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Re: Performance difference 32bit/64bit userland

On Wed, Feb 8, 2017 at 2:21 PM, Breno Leitao <brenohl@br.ibm.com> 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.

I always assumed it was possible to run ppc32 (be) or ppc64 (be)
userlands on a ppc64el system. Is this a restriction at Linux level or
hardware level ?


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