Intel Updates Compilers For Multicore CPUs 208
Threaded writes with news from Ars that Intel has announced major updates to its C++ and Fortran tools. The new compilers are Intel's first that are capable of doing thread-level optimization and auto-vectorization simultaneously in a single pass. "On the data parallelism side, the Intel C++ Compiler and Fortran Professional Editions both sport improved auto-vectorization features that can target Intel's new SSE4 extensions. For thread-level parallelism, the compilers support the use of Intel's Thread Building Blocks for automatic thread-level optimization that takes place simultaneously with auto-vectorization... Intel is encouraging the widespread use of its Intel Threading Tools as an interface to its multicore processors. As the company raises the core count with each generation of new products, it will get harder and harder for programmers to manage the complexity associated with all of that available parallelism. So the Thread Building Blocks are Intel's attempt to insert a stable layer of abstraction between the programmer and the processor so that code scales less painfully with the number of cores."
Anyone want to... (Score:5, Funny)
Re:Anyone want to... (Score:5, Informative)
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:)
Soooo, at the risk of sounding really stupid, wasn't this sort of thing happening with previous compilers?
Re:Anyone want to... (Score:4, Funny)
FYI, not a programmer/developer/etc., not even PHP, just interested in tech, but love the attitude anyway, AC
Re:Anyone want to... (Score:5, Informative)
They found a way to make the computer be able to determine how to use its many CPU cores automagically when you compile a program. It is cool, since it is really to figure out how to share a given workload 16 even ways.
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I can't speak for Fortran but what standard C++ mechanisms are there for threading? If they added stuff to the CLR, shouldn't it have gone through the organizations that maintain them? Weird compiler extensions are bad for cross-compatiblity. (Which I guess is the point since Intel compilers -> Intel CPUs -> No other CPU manufacturers).
Besides, threading is still an OS specific venture. Do these optimizations just work by looking for calls to fork() or the Windows alternati
Re:Anyone want to... (Score:5, Informative)
A more interesting question is "Is that good enough?" For vectorization, the answer is 'usually' - so some additional work/headaches happen when it isn't enough. For parallelization - the answer is at best 'sometimes.' So I'll get flamed two ways: (1) by people very happy with it - and say that I've understated how good it is - and it is all they need, (2) by people with programs which don't get magical auto-paralleism to solve there needs. There are more people in #2 than #1 - but this ain't a 1-size-fits-all-world. Not a bad deal if it solves you problems - otherwise - you got work to do... but that ain't the compiler's fault... parallelism requires work for most of us.
About languages...
Virtually every Fortran, C and C++ compiler these days support OpenMP, which is not part of the official standard - but is there to use. It is loop oriented, and is very Fortran-like and fits into C well enough... but is definitely not C++ like.
Fortran and C/C++ don't support threading in the language, you need to write your code to be thread-safe, and you need to use a threading package like Windows threads or POSIX threads (pthreads). Boost thread offer a portable interface to hit on the key threading needs - essentially wrappers for pthreads and Windows threads, etc. - the standards are likely to add a portable interface officially in the future. One thing Java did from the start.
Intel compilers -> Intel CPUs -> all compatible processors
The Intel compilers and libraries aim to beat other compilers and libraries regardless of the processor it is run on. No one will get it right all the time - so this is not a dare to find single examples of little code sample to prove me wrong. But if a real program doesn't get the best results from Intel - we want to know. (yeap - I work at Intel - I post for myself)
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Threading Building Blocks is a good op
Re:Anyone want to... (Score:5, Funny)
See, it's not that hard to understand.
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Re:Anyone want to... (Score:5, Interesting)
The Threading Building Blocks are yet another attempt to make writing multithreaded code easier. Frankly I don't find pthreads hard but maybe I am just odd.
Threading is very important because we are not going to see an endless increase in clock speed anymore. Intel, AMD, and IBM are all pushing multiple cores. While adding an extra core or three really does help modern systems at least a little since we are often running multiple tasks current software will not scale as well when the cores start growing in a Moore like fashion. Right now we are at four cores if Moore's law holds in two years we might see eight, then 16, then 32... As you can see it gets out of hand pretty quickly. Your average desktop will not use four cores very well much less eight until software is written to take advantage of more cores.
Yes I know that Moore said 18 months but I was going for a nice round numbers.
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Ugh ugh uhh. *Bang* Huh ugh huh mmmm uh buh ugh Fortran.
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Intel - The Software Company (Score:5, Insightful)
And as much as they develop compilers to optimize code for Intel CPUs, the code most of the time will also see a speed increase on AMD CPUs as well. Who else do you want developing a compiler but the people who made the hardware it's running on.
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You mean like nvidia making nvidia drivers for linux?
Re:Intel - The Software Company (Score:4, Funny)
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I am pretty sure that if their drivers were well made the call to OS there drivers would not be so loud.
Re:Intel - The Software Company (Score:5, Interesting)
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Anyways, it's not like MMX/SSE are really used for much of anything but benchmarks and voice synthes
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Ha! After writing software for the VIC-20 I wound up on a PET one summer and kept getting these 'out of memory' errors. I had no idea why that might be happening (had to ask the prof).
And today 'hello world' can't even fit in 20K.
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The context was student work, then in BASIC, now typically in Java. As I understand it gcj 4.2 can produce a static binary in as little as a meg.
Re:Intel - The Software Company (Score:4, Insightful)
This matters because the whole purpose of IPP is to take advantage of newer instructions. If you say "new instructions don't matter because no one uses them" it becomes a self-fulfilling prophecy. Optimized libraries could break out of that cycle, but only if they aren't used as competitive weapons.
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They should also let you build binaries without those fallback code paths, as a lot of code will never run on older machines (eg x86 macs, which all have at least sse3).
If someone's system lock up because AMD claimed to support a feature which they dont actually support, that's AMD's fault and intel could claim the moral high ground instead of the other way round.
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IIT's maths co-processor could handle matrix arithmetic directly - it didn't have a simple 1D stack, but a 2D array you could process on. It was also roughly 10x faster than the Inte
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I made a Voltron interactive-text game for it back in the day; easiest way to win quickly was just: " FORM BLAZING SWORD ".
Re:Intel - The Software Company (Score:5, Informative)
My favorite complaint: Intel checks "CPUID"
No duh - that's where the feature information is.
Next favorite: Intel checks for "GenuineIntel".
Another "no duh" - RTFM from Intel or AMD - the features flags checking has to come AFTER you determine the manufacturer AND family of the processor...
unless you don't care about running on all processors
(spare pointing out to be that you can skip the first two checks - look at the SSE flag - and it is usually right - unless say you pick just the right older processor)
We do the checks the way Intel and AMD manuals say we have to... if that is evil... so be it.
We even start by testing if the CPUID instruction exists (it didn't before Pentium processors).
Re:Intel - The Software Company (Score:4, Interesting)
It's really useful for a CPU company to develop an optimizing compiler for their hardware. It forces them to understand how their CPU features actually speed up software, and it gives them the opportunity to prove that certain hard optimizations actually work. It would probably be best for everyone if the compiler were open source, but if Intel thinks they need to sell it as a commercial product to justify it financially we still get all of the benefit on their future processor designs.
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All CPU makers make their CPUs compatible with existing compilers - but that completely ignores new instructions like SSE4. For that sort of thing, ether the programmer has to take advantage of it with hand-coded assembly, or someone needs to write a compiler optimized for the new instruction set. If the CPU vendor does it themselves rather than waiting for Microsoft and the GNU project to get around to it they can see results faster and feed information from/to hardware design more quickly and efficiently.
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They don't have to. (Score:2)
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My goodness... you can't mean... that the company which developed the hardware is in a strong position to get a few people from the hardware dev team onto the team developing software for it?! And that these people are well placed to know what's worth optimising, where and how?
No shit, Sherlock.
The only amazing thing about this is that it is such a novel insight that it is necessary for you to be modded as such.
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The only amazing thing about this is that it is such a novel insight that it is necessary for you to be modded as such.
And yet, historically it has proven to be incorrect. The usual result of getting hardware developers to write compilers is that you get shitty compilers. The amazing reason for this is that people who spend their career writing compilers turn out to be way better at it than people who spend their career developing hardware.
The Intel compiler is a notable exception - but it wasn't that long ago that code correctness was not that high on the Intel compiler's list of qualities. The code was fast, but no
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GCC (Score:3, Insightful)
Yeah, GCC is Key... (Score:2)
No and yes (Score:3, Informative)
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On the flip side... (Score:2)
It was a big source of pride for them that they got the linux kernel to build in icc without patching. *eye roll*
But they don't expect every linux user to buy ICC or anything. They position it for use for performance reasons.
Re:No and yes (Score:5, Informative)
Now, if you're Intel then you have the time and the money to work out exactly how to exploit these tradeoffs to schedule threads effectively. But you don't want to give that away for free. From the (very scanty) marketing bullshit that was linked to, it would appear that they've appear an Intel-specific threading library (probably with a POSIX interface). Separate to this is a profiling tool and a multi-threaded debugger (the latter of which is non-trivial). While any debugger will let you skip across threads allowing you do it in a deterministic manner to look for race hazards is much harder.
The analysis tools sound nice, but the bolton library is nothing special. It's purely to win a few synthetic benchmarks and gain some marketshare for ICC and therefore more "Made for Intel" applications in the market. I'm cynical about the library because what is broken about the threading model in C/C++ would take more than a library to fix. It would require redesigning the language down to the ground and choosing a different set of control constructs.
So finally, when you claim that it's because Intel has "better" coders. You don't know what you're talking about. I know a few guys who code GCC for a living, and they are grade A coders. It is because Intel has moved the goalposts. It's not so much that GCC targets multiple architectures, it's that they are trying to stick to (relatively) standard C where-as Intel is willing to redefine where the semantic gap sits if they can squeeze out a little more performance. Their attitude is screw portable code - talking across different compiler vendors here, rather than chip vendors. If what they need to squeeze into their compiler is no longer "C" strictly speaking, then they don't care. The gcc guys do.
Ah yes, and portable code can be a smaller window than you expect. That weighty 1000 page Intel document is sitting comfortable next to the AMD equivalent, which differs in suprising places.
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Gee, that makes what you have to say insightful, I guess I'll read the rest of your zzzzzzzzzzzzzzzzzzzzz
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Good grief, intel were so desperate to get someone, anyone to write code for the Itanic that I'm not at all surprised they would help the GCC guys out. They simply couldn't wait for Itanic support to trickle through at the normal rate.
Got any better examples?
learn better parallel programming techniques? (Score:3, Interesting)
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If compilers keep abstracting away the interface between the programmer and the cpu, programmers will be less likely to write better code or learn new techniques that take advantage of all the power a few extra cores can provide right?
If compilers keep abstrating away the programmer and the cpu, and getting better at optimization, programmers won't need to write better code or learn new techniques to take advantage of all the power a few extra cores can provide.
Instead the programmer can concerntrate on writing more understandable code.
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I've got a couple of thoughts that I'm not sure how to get out, so just see if can put the pieces together.
Low-level languages like C are powerful because they can interact (almost) directly with the hardware. Then there are other languages that are built on top of those languages that are designed to hide complexity and allow programmers to code more efficiently at the cost of non-optimized code.
I didn't RTFA, but if the compilers start taking liberties and "hiding the comple
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Modern processors have many features for compilers to take advantage of like pipelines and sse4 which makes the need less of being low level. Compilers do a damn good job and even jit compilers like java and
I suppose there will always be a need for low lev
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Even more so for interpreted/compiled on the fly languages. They can be dynamically compiled to take advantage of whatever hardware is available on each machine, without the developer having to code for it.
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But in career programming its all about time and making deadlines to help make your company more money.
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The people writing the compilers are "programmers" too. If the compiler programmers make the compiler do more effective optimization when turning platform-agnostic source into platform-specific binaries, that just means that burden of worrying about platform optimization is sh
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These days, a similar thing is happening with vectorization. If programmers try t
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Good programmers can write good highly optimized and mostly bug free code.
unfortunately good programmers are like good Car Drivers. Everyone says they are good, but very few really are.
Looks like something they rushed out (Score:4, Informative)
"The Intel Threading Tools automatically finds correctness and performance issues" (The tools finds?)
"Along with sufficient task scheduler and generic parallel patterns" (Who has insufficient task scheduler?)
"automatic debugger of threaded programs which detects many of thread-correctness issues such as data-races, dead-locks, threads stalls" (Sarcasm fails me...)
And that's just in the first few paragraphs, I haven't even gotten to the real meat of the article!
I'm used to informative, well-written and reasonably complete technical documentation from Intel — WTF is this?
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No, the "Intel Threading Tools" is a product, in the singular -- it finds. Maybe Intel threading tools would find, but notice the subtle difference?
OK, sso it's a bit awkward to parse, but isn't it obvious by the grammar that "sufficient" modifies both "task scheduler patterns" and "generic parallel
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Couldn't you make that sentance pretty normal sounding just by removing that one errant 'of', i.e.
"[The software includes an] automatic debugger of threaded programs, which detects many thread-correctness issues such as data-races, dead-locks, threads stalls [...]"
Altho
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Probably the source of the less than optimal text.
How's the documentation on -your- compiler coming along?
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The Intel Compiler Lab is based in two Russian cities - Moscow and Novosibirsk.
Probably the source of the less than optimal text.
The point is, whatever tortured, twisted prose was submitted should have been edited and polished before going out with an Intel logo on it. This was a white paper on the corporate web site, not a post on some random Intel engineer's blog — different standards apply.
Seriously, check out this opening paragraph from the Intel® 64 and IA-32 Architectures Application Note:
TLBs, Paging-Structure Caches, and Their Invalidation
The Intel® 64 and IA-32 architectures may accelerate the address-translation process by
caching on the processor data from the structures in memory that control that process.
Because the processor does not ensure that the data that it caches are always consistent
with the structures in memory, it is important for software developers to understand how
and when the processor may cache such data. They should also understand what actions
software can take to remove cached data that may be inconsistent and when it should do
so. The purpose of this application note is to provide software developers information about
the relevant processor operation. This application note does not comprehend task switches
and VMX transitions.
Notice how they even get the fact that "data" is plural right? That's the
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Grow up.
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develops and release an profession compiler
Too easy, moving on....
To say snide comments does not help, and shows that you have no real argument.
Um, I'm not arguing. I'm making an observation. If you diagree with me, then you're making the argument. Which is fine, just so we know where we stand. Nice non-sequitur, though.
Grow up.
So expressing dismay that a respected corporation is showing less-than-professional work is a sign of immaturity? Buy a vowel and solve the puzzle, honey, Real World moves [jargon.net] and all...
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In a post below this, I defended your original position to another poster (not that you asked me to), but here I have to say something to you. I think you're incorrectly wailing on geekoid here; I believe he is commenting on presearch's comments, not yours (check the indents). In other words, he was coming to your aid, in a way.
Take it easy.
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*sigh* I am such a dickhead...
Geekoid, I apologize. Your comment does make sense, once I pull my head our far enough that I can tell what part of the thread you're on. I owe you a $BEVERAGE. Feel free to flame me back, I deserve it.
And thanks, stuktongue, I obviously shouldn't be counted on to figure this kind of stuff out on my own...
(Damnit! I hate being a fucktard!)
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It is nice to see someone who's capable of apology, though. You don't see much humility on Slashdot, or the Internet, these days. Like the Rev. Rodney King once said, "Can't we all just get a lawn?"
I do like your use of "fucktard"... one of my favourite words. Though I prefer to use it on others.
Take it easy, man.
P.S.: I visited Intel's web site and struggled through their writeup on the threading tools. As a potential customer and user o
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WTF? No, this is SPARTA!
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"The Intel Threading Tools automatically finds correctness and performance issues" (The tools finds?)
Try italizing the product name: The Intel Threading Tools(product name) automatically finds correctness and performance issues
and it looks much better grama
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Please do not mod the writer down.
"All he/she is informing us of is his/her ignorance. There's nothing wrong with being unaware of threading concepts, but please don't suggest there's something wrong with things you just don't understand."
I think you're missing the point Doctor Memory is making. The sense I'm getting is that he isn't criticizing the technical correctness so much as the quality of the writing. He has come to expect decent writing from Intel (as have I, for that
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the product name is singular, not plural (despite the last word ending in s)
Then how do you explain the sentence "Intel® Threading Tools consist of the following:"? "Tools" is plural, and it doesn't matter how many adjectives you throw in front of it. The usual convention to make it singular is to suffix the name with a singular qualifier, like "suite" or "collection". Substituting form for content, as you suggest, isn't going to fix it.
Look at it as as function: sufficient( task scheduler and generic parallel patterns ).
It's not a function, it's a poorly-written sentence. And if you knew half as much about threading and synchronization as you pretend to,
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I can't promise we'll fire the person
I hope you don't — as I explained elsewhere, I think the content was fine, it just needed to be cleaned up before it went out, and I don't think that is the engineer's responsibility. I just hope whoever posted it to the support web site comes in tomorrow and thinks "Something's bugging me about that TBB page, I'm just going to take a quick look and make sure..." and realizes they published the original copy instead of the official version.
OK, I'll Byte (Score:3, Interesting)
As a programmer, I already have abstractions such as Active Objects [wustl.edu]. While this may make it easier for compiler writers or kernel hackers, what benefits does it bring to us ordinary mortals?
The inevitable... (Score:4, Funny)
30
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Re:The inevitable... (Score:5, Insightful)
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10
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And let it stay Goddamn dead.
It needed to be replaced 10 years ago.
I hate it, I hate it, I hate it.
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intel's product page (Score:4, Informative)
I dont understand this statement: (Score:5, Insightful)
I'm very surprised and dissapointed by the pervasiveness of the incorrect myth thats being promoted even amongst supposedly technically knowledgeable groups that:
a) Writing multithreaded code is terribly difficult
b) You need to implement code to have the same number of threads as your target hardware has cores
Both of these is completely not true at least for the PC marchitecture.
The way to develop multithreaded code is to exploit the natural parallelism of the problem itself. If the problem decomposes down most neatly into one, three or 6789 threads, then design and write the implementation that way. Consequently the complexity of the problem does not increase as the number of cores available increases.
In the PC architecture case, attempting to design your code based on the number of cores in your target hardware just leads to a twisted and therefore bad and also non-portable design.
I'm surprised how few developers seem to understand that in fact its OK, normal and often desireable to have more than one application thread running on the same core. In fact you really can't even ensure or even assume that your multi-threaded app will get one core per thread even if the hardware has enough cores, or work best if it does, as core/thread allocation is dynamically scheduled by the OS depending on loading. Not to mention there's all sorts of other apps, drivers and operating system tasks running concurrently too, so depending on each core's load, one app-thread per core may actually not be the most optimal approach anyway.
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Developers that fail to handle that will be unable to com
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Additionally, at least for "embarrassingly parallel" problems, it is easy enough to get the number of online processors at runtime, and (slightly harder) make the program use that information to decide how many worker threads to use.
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1 - If the communication or thread switching overhead exceeds the thread computation, it is not worth threading.
2 - It is (unfortunately) easy to build in "lock stepping" into otherwise independent threads. These systems scale from 1..n cores; after n cores no further scaling is seen.
3 - It *is* difficult to build correct parallel systems. Especially with points 1 and 2 in mind (and, yes, I *have* built parallel high-speed device drivers that are lock-free to avoid switching).
4 - *Proving
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Would the OS benefit from using this? (Score:4, Interesting)
As an aside, Linux is obviously compiled using GCC but I wonder if Microsoft compiles Windows using the Intel compilers?
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Why don't AMD have a compiler? (Score:2)
Seems odd to me to make the chips but not the software to allow people to fully uti
Googled (Score:2)
http://www.amd.com/epd/desiging/fusionpartners/pr
list of 3rd party software from the era of Win98/NT, just a little out of date.
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Intel compiler crippled on AMD chips!
http://www.swallowtail.org/naughty-intel.html [swallowtail.org]
Clearly it would take money and skills to have a compiler team at AMD, but that doesn't answer why they don't want to spend that money to compete with there main competitor in a vital area of their processors being the best they can be.
Re:Umm.. (Score:5, Funny)
Re:Umm.. (Score:5, Funny)
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Re:Umm.. (Score:5, Funny)
You're thinking of IBM [com.com].
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No, it means that previously, the number of transistors was doubling every 24 months and the software developer had to do nothing (or very little) to take advantage of it because the extra transistors were buying you the ability to process a single instruction stream that much faster.
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It will be interesting to see the extent to which software developers will add the necessary value to multicore processors to make them
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