing will, of course, profit from enabling > AltiVec. > > No one claimed that AltiVec, MMX or SSE will just improve everything.
+1 I've found a few algorithms that were profitable on ARM and x86, but not profitable with Altivec. The LEA algorithm comes to mind: https://github.com/weidai11/cryptopp/blob/master/lea_simd.cpp#L46. Altivec runs about 5x slower than C++. > > We and the MintPPC team had some problems with the VLC media player on our > > Non-AltiVec > > machines a year ago because it is only available in an AltiVec version. > > The MintPPC team had to recompile it. [1] > > We also had to recompile the version 3.0.12 of VLC because of the AltiVec > > dependency again. [2] > > I would argue that there are far more users with PowerMacs which all support > AltiVecs than > with obscure embedded machines. As I said, some packages like nss2 already > enabled AltiVec > by default. Does it have to be one or the other? Can't you have both? Jeff
