Re: Performance difference 32bit/64bit userland
On Wed, Feb 08, 2017 at 11:21:00AM -0200, Breno Leitao wrote:
> On 02/07/2017 07:22 PM, Lennart Sorensen wrote:
> > ppc64el is different since it is targeting systems where the applications
> > are expected to need a lot of ram, and switching the little endian
> > improves performance when working with GPUs (which are all designed
> > for the x86 little endian world). At the same time being able to
> > assume power8 as a minimum cpu means you can gain some instruction set
> > improvements that normal powerpc can't assume.
>
> Correct. And we can't do 32-bits userspace also, since we do not have a
> 32-bits little endian ABI. For ppc64el, bi-arch does not seem to be a valid
> feature.
Yes, I don't think ppc64el architecture has defined a 32 bit variant.
I don't think they see any point.
Of course linux could run little endian on powerpc if someone wanted to.
After all Windows NT did so the CPUs (for the most part) can do it.
--
Len Sorensen
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