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Red Hat To Support PowerPC, AltiVec
Steve Cowan writes "According to an article at MacCentral, Red Hat has announced that they will produce a GNUPro toolchain and cross compiler for AltiVec-enabled PowerPC processors (such as that found in the Power Mac G4).
It will be interesting to see just what kind of performance gains this will bring, because many believe that the full potential of AltiVec is far from tapped."
As to the question of "what will this bring since altivec is underused/underappreciated?" the answer is simple: nothing.
The same problem remains: if you want to optimize your algorithm using Altivec, you still have to jump through some hoops. GCC isn't magically going to detect that your for loop could be done 400 times faster using Altivec: you'll need to tell it.
In short, you can do everything you need to already using the existing tools from here.
Just-another-tool does not news make.
RedHat's GNUPro (the old cygnus stuff) is what's being touted ... that'd be the compiler and tool chain.
This is not a new redhat Linux distro.
BTW, GCC and binutils already support the AltiVec, including the C extensions.
Motorola and IBM parted ways at the G4. The Power4 doesn't include AltiVec....IBM wanted to use the on-chip real estate for other things.
Also, the Power4 is a 64bit chip, and the G4 is still 32bit.
- Sig
If Red Hat manages to develop a really good implementation of their AltiVec libraries, it could have rather far-reaching effects in the advancement of Linux onto the desktop. For example, in the current Macintosh community, a staple of the software collection is Adobe Photoshop. There is a good relationship between Mac users and the program, as well as what seems to be a good relationship between Adobe and Apple. This relationship can be seen when one takes into consideration the fact that Photoshop always runs faster on Mac hardware than on PC (that's why the Apple demos are always focused around Photoshop), and the new versions always come out for Mac first.
If Red Hat can build a version of Linux specifically designed to run on a G4-powered AltiVec machine, and do at least as good a job of it as Apple has done with OS X, Adobe may well port Photoshop to that version of Linux. And if the users can get their Photoshop needs fulfilled, they may not necessarily care what OS they are running, and (let's presume that they are at work), if they can get Photoshop to run faster with this newfangled thing called "Red Hat," they may just give it a shot. This will lead to people learning Linux and possibly use it at home.
And, if Adobe does port Photoshop to AltiVec Red Hat, that is just a couple of steps away from porting it to Linux in general, which would of course be a bonus to the community as a whole. The Gimp may be acceptable, it may even be good, but it is no Photoshop.
Of course, this is only one example, and many other good things may well come of this.
Lack of eloquence does not denote lack of intelligence, though they often coincide.
The RS/6000's use the PPC 604 chip, if memory serves correctly, which has no AltiVec unit. There would probably be no performance gain over the AIX compiler that was built specifically for that chip.
Karma: Ran over your dogma.
You can find out more about Altivec here. Support by Redhat has been talked about before on the mailing list, with some RH developers jumping in at points.
Altivec does short parallel vector crunching by adding some 128bit registers for you to play with and SIMD operations to crunch a bunch of numbers in them. Where I work we use Altivec to optimize matrix operations and it does its job well. Neat stuff, even though I'm not an assembly man myself.
Actually given the partnership between IBM and redhat I do expect a PPC version of RH sometime soon. At LWCE they had SUSE running on Rs6000 and said they had a preview running on the new p690 machines. I would not expect RH to leave the PPC hardware all to SUSE when they made a version of 390.
Government is the abdication of your responsibility to a faceless bureaucracy. Anarchy(absence of government)is the a
I dunno, check out the Altivec Forum and the Scitech List, people writing in C seeing large performance improvements.
From what I understand, the RC-5 and SETI apps are C with pre-compiler directives. The RC-5 G4 client blows throws keys 16 times faster than a same-speed P4.
Lies about crimes
I'm glad to see someone with some sense comment on this rather than fly off with yet another OS X versus Linux rant.
Note that the post indicated that they are adding cross-compiler support to their GnuPro tool chain. The main target of this tool is embedded people (which is why you would want a cross compiler).
Regarding the comments about Apple extensions to GCC regarding Altivec, it is likely that what Cygnus/Red Hat is doing is folding in those very changes.
All of you web surfer, word processor, gimp'in, rippin' and burnin' (i.e. desktop apps) types out there need to remember that the PowerPC is heavily used in the embedded industry.
The reason it is used so much is the very reason why Apple could make the cute Cube. They run very low wattage (and, thus, heat) for their relative power. There are many application areas where a chip that must have 35+ dBA cooling just to keep from frying itself is just not acceptable.
One should note that the power and heat characteristics of the x86 line are so poor that Intel doesn't really attempt to compete using them in the embedded market. For this, they eviscerated DEC in order to kill the Alpha and gain the StrongArm as their embedded offering.
One person mentioned that compilers have difficulty automatically extracting parallelism. They are correct. However, the embedded arena is one of those areas where people will regularly hand-optimize critical sections of code in order to meet performance or economic goals.
Desktop users must remember that embedded processors outweigh workstation processors by many orders of magnitude. This is big business, and the code involved is very interesting. However, your brand new car is not as obvious of a computing platform as your brand new laptop.
Okay, I've expelled enough air for now. Later...
The G3/G4, Power4 etc. belong to the PowerPC (PPC) family of CPUs. Of course, we all know this.
However, few participating in the discussion seem to acknowledge, that there is more systems running PPC than Apple's Macs.
PPC is important in the embedded market. It has a high performance, stays relatively cool There are 'computers on a card' (a PCI card with a G3/G4 on it plus memory). They communicate over TCP/IP (or proprietary protocols) over the PCI bus with the host system. Nice if you want to have a mini cluster, a physical firewall, or whatever...
Then we have several (Micro)ATX mobos, some even for dual G4 (SMP). They get used mostly in the industry, however, this year will see two new home/office-desktop G3/G4 systems that have nothing in common with Apple. See here:
So it is obvious that RedHat, being focussed more on industry/server markets than on hte Desktop (that is their current goal as far as I am informed) has some interest in supporting PPC development. Altivec is a very good instruction set and having optimizations for it will be a great benefit. Altivec is not only for MultiMedia, btw. !
Theoretically, all these systems could run LinuxPPC !
Personally I am happy to see some major resource supporting the PowerPC since I would prefer a PPC machine far more than the archaical, outlived, patched & hacked i86 platform (can you use all your PCI slots without clashes...? I can't and my MoBo is from April last year...) Also the PPCs keep quite cool, meaning one could live without an active fan, unlike the Athlon hair-driers...;-)
For the enhusiasts: There are at least two other desktop (!) OS in the works, which are PPC native and come with SMP support: MorphOS (in the works since three years or more) and AmigaOS4.x
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