Re: Smoking gun: NetBSD 6.0.1 userland instability

[Donald Lee <MacPPC2%c.icompute.com@localhost>]

At 9:25 PM -0500 3/7/13, Michael wrote:
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>Hello,
>
>On Mar 7, 2013, at 1:59 PM, Donald Lee wrote:
>
>>>>> In the old days, I would just use "-g", and presume that the
>>>>> optimization was disabled, but modern compilers don't do that any
>>>>> more.
>>>> The only thing -g should do is enable debugging symbols; it doesn't
>>>> generally have an effect on optimization.  Perhaps you mean -O0?
>>>
>>> No, I think more likely -dgl- was talking about "the old days", when,
>>> yes, -g did indeed kill the optimizer.  It's been a while, but there
>>> was such a time.
>>
>> ...back when the dinosaurs roamed the earth, and computers had front panels
>> with switches and lights.
>>
>> Thus sayeth the Old Guys. ;->
>>
>> If anyone can give me some confidence in what switches I need to use to
>> get what we need, I can do the experiment(s).
>
>- -mno-altivec or -mcpu=750 ( or anything else that's not a g4 or g5 )
>That doesn't keep libc from running altivec code though.

libc detects the CPU on the fly and uses different code to do its
job on the fly?  That's either cool - or terrifying. ;->
(terrifying for the poor shmuck trying to debug altivec kernel prob)

Given that libc doesn't do that, we would have to build all our libraries
with the lowest-common-denominator instruction set, or somehow trap/emulate
the altivec like m68K FPU does.  I don't think our install/build process
builds multiple libraries for different PPC CPU variations, does it?

My ignorance is vast in this area.....

-dgl-