Re: New architecture ppc64el on Debian
On Mon, Sep 23, 2013 at 11:43 PM, Lennart Sorensen
<lsorense@csclub.uwaterloo.ca> wrote:
> On Sun, Sep 22, 2013 at 06:08:12PM +0900, Joel Rees wrote:
>> I suppose I'm not really one privileged to express these reactions,
>> but I tend to be a loose cannon sometimes.
>>
>> ???
>>
>> (Checking my calendar. Nope, I haven't suddenly slipped back to the
>> early 1990s.)
>>
>> (Still puzzled.)
>
> Well I see patches for linux on powerpc in little endian mode (it
> is software selectable on most powerpc chips as far as I know) were
> submitted in August of this year, and patches to qemu were done around
> the same time to support emulating little endian mode powerpc.
Ergo, there hasn't been sufficient support for least significant byte
first mode to demonstrate that the CPU can actually do it. Makes more
sense when I think about it that way.
>> So, pardon me for being dense, but is the build process really going
>> to be all that much more difficult than putting a compiler flag for
>> least significant byte first in the make files and typing make?
>
> Well you take a compiler that generates code for powerpc in little
> endian mode, and then you build stuff. Then you go fix all the code
> where people incorrectly assumed powerpc meant big endian. I imagine
> there is quite a bit of that around. Also anything with powerpc assembly
> code might need fixing.
And naive guys like me would assume that developers would check
something more fundamental than the name of the processor when trying
to decide how to fight with the automatic optimizations.
I tend to forget I'm not the only impatient. non-omniscient programmer
in the world. :-/
>> [...]
> Well you could always complain about IBM choosing the x86 in the first
> place, or complain that people bought IBM's machines in the first place
> at a time when lots of other machines were using m68k chips instead.
Which I tend to do a lot more than some people think I should.
Although I am quite sanguine to the engineering management issues of
putting a too-powerful CPU in the hands of the engineers and letting
that fact slip to the guys in charge of adding features to the design.
> Seems a bit late to fix it now though. So perhaps this is a sensible
> move on IBM's part.
It occurs to me that the reason a least-significant-byte-first PPC
port has failed to get traction until now is that no sensible engineer
has wanted to waste his own time working on it. (... management always
being too focused on immediate profits.) So the "news" in IBM's
announcement is that they are deciding to put company money behind it.
If I were they, I think I would be more focused on fixing the
management issues that allowed the cell version of the PPC to go to
production as a clot of customer (Sony) requested features instead of
an engineered product. It seems to me that they've now kicked out the
wrong managers and are repeating the mistakes. (Standard Operating
Procedure, as they say.)
ppc-le or whatever it ends up being called shouldn't take a huge
announcement and tons of money, even at this point. Three extra
servers to dedicate to little-endian is at most, what, USD 30,000?
(Actual cost to IBM would be more like $3,000, I think, but they can
probably expense the full advertised price.) The engineering support
is more expensive, but from Breno's posts it looks like they don't
understand the process here. Does the Fedora community give IBM some
kind of special fast-track support that they've gotten spoiled by?
The fact that an unofficial port doesn't yet exist points to a big
part of the problem, too.
And I suppose this entire post is a little off-topic.
--
Joel Rees
Be careful where you see conspiracy.
Look first in your own heart.
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