Re: PPC64 Illegal Instruction
Hi!
On 3/4/19 10:24 AM, Gabriel Paubert wrote:
> No, the difference is VSX. Altivec is the same instruction set, whether
> on G4, G5, Power5 and later (IBM Power4 did not have Altivec, Power5 did,
> VSX was added to Power7).
Okay, I had the assumption that AltiVec and VSX were the same. Thanks for
the clarification. The amount of different POWER targets is really
confusing.
> G5 or PPC970 is actually closer to Power5 from this point of view.
Yeah, if POWER4 was without AltiVec, that makes sense.
> To support everything you would ideally need 3 versions (or 3
> libraries):
> - no vector instructions (basic Power4)
> - Altivec (G5, P5, P6)
> - VSX (P7 and later)
We don't want to support anything newer than P5 really. POWER4
and POWER5 is enough.
> However, the big jump for performance is likely provided by Altivec.
Yeah, I agree.
> Do you really want to support base Power4 (no Altivec) or not?
>
> If not, a single version (Altivec and no VSX) is probably the simplest.
The problem is that some people want to run the ppc64 port on hardware
which doesn't support Altivec like those embedded E5550 CPUs. There was
actually a large archive rebuild to lower the baseline for that reason
(the discussion is in the mailing list archives for this mailing list).
We could maybe have a poll which baseline users prefer.
FWIW, the x265 bug originally reported by Noah should be fixed now.
@Noah: Can you confirm the issue is resolved for you?
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - glaubitz@debian.org
`. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
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