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IBM Releases Compiler for Power4 and G5
davids-world.com writes "IBM offers its optimized XLC compiler not just for Intel CPUs, but also for its own G5 processor (article in German at Heise). Unlike gcc, it is optimized for the G5 and achieves a major boost in speed, as first results show. I guess we will have to compare the new benchmark data (once available) with the data we get with the optimized Intel compiler for Xeon. The compiler is available for download now."
GCC's whole purpose is to be the most portable compiler possible, not the best performing on any particular architecture.
XLC has a different set of design goals, and the internal architecture of the the compiler is different enough from GCC that there wouldn't be much point in trying to graft them together.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Type of Code G4 G5
Scalar +70% +210%
Vector +40% +70%
If this holds that places his 2.0GHz G5 (single)=254 at 787
Maybe because the optimizations require a view of the G5 that does not work with the generic view that GCC has of a processor. IBM tried to submit GCC patches but they were rejected because the GCC team did not like how deeply they affected the GCC core. GCC is THE cross platform compiler, the PPC 970 is enough different from the assumptions it makes that it will not produce optimal code without structural changes and the team doesn't want to do that.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
> It's 64bit, supports more memory physically
The 1.8 and dual 2.0 G5 machines support up to 8Gig of RAM when using 1Gig modules. How much RAM does a dual Opteron machine support?
The G5 could also run Linux, and via some emulators, Windows software as well. I think the G5s run plenty of software.
Also, it should be noted that Macs traditionally support more memory than they claim. Apple only announces the ammount you can put in with commonly available DIMM sizes, in this case 1GB.
However, the G5's documentation shows the memory interface can actually handle 16GB not just 8, so if you can get 2GB DIMMs, you will probably be able to use them.
"The worst tyrannies were the ones where a governance required its own logic on every embedded node." - Vernor Vinge
If the parent or grandparent had glanced at the PDF, they too would have noticed that GCC compatibility was one of the major points covered. There are a few pages devoted to what currently is compatible with GCC as well as what's planned. My bet is that they've had their own optimized compiler around since they first fab-ed one of these, to use for test purposes.
It would be foolish to scrap all of the work they'd already done, as well as the performance achieved (double the performance of GCC in some cases, from the PDF). There is mention of this compiler supporting SuSe Enterprise Edition however, but not enough detail to tell if it can compile SuSe or just compile *on* SuSe.
If there is a plan to integrate stuff from this compiler into GCC, my guess is that GCC compatibility would be the first step. It would be very difficult to try to integrate the two if they have fundamentally different structures and no common ground to speak of, not to mention that fact that chip manufacturers invariably keep the true capabilities of their hardware more or less secret until launch time, and putting code into GCC from the beginning may tip their hand to others before they're ready to do so.
obDisclaimer: IANACompilerGuru
I read that there is a fairly large difference between the size of a gcc compiled instruction set (100k) and the XLC compiled instruction set of the same origin (700k). Presumably they are doing some pretty impressive unrolling and inlining. I got that at this dicussion here .
That's not really true at the high end. The P4 doesn't support multi-processor configurations, and Intel charges a major price premium for Xeon chips. Dell wants ~$4000 for a dual 3 GHz Xeon with specs similar to the $3000 dual 2 GHz G5.
You could probably do a bit better building your own dual Xeon system, but it still wouldn't be cheap. You're looking at probably $1300-1500 just for the motherboard and the chips -- then add a case, RAM, a hard drive, a DVD burner, a video card, etc. and, for most potential buyers, a copy of Windows XP Pro.
This space unintentionally left unblank.
Do your homework. Apple modified the tests to reflect the actual shipping models, since they were running on prototype G5's. These issues have long been put to rest and Apple just updated their results the other day with actual shipping G5's. Get out of denial, x8 is not a religion, it's a processor for goodness sake.
Can this compiler be used to prepare glibc or any other major C libraries?
I'm sure xlc is used to compile AIX libc.
Can this compiler be used to generate native Mac OS X GUI applications (cocoa)?
No, it's not an Objective-C compiler.
Will the source be released?
No.
SIGFEH
If I go from Mac to Intel, or vice versa, and I'm not the type to pirate everything from friends, warez sources, or p2p, then I have to buy (prices from Amazon.com, rounded to nearest dollar)...
So the cost to switch is:
To Mac from Win: hardware + 1883 software
To Win from Mac: hardware + 1857 software
And that's just the basics for a good multimedia development set-up. If you code, create Flash/Shockwave, etc., then you can add on another $500-1000 for other tools... or more.
Bundles and other incentives can bring it down, but this is not an inconsequential cost. Even if you could get a 10% faster PC for the same price as a Mac, or a 10% faster Mac for the same price as a PC, you have to ask yourself how much that 10% is really worth to you.
How often will you utilize all the capabilities of the machine and stretch the system past the capabilities of the alternative? How many hours of labor will the system save you over time?
And when all is said and done, you can scream over benchmarks and which is the better OS all you like. But they're totally meaningless.
(Mac fans can claim Windows has an inherently higher TCO, but let's face it, that's if the user is someone who thinks GNU is a Milton Bradley game that succeeded Gnip-Gnop. The rest of us know that a well-educated Windows user can avoid many of its pitfalls.)
Each time I've upgraded my hardware, there's one question I ask when I consider whether to switch platforms... What's the bottom line? How much more would this cost or save?
When I worked it out in 1993, a 486 DX2/50 by mail-order beat an education priced Quadra 40 from the university. Since then, I've invested much more in software that I had as a student... Even though the hardware costs are becoming less of a factor, the software costs have become more of a factor to compensate.
If I won the lottery, I'd buy a Mac and all the cool software I wanted. But barring that, I'll be looking carefully at Prescott versus Athlon 64 in the coming months, and making my choice in the Wintel world because that's where my software is.
So, though this compiler news is cool if you're a Mac User, because it makes your platform better *for you*, the arguments about whether Mac beats WinTel are a lot of sound and fury, signifying nothing.
Start a happiness pandemic