Re: PPC64 port status
On Mar 31, 2016, at 8:34 AM, Lennart Sorensen <firstname.lastname@example.org> wrote:
> On Thu, Mar 31, 2016 at 01:18:53AM -0700, Rick Thomas wrote:
>> The altivec instructions and other optimizations speed-up significantly certain kinds of programs on CPUs that can use them. It would be a shame to loose the optimized versions by dropping back to the lowest common denominator CPU architecture. Would it be possible to create and support a sub-architecture that provided altivec optimized versions of packages?
> No idea, but certainly in the past i386 did not have sub architectures for
> sse or mmx or anything else. There were some programs and libraries that
> did have optimizations when they detected such support, and I believe
> that is also true with powerpc already. libc does do cpu specific
> optimizations at runtime for strcpy and such.
> Any examples of programs where altivec makes a measurable improvement?
> Len Sorensen
The main beneficiaries of vector instruction extensions are users of scientific, cryptographic, and audio/visual libraries. Basically anything that wants to do simple, repetitive operations on long strings of data at memory speed.