Phase out 32bit ppc due to bugfix and maintenance burden

Tue May 13 20:29:38 UTC 2014

On Mon, 2014-05-12 at 13:32 -0400, Al Dunsmuir wrote:
> On Monday, May 12, 2014, 1:05:55 PM, Josh Boyer wrote:
> > On Mon, May 12, 2014 at 12:33 PM, Al Dunsmuir <al.dunsmuir at sympatico.ca> wrote:
> >> On Monday, May 12, 2014, 11:11:49 AM, Josh Boyer wrote:
> >>> Even if build failures were the major problem, solving those isn't
> >>> actually going to result in a working ppc32 platform.  There's little
> >>> invested in upstream software development on the platform.  The
> >>> software will bloat over time and grow beyond the resources these
> >>> machines have.  I'm certainly not trying to dissuade you from pursuing
> >>> your own interests, but asking the broader Fedora maintainer pool to
> >>> help doesn't seem appropriate.
> >>

The problem is that all the PPC32 hardware is pre V2 ISA. The 970 (G5)
and PA6T are 64-bit and V2 ISA.

Since PowerISA-2.01 (POWER4) we have added ~470 (up to the current
PowerISA-2.07 POWER8) new user mode instructions and several new
facilities (Decimal Floating Point, Vector Scalar Extended / 64
float/vector register, Hardware Transactional Memory, Event Based
Branch, Crypto, ...)

So how does keeping old PPC32 machines alive help the ecosystem, if that
community can't help exploit the latest (last 10 years) PowerISA
features?

> >> At  work,  we  don't have application-level AIX systems anymore - only
> >> virtualized systems running in LPARs on larger systems. I suspect that
> >> nearly  all of the ppc64 individual users are running on hardware that
> >> commercial users would consider to at least some degree vintage (or at
> >> least not mainstream).
> 
> > Very much no.
> 
> >> This  puts  Power  systems in an odd place between Fedora, Centos, and
> >> Redhat. It tends to limit the number of folks interested in working on
> >> Power  systems  in  general  to those with commercial interests, which
> >> means  they  may tend to be less interested in contributing to Fedora.
> 
> > On the contrary, the Fedora ppc64 efforts (more accurately POWER
> > efforts) are driven in large part by the lone commercial interest in
> > POWER today: IBM.  They have put, and are continuing to put,
> > significant resources into making sure Fedora runs well on POWER
> > platforms.
> 
> I'm  aware  of  IBM's  involvement.

Are you really?

http://openpowerfoundation.org/
http://www.enterprisetech.com/2014/04/23/ibm-google-show-power8-systems-openpower-efforts/

IBM is moving aggressively to open up and expand the POWER ecosystem.
But starting with 64-bit, Binary/Decimal Floating Point, and Vector.

> 
> I  was  an  IBMer  from  1979  to  2002, working in various roles from
> hardware  test,  test  systems  software,  mainframe debuggers and the
> C/C++  compiler  group. These days I develop a large server (low-level
> C, assembler) for RBC that runs on z/OS as well as some additional AIX
> projects.
> 
> The  problem with one vendor doing most of the work is that there does
> not  seem  to  be  effective communications - this mailing list stands
> largely unuused.
> 
> >> As  Fedora in general tends to be the incubator for new code and ideas
> >> for the other two, this may hurt the Power platform in general.
> 
> > I disagree.  The recent POWER8 open KVM announcements clearly
> > underline the value of making POWER a more open platform, and that
> > makes Fedora a great incubator for the future in those efforts.
> 
> >> I'll  agree that there is at times more affection than sanity involved
> >> with  wanting  to use or support vintage hardware.
> >>
> >> The  issue  of  supporting  vintage hardware is not isolated to ppc32.
> >> There  are  quite  a  few  folks  who  use x86 32-bit hardware who are
> >> running  into  the  same  issues in areas such as video support. There
> >> just happen to be far more users of Intel hardware than ppc (32-bit or
> >> 64-bit).
> 
> > Yes.  I believe 32-bit intel will face the same issue, though several
> > years down the road.  Intel seems to want to cling to 32-bit hardware
> > and make it even weirder (e.g. Quark) for some reason, but I suspect
> > they'll eventually stop that at some point.
> 
> >> The  intent  is not to simply use Fedora resources, but to grow skills
> >> and  experience  that  can  also  contribute to ppc64, x86 and x86_64.
> 
> > I think that is a good idea in theory.  In practice, I don't think it
> > will actually pan out that way.  The number of people that have access
> > to x86_64 machines is significantly larger than ppc32, so whatever
> > net-effect ppc32 has in growing the broader contributor base will be
> > very small.
> 
> I've  got  3 AMD and 1 Intel 64-bit systems (2 Fedora, 1 Win 7, 1 dual
> booted)  under  my desk right now. I just didn't mention those because
> they are not that noteworthy   8^).
> 
> >> Proven  packagers  don't  suddenly appear - they start contributing in
> >> their  areas  of  interest  and  over  time gain enough knowledge (and
> >> trust) to contribute to the community in a broader way.
> 
> > Yes, true.  At the same time, the existing packagers already have
> > access to things that are much more relevant to the broader Fedora
> > user base and package set.  ppc32 (and to be fair, ppc64) is something
> > many of them view as irrelevant, though they still try and fix issues
> > that come up.  It's a burden for them.
> 
> >> Until   now,   the   ppc64  maintainers  have kept the ppc32 user land
> >> operational  via  multi-arch.   They  have  also kept many of the core
> >> ppc32  core  components in good shape too.
> >>
> >> It  may  well  be more appropriate to create a remix, targeted towards
> >> this  ppc32 hardware. This remix could just be the core system, if the
> >> ppc32  userland  components  continued  to  exist  in  a  viable form.
> >> Without  that,  the  effort becomes more difficult, and the number of
> >> packages delivered drastically reduced.
> 
> > A remix for those interested would possibly be a great idea.  I think
> > several years ago Freescale had a Fedora-like/ish remix thing, but
> > it's long since been abandoned internally there and it wasn't very
> > public to begin with.
> 
> Remixes  seem  to  be  more  common these days for ARM.  I know of the
> Pidora  remix for Raspberry PI, since it is ARM6 and does not meet the
> hardware requirements for the current Fedora ARM architecture.
> 
> A remix does introduce the need to rework Fedora-branded elements, and
> adds  a  burden  of syncing to rawhide changes on a regular basis.  It
> would   be   useful   to   somehow   continue   to  use  the  existing
> infrastructure.
> 
> 
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