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The Potential of Science With the Cell Processor

Zonk posted more than 8 years ago | from the making-a-station-play dept.

176

prostoalex writes "High Performance Computing Newswire is running an article on a paper by computer scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory. They have evaluated the processor's performance in running several scientific application kernels, then compared this performance against other processor architectures. The full paper is available from Computer Science department at Berkeley."

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Cell + Linux = success (3, Funny)

Anonymous Coward | more than 8 years ago | (#15419879)

OS X is closed source. This means that it is the work of the devil - its purpose is to make the end users eat babies.

Linux is the only free OS. Yes the BSD lincenses may appear more free, but as they have no restrictions, they are actually less free than the GPL. You see, restricting the end user more actually makes them more free than not putting restrictions on them. You must be a dumb luser for not understanding this.

And you obviously dont have a real job. A real job involves being a student or professional academic. You see, academics are the ones who know all about productivity - if you work for a commercial organisation you obviously do not know anything about computers. Usability is stupid. Whats wrong with the command line? If you cant use the command line then you shouldnt be using a computer. vi should be the standard word processor - you are such a luser if you want to use Word. Installing software should have to involve recompiling the kernel of the OS. If you dont know how to do this, you are a stupid luser who should RTFM. Or go to a Linux irc channel or newsgroup. After all, they are soooo friendly. If you dont know how the latest 2.6 kernel scheduling algorithm works then they will tell you to stop wasting their time, but they really are quite supportive.

Oh, and M$ is just as evil as Apple. Take LookOUT for instance. You could just as easily use Eudora. Who needs groupware anyway, a simple email client should be all we use (thats all we use as academics, why cant businesses be any different).

And trend setters - Linux is the trend setter. It may appear KDE is a ripoff from XP, but thats because M$ stole the KDE code. We all know they have GPL'ed code hidden in there somewhere (but not the things that dont work, only the things that work could possibly have GPL'ed code in it).

And Apple is the suxor because they charge people for their product. We all know that its a much better business model to give all your products away for free. If you charge for anything, then you are allied with M$ and will burn in hell.

PS3 will rule in 2008 (-1, Offtopic)

Gax (196168) | more than 8 years ago | (#15419881)

The Cell processor is interesting. Nintendo may dominate the 2006/7 market with cheap hardware, but the PS3 will gradually gain dominance as the price drops and people learn how to write for it.

Re:PS3 will rule in 2008 (0, Offtopic)

Watson Ladd (955755) | more than 8 years ago | (#15419886)

No. I think the PS3 will not have a large price drop until after the market is largely staturated. Enough about consoles!

Re:PS3 will rule in 2008 (-1, Offtopic)

CastrTroy (595695) | more than 8 years ago | (#15419902)

The problem with the PS3 will be that it will take companies a lot of time and money to develop games for it. They won't do this until they know there will be enough consumers to buy their games. The consumers on the other hand, won't buy it unless there are good games for it. Kind of a catch 22 if you ask me. Nintendo's model on the other hand, is to make it really cheap and easy to design games for the Wii, so there isn't so much risk involved for the developers. There also isn't so much risk for the consumers, because the system itself is so much cheaper than the competition.

PS3 will RULZ! in 2008 (0)

Anonymous Coward | more than 8 years ago | (#15419946)

"The problem with the PS3 will be that it will take companies a lot of time and money to develop games for it. They won't do this until they know there will be enough consumers to buy their games. The consumers on the other hand, won't buy it unless there are good games for it. Kind of a catch 22 if you ask me."

The phrase you're looking for is "development tools".

"Nintendo's model on the other hand, is to make it really cheap and easy to design games for the Wii, so there isn't so much risk involved for the developers. There also isn't so much risk for the consumers, because the system itself is so much cheaper than the competition."

That depends on the cost of development systems. Also something you have forgotten. The platforms aren't just differentiated by hardware, but by genre.

Re:PS3 will rule in 2008 (0, Offtopic)

FatherOfONe (515801) | more than 8 years ago | (#15419961)

Do you honestly believe that Sony won't sell all 6 million consoles at launch time?

Now the next question. Do you believe that they won't sell 20 million by the 2007 Christmas?

That is a huge install base. Remember that Sony at any time can lower the price of the PS3. If price ever truely becomes an issue, then they can adjust it. They will keep it as high as possible as long as possible.

Now on the other hand, it will probably never reach the price of the Nintendo, but then the Nintendo doesn't have HD, Blu-Ray or a hard drive. Those three options add cost, but will probably add significant value to a lot of games.

The way I see the console going is that Sony will dominate the 12 year old and up crowd. Microsoft will own a smaller percentage this time than with the XBOX, and Nintendo will own (as always) the 12 and under crowd.

Now what will the average slashdot/digg reader buy? Well those people generally hate Sony and Microsoft, but at the end of the day, they will buy the console with the best games they like. That will be Sony, and then I could see some of the Slashdot crowd actually tinkering with Linux on the PS3.

I am also curious to see what happens when the development kits get better for both the 360 and PS3. Creating an "easier" way to use the multi cores in those system will show the differences between all the consoles even more, and also display better how well (or poorly) the PS3 runs normal Linux stuff.

The last part of the puzzle is how cheap 1080P TV's will get in the next 5 years. It isn't out of the question to hook up a keyboard, mouse and "cheap" 1080P LCD or Plasma TV to a PS3 and have a computer. This is a giant leap forward for consoles, and Sonys first attempt to bridge the gap between console, computer and DVR type of device.

Time will tell if it will be a sucess or not, but one thing is certain. They will sell all the systems they can make this year and early next. People are asking every day now at EB if they can preorder the system. "If" Sony could make 20 million this year they would sell every one. I kind of wonder why they honestly don't raise the price up even more. It would suck for us gamers, but if I had a product that would max out my manufacturing for the next two years and I was sure I would sell every one I would make, then I would probably rethink my asking price. The only logic I see is that they don't want to anger the initial buyers if they have to lower the price next year for the second wave buyers. If I was Microsoft I would be very worried about the PS3. If I was Nintendo I would keep producing kids games and doing pretty much what they are doing, much like they did with the GameCube, the only difference is that I would try not to over "Mario" the system.

Re:PS3 will rule in 2008 (0, Offtopic)

Lonewolf666 (259450) | more than 8 years ago | (#15420021)

The last part of the puzzle is how cheap 1080P TV's will get in the next 5 years. It isn't out of the question to hook up a keyboard, mouse and "cheap" 1080P LCD or Plasma TV to a PS3 and have a computer. This is a giant leap forward for consoles, and Sonys first attempt to bridge the gap between console, computer and DVR type of device.
If this is worthwile for users will depend a lot on how open the console is for third-party software. Usually consoles are designed to run only software licensed by the console vendor, and in some cases those vendors will even sue companies that offer modifications. An example where Microsoft went after XBox modders:
http://www.geek.com/news/geeknews/2002Oct/gam20021 004016641.htm [geek.com]

If Sony pulls a similar thing with the PS3, it will remain rather uninteresting as a computer unless they provide all the software an average user might want. Which I don't believe ;-)

No, it won't (0, Offtopic)

PackerX (727195) | more than 8 years ago | (#15420028)

I'm going to disagree with you here. Here's my game system buying guide:

-I'll buy a DS Lite the day it comes out. There are several games I like and several more coming.

-I'll buy an XBox 360 when Splinter Cell comes out.

-I'll buy a PS2 as soon as I decide I can't go without playing Guitar Hero any longer.

-I'll pre-order a Wii (provided Twilight Princess remains a launch title)

-I do not see myself ever purchasing a PS3.

Each system offers me something. The DS gives me portability and a growing library of games, including some real gems. The XBox 360 gives me Live, wireless controllers, and games that I would like to play: Oblivion, Fight Night Round 3, etc. Wii is my only 'must-have' system. A low price, innovation, a lot of developer support, and established exclusive franchises. Not to mention the ability to play tons of SNES, NES, and Sega games. PS3 offers me... nothing. The only thing that would possibly entice me is the number of RPG's traditionally available on the PS systems, but I never bought a PS2 and the price was MUCH lower. Final Fantasy isn't worth $700 to me.

Every discussion I have had regarding consoles has ended the same way. People who don't have a 360 yet plan on getting one within the year, everyone wants the Wii, and the PS3 gets a big, "So what?"

The PS3 may have the hardware advantage, but that's all it offers. From a gaming perspective, Sony has yet to give me one good reason to spend my money on a console with technology that won't be fully utilized until about two years after release, a video disc format that won't be widespread until at least a year after release (if ever), and HD (which I don't have).

At least the scientists are getting something out of it. Now if Sony gave me a system that could do complex COMSOL models, I'd be interested.

Re:No, it won't (0)

Anonymous Coward | more than 8 years ago | (#15420335)

So, you're going to wait for Splinter Cell before you buy Xbox 360? Well, the two million Japanese gamers alone who are Metal Gear fans are going to buy the PS3 when Metal Gear Solid 4 comes out. The three million American gamers who are Metal Gear fans are going to buy PS3 when MGS4 comes out. That adds up to five million easy sales for PS3 and you're not even taking Europe into account yet. Don't think Metal Gear is popular in Europe? If so, then how would you care to explain the "European Extreme" difficulty mode in MGS3: Subsistence? And that's just the Metal Gear franchise. You've still got Final Fantasy to chalk up the tally in Japan and North America. Want to bet that more people will buy PS3s when FFXIII comes out than people will buy Xbox 360 when Splinter Cell comes out? Last I checked, Splinter Cell was nothing more than a Metal Gear rip-off masquerading as a "highly intellectual thriller". I'd rather go with Kojima's genuine article.

Re:PS3 will rule in 2008 (0, Offtopic)

nayten (965463) | more than 8 years ago | (#15420257)

Your rant is juvenile. Check the facts-- not everyone who owns a nintendo is under 12. I didn't realise owning a game system that has more first-party titles than bloody, violent, car-robbing games and shitty budget titles constituted the age group for the console, but I digress. Your fuzzy statement of having BR, HD-DVD, and a HD doesn't offer much either. The 3D0 launched as one of the first 32-bit CD-based systems and it didn't help them. Also remember that the system launched at $799-- only $100 more than the PS3 is scheduled to. And whats up with this thing about buying these massive HDTVs? Most of us still have our good old standard television sets. Partially due to the price to upgrade, but also since it just doesn't do anything special. I highly doubt most people are looking forward to dump $700 on a new game console, then $2000 months later for a new tv to play UT2007 with. I could be wrong, though. (sarcasm) You also forget, that Nintendo is the only major console maker who doesn't LOSE money by loading up their consoles with bells and whistles, like hard drives and HD output. They also put out plenty of first-party titles. They're also the ones generating the most revenue off their products, based off what they put in. And that they should-- they've been in the business for over twenty years now. What it comes down to is, the gamers care about the games. Nintendo had plenty to deliver at E3, while Sony didn't. You really sound young, making all of these statements about console hardware. That's exactly the reason why rehashed shooter crap overflows my gaming magazines today.

Re:PS3 will rule in 2008 (0, Offtopic)

Xymor (943922) | more than 8 years ago | (#15420492)

lso remember that the system launched at $799-- only $100 more than the PS3 is scheduled to
according to Google: $799 - $599 = $200 [google.com]

Re:PS3 will rule in 2008 (1)

traveller604 (961720) | more than 8 years ago | (#15419960)

I disagree. Next generation isn't about graphics as much as it's about revolutionizing the way we play. Nintendo is the only one who understands this. Wii will rock you.

What about the compiler? (2, Insightful)

Watson Ladd (955755) | more than 8 years ago | (#15419901)

The paper did a lot of hand-optimization, which is irrelevent to most programmers. What gcc -O3 does is way more importent then what an assembly wizard can do for most projects.

What about the programmer? (5, Insightful)

Anonymous Coward | more than 8 years ago | (#15419919)

"The paper did a lot of hand-optimization, which is irrelevent to most programmers. "

But not to programmers who do science.

"What gcc -O3 does is way more importent then what an assembly wizard can do for most projects."

Not an unsurmountable problem.

Re:What about the compiler? (5, Insightful)

Anonymous Coward | more than 8 years ago | (#15419925)

Hand optimization _is_ relevant to scientific programmers

Re:What about the compiler? (2, Insightful)

penguin-collective (932038) | more than 8 years ago | (#15420340)

Except for a tiny minority of specialists, most scientific programmers, even those working on large-scale problems, have neither the time nor the expertise to hand-optimize. Many of them don't even know how to use optimized library routines properly.

Re:What about the compiler? (5, Insightful)

TommyBear (317561) | more than 8 years ago | (#15419945)

Hand optimizing code is what I do as a game developer and I can assure you that it is very relevant to my job.

Re:What about the compiler? (1)

C.A. Nony Mouse (860026) | more than 8 years ago | (#15420008)

That games can be written to run well on Cell is not news. That the same might be true for scientific code is.

Re:What about the compiler? (1, Insightful)

Anonymous Coward | more than 8 years ago | (#15420284)

Methinks that the point was that if a GAME development company is going to fork over the cash for ASM wizards, a company spending a few hundred mil. building a super-computer might just consider doing the same. Maybe.

And I know from Uni that many profs WILL hand optimize code for complex, much used algorithms. Then again, some will just use matlab.

Re:What about the compiler? (1)

SeeMyNuts! (955740) | more than 8 years ago | (#15420826)

"a company spending a few hundred mil. building a super-computer might just consider doing the same"

Well, if they hire the typical contractor to do the work, $10 million goes towards the computer, $90 million goes towards a coffee service, and $300 million goes towards per diem.

Re:What about the compiler? (0)

Anonymous Coward | more than 8 years ago | (#15420118)

However, virtually no scientific programmers do hand optimization of assembly, even for giant programs running on big clusters. So that's irrelevant to resolving the question of whether the Cell is suitable for scientific programming.

Re:What about the compiler? (1)

Shinobi (19308) | more than 8 years ago | (#15420789)

Well, that's where you're wrong. There are more people who hand-optimize than the academic world cares to admit, since admitting it would also mean admitting that the oh-so-sacred academic practices as well as compiler technology+libraries has some areas where they can't be applied efficiently.

Re:What about the compiler? (3, Informative)

JanneM (7445) | more than 8 years ago | (#15420285)

Hand optimizing code is what I do as a game developer and I can assure you that it is very relevant to my job.

It makes sense for a game developer - and even more an embedded developer. You spend the time to optimize once, and then the code is run on hundreds of thousands or millions of sites, over years. The time you spend can effectively be amortized over all those customers.

For scientific software the calculation generally changes. You write code, and that code is typically used in one single place (the lab where the code was written), and only run a comparatively few times, indeed sometimes only once.

For a game developer to spend three months extra to shave a few seconds of one run of a piece of code makes perfect sense. For an embedded developer using a couple of months' worth of development cost to be able to use a slower, cheaper chip, shaving a dollar of the production of perhaps tens of millions of gadgets makes sense.

For a graduate student (cheap as they are in the funny-mirror economics of science) to spend three months to make one single run of a piece of software run a few hours faster does not make sense at all.

In fact, disregarding the inherent coolness factor of custom hardware, in most situations it just doesn't pay to make custom stuff for science when you can just run it for a little longer to get the same result. In fact, not infrequently have I heard about labs spending the time and effort to make custom stuff, but by the time they're done, the off the shelf hardware had already caught up.

Re:What about the compiler? (0)

Anonymous Coward | more than 8 years ago | (#15420706)

I was once working on data analysis involving an entire year of data. The algorithm we were using was weighted least squares, which is O(n^2). The data analysis would have taken a few weeks if it weren't for some clever optimisations. So I don't think the time I spent on that is wasted time.

Re:What about the compiler? (1)

JanneM (7445) | more than 8 years ago | (#15420776)

The data analysis would have taken a few weeks if it weren't for some clever optimisations. So I don't think the time I spent on that is wasted time.

It's not wasted time if the time spent optimizing is less than the time saved. So for your example, assuming it wasn't algorithmic optimizations (which are orthogonal to doing funky assembler stuff), you may save a few days on a few weeks running time. So if the optimization took a couple of days of coding it may have been worth it. Otherwise it was not.

And for scientific apps especially, you really do have to factor in the added cost of tweaking the software - you _always_ need to tweak, often over many cycles - when part of it is as opaque and difficult to understand as assembly optimizations are (which often implies explicit use of the semi-parallel features of modern CPU_s today).

Re:What about the compiler? (2, Interesting)

suv4x4 (956391) | more than 8 years ago | (#15419971)

The paper did a lot of hand-optimization, which is irrelevent to most programmers. What gcc -O3 does is way more importent then what an assembly wizard can do for most projects.

Actually bullshit. We're talking scientific applications here, and it's not uncommon that programs written to run on supercomputers *are* optimized by an assembly wizard to squeeze every cycle out of it.

Re:What about the compiler? (1)

Watson Ladd (955755) | more than 8 years ago | (#15420149)

Most projects, not some superexpensive code. Sure, fast API's like BLAS will use hand-written asembler, but it takes a compiler to find those optimizations that are too complex to do by hand or hard to find while being easy to do. And the asembler advantage is negative on some RISC processors now due to advances in compiler design. So gcc -O3 might outpreform asm, so then gcc -O3 is relevant as nobody will want to use asm as gcc can outpreform it. But I haven't seen anything about how true this is for the Cell.

Re:What about the compiler? (3, Informative)

adam31 (817930) | more than 8 years ago | (#15420807)

Actually bullshit.

Actually, it's not bullshit. Simple C intrinsics code is the way to go to program the Cell... there's just no need for hand-optimized asm. Intrinsics has a poor rep on x86 because SSE sucks. 8 registers. A source operand must be modified on each instr, no MADD, MSUB, etc.

But Cell has 128 registers and a full set of vector instructions. There's no danger of stack spills. As long as the compiler doesn't freak out about aliasing (which is easy), and it can inline everything, and you present it enough independent execution streams at once... the SPE compiler writes really, really nice code.

The thing that does need to be hand-optimized still is the memory transfer. DMA can be overlapped with execution, but it has to be done explicitly. In fact, algorithms typically need to be designed from the start so that accesses are predictable and coherent and fit within ~180kb. (Generally, someone seeking performance would do this step long before asm code on any platform anyway...)

Re:What about the compiler? (1)

maximthemagnificent (847709) | more than 8 years ago | (#15419983)

Hard science is exactly the sort of application that would employ an assembly programmer to optimize code.

Re:What about the compiler? (0)

Anonymous Coward | more than 8 years ago | (#15419986)

Did you RTFA? "Most" programmers aren't doing High Performance Computing (HPC).

Re:What about the compiler? (2, Informative)

Anonymous Coward | more than 8 years ago | (#15420063)

Insightful? Ah... no.

Scientific users code to the bleeding edge. You give them hardware that blows their hair back and they will figure out how to use it. You give them crappy painful hardware (Maspar, CM*) that is hard to optimize for, then they probably won't use it.

Assembly language optimization is not a big deal. Right now the biggest thing bugging me is that I have to rewrite a core portion of a code to use SSE, since SSE is so limited for integer support. As this is a small amount of work, and the potential gains are so large (about 4x), it doesn't make sense not to do this. Some of it will be hand coded and optimized assembler. This is how we have to program. Scientists need the fastest possible cycles, and as many of them as possible ... at least the ones I know need this. There are a few who do all their analysis on Excel spreadsheets. They don't need much in the way of speed. The rest of us do.

Re:What about the compiler? (1)

Gromius (677157) | more than 8 years ago | (#15420676)

I'm a particle physicist. Our computing needs are insane but massively parrallel, basically the grid is being developed for us and us alone although we figure that some other people might find a use for it. We spend the fast majority of our day to day job programming. And we're, with only a few exceptions, piss poor at it. Forget hand optimized assembly, I'm currently fighting a losing battle to stop people using x = pow(y,2) (and I have found that in our base software package, one suposedly written by the experts). However the solution usually is just to buy a faster machine to run it on.

Re:What about the compiler? (1)

statusbar (314703) | more than 8 years ago | (#15420724)

Jeez, that reminds me of the "Database Specialists" doing "SELECT * from mytable;" and then doing a java for() loop to find the rows they are interested in.. Then they complain about the database machine being too slow so they get it upgraded.

How much do these new machines cost?

How much does a competent programmer cost?

Which one is the best option?

--jeffk++

Re:What about the compiler? (0)

Anonymous Coward | more than 8 years ago | (#15420116)

What gcc -O3 does is way more importent then what an assembly wizard can do for most projects.


For a word processor? You are right.

For a scientific library? No, you are dead wrong.

This particualar article was about scientific number crunching, no?

Re:What about the compiler? (5, Insightful)

samkass (174571) | more than 8 years ago | (#15420280)

What seems to be more important than that is:

"According to the authors, the current implementation of Cell is most often noted for its extremely high performance single-precision (32-bit) floating performance, but the majority of scientific applications require double precision (64-bit). Although Cell's peak double precision performance is still impressive relative to its commodity peers (eight SPEs at 3.2GHz = 14.6 Gflop/s), the group quantified how modest hardware changes, which they named Cell+, could improve double precision performance."

So the Cell is great because there's going to be millions of them sold in PS3's so they'll be cheap. But it's only really great if a new custom variant is built. Sounds kind of contradictory.

Re:What about the compiler? (2, Informative)

FromWithin (627720) | more than 8 years ago | (#15420435)

So the Cell is great because there's going to be millions of them sold in PS3's so they'll be cheap. But it's only really great if a new custom variant is built. Sounds kind of contradictory.

Did you not read the last bit?

On average, Cell is eight times faster and at least eight times more power efficient than current Opteron and Itanium processors, despite the fact that Cell's peak double precision performance is fourteen times slower than its peak single precision performance. If Cell were to include at least one fully utilizable pipelined double precision floating point unit, as proposed in their Cell+ implementation, these speedups would easily double.

So it's really great already. If it was tweaked a bit, it would be ludicrously great.

Re:What about the compiler? (2, Interesting)

cfan (599825) | more than 8 years ago | (#15420516)

>So the Cell is great because there's going to be millions of them sold in >PS3's so they'll be cheap. But it's only really great if a new
>custom variant is built. Sounds kind of contradictory.

No, the Cell is great because, as the pdf shows, it has an incredible Gflops/Power ratio, even in its current configuration.

For example, here are the Gflops (double precision) obtained in 2d FFT:

      Cell+ Cell X1E AMD64 IA64

1K^2 15.9 6.6 6.99 1.19 0.52
2K^2 26.5 6.7 7.10 0.19 0.11

So a single, normal, Cell can be compared with the processor of a Cray (that uses 3 times more power and costs a lot more).

Re:What about the compiler? (1)

Angstroman (747480) | more than 8 years ago | (#15420572)

So the Cell is great because there's going to be millions of them sold in PS3's so they'll be cheap. But it's only really great if a new custom variant is built. Sounds kind of contradictory.

The HPC world is substantially different from either gaming or "normal" application programming. The strong draw of the cell is that it is a production core with characteristics that are important to High Performance Computing, particularly power dissipation per flop. While conventional applications target getting the most out of a processor, HPC applications center on scalability in number of processors. This means running the largest number of processors for a given power/cooling supply, and maintaining the lowest latency in interprocessor communication. The latter is closely related to the physical layout of the processor array, which is also dependent upon cooling strategy. Hand coding, or at least hand optimization of the code, is reasonable for these applications. The resulting improvement can make possible calculations that would otherwise not be accomplished. As the number of processors increases substantially, the leading issue shifts from local execution speed to load balancing. Load balancing requires at least an initial "hand code" for a given architecture in any event.

There are several application spaces for HPC. Some, like semantic network processing do not require double precision and can be mounted on cell processors as they stand. Those which are fundamentally based on massive differential equation solution would benefit from the double precision modification. The key point here is that the double precision pipeline unit is a modification, not a different core. It is likely that IBM can make such a change at a fraction of the cost of the original core development with benefits not only to the HPC community, but also to potential workstation use.

The bottom line is than one can be easily mislead trying to think of HPC architectures and programming from the familiar standpoint of game and web server development.

Re:What about the compiler? (0)

Anonymous Coward | more than 8 years ago | (#15420729)

It really seemed they were just talking about processor evolution. While they found the Cell to be good they saw room for improvement. They called their ideas Cell+. That's not really contradictory.

Re:What about the compiler? (4, Interesting)

john.r.strohm (586791) | more than 8 years ago | (#15420522)

Irrelevant to most C/C++ code wallahs doing yet another Web app, perhaps.

Irrelevant to people doing serious high-performance computing, not hardly.

I am currently doing embedded audio digital signal processing, On one of the algorithms I am doing, even with maximum optimization for speed, the C/C++ compiler generated about 12 instructions per data point, where I, an experienced assembly language programmer (although having no previous experience with this particular processor) did it in 4 instructions per point. That's a factor of 3 speedup for that algorithm. Considering that we are still running at high CPU utilization (pushing 90%), and taking into account the fact that we can't go to a faster processor because we can't handle the additional heat dissipation in this system, I'll take it.

I have another algorithm in this system. Written in C, it is taking about 13% of my timeline. I am seriously considering an assembly language rewrite, to see if I can improve that. The C implementation as it stands is correct, straightforward, and clean, but the compiler can only do so much.

In a previous incarnation, I was doing real-time video image processing on a TI 320C80. We were typically processing 256x256 frames at 60 Hz. That's a little under four million pixels per second. The C compiler for that beast was HOPELESS as far as generating optimal code for the image processing kernels. It was hand-tuned assembly language or nothing. (And yes, that experience was absolutely priceless when I landed on my current job.)

Re:What about the compiler? (0)

Anonymous Coward | more than 8 years ago | (#15420537)

In a previous incarnation, I was doing real-time video image processing on a TI 320C80. We were typically processing 256x256 frames at 60 Hz. That's a little under four million pixels per second. The C compiler for that beast was HOPELESS as far as generating optimal code for the image processing kernels. It was hand-tuned assembly language or nothing. (And yes, that experience was absolutely priceless when I landed on my current job.) Ahh, the wonders of Code Composer Studio. :)

No, this is why we have subroutine libraries (5, Interesting)

golodh (893453) | more than 8 years ago | (#15420527)

Although I agree with your point that crafting optimised assembly language routines is way beyond most users (and indeed a waste of time for all but an expert) there are certain "standard operations" that

(a) lend themselves extremely well to optimisation

(b) lend themselves extremely well to incorporation in subroutine libraries

(c) tend to isolate the most compute-intensive low-level operations used in scientific computation

SGEMM

If you read the article, you will find (among others) a reference to a operation called "SGEMM". This stands for Single precision General Matrix Multiplication. This is the sort of routines that make up the BLAS library (Basic Linear Algebra Subprograms) (see e.g. http://www.netlib.org/blas/ [netlib.org] ). High performance computation typically starts with creating optimised implementation of the BLAS routines (if necessary handcoded at assembler level), sparse-matrix equivalents of them, Fast Fourier routines, and the LAPACK library.

ATLAS

There is a general movement away from optimised assembly language coding for the BLAS, as embodied in the ATLAS software package (Automatically Tuned Linear Algebra Software; see e.g. http://math-atlas.sourceforge.net/ [sourceforge.net] ). The ATLAS package provides the BLAS routines but produces fairly optimal code on any machine using nothing but ordinary compilers. How? If you run a makefile for the ATLAS package, it may take about 12 hours (depending on your computer of course; this is a typical number for a PC) or so to compile. In this time the makefile will simply run through multiple switches and for the BLAS routines and run testsuites for all its routines for varying problem sizes. And then it picks the best possible combination of switches for each routine and each problem size for the machine architecture on which it's being run. In particular it takes account of the size of caches. That's why it produces much faster subroutine libraries than those produced by simply compiling e.g. the BLAS routines with an -O3 optimisation switch thrown in.

Specially tuned versus automatic?: MATLAB

The question is of course: who wins? Specially tuned code or automatic optimisation? This can be illustrated with the example of the well-known MATLAB package. Perhaps you have used MATLAB on PC's, and wondered why its matrix and vector operations are so fast? That's because for Intel and AMD processors it uses a specially (vendor-optimised) subroutine library (see http://www.mathworks.com/access/helpdesk/help/tech doc/rn/r14sp1_v7_0_1_math.html [mathworks.com] ) For SUN machines, it uses SUN's optimised subroutine library. For other processors (for which there are no optimised libraries) Matlab uses the ATLAS routines. Despite the great progress and portability that the ATLAS library provides, carefully optimised libraries can still beat it (see the Intel Math Kernel Library at http://www.intel.com/cd/software/products/asmo-na/ eng/266858.htm [intel.com] )

Summary

In summary:

-large tracts of Scientific computation depend on optimised subroutine libraries

-hand-crafted assembly-language optimisation can still outperform machine-optimised code.

Therefore the objections that the hand-crafted routines described in the article distort the comparison or are not representative of real-world performance are invalid.

However ... it's so expensive and difficult that you only ever want to do it if you absolutely must. For scientific computation this typically means that you only consider handcrafting "inner loop primitives" such as the BLAS routines, FFT's, SPARSEPACK routines etc. for this treatment, and that you just don't attempt to do that yourself. Typical Scientific users don't write such code (they wouldn't know how, myself included) they buy it from vendors such as Intel and AMD and SUN or specialised software makers like Mathworks (they produce MATLAB). If no such library is available (or affordable), then automatically tuned routines are a very good second-best (and much better than naive self-coded subroutines).

Re:What about the compiler? (1)

Frumious Wombat (845680) | more than 8 years ago | (#15420693)

Actually, for my field (Chemistry), what GCC -O3 does is irrelevant, except during the development phase of a program, or as a last resort for portability. We care about what the fastest native compiler we can find + optimized libraries does. The Cell will be no different; a few hand-optimized routines such as BLAS, FFTPack, etc, in libraries, then an auto-vectorizing Fortran-95 compiler on top. I will be interested in seeing how packages such as GAMESS or NWChem http://www.emsl.pnl.gov/docs/nwchem/nwchem.html/ [pnl.gov] behave once Fortran is available, and Cell shipped in something other than game consoles.

On the other hand, the GROMACS guys http://www.gromacs.org/ [gromacs.org] , who write hand-optimized code on a per-processor basis, ought to be stoked. It already runs well using single-precision, so it looks to be tailor-made to a Cell-based setup.

Re:What about the compiler? (0)

Anonymous Coward | more than 8 years ago | (#15420709)

For crying out loud....

importAnt thAn

Have you learnt the alphabet yet?

Xbox 2 is a "commodity" (-1, Flamebait)

Anonymous Coward | more than 8 years ago | (#15419916)

From the HPCWire link:

"We also conclude that Cell's heterogeneous multi-core implementation is inherently better suited to the HPC environment than homogeneous commodity multi-core processors."

Guess that means Xbox 2's three identical general-purpose processors are inherently lacking in their high performance computing ability. And those are just fight words calling it "commodity".

PS3 will have better AI, better physics, and better games.

Re:Xbox 2 is a "commodity" (0, Offtopic)

Adult film producer (866485) | more than 8 years ago | (#15419931)

Re:Xbox 2 is a "commodity" (1)

PhotoBoy (684898) | more than 8 years ago | (#15420053)

Except neither of those links point to anything that proves the Cell is good for High Performance Computing which is the point of the article. This isn't anything to do with 360 vs PS3. If MS wanted to design a CPU that could be scaled up for HPC they would have done, instead they just got IBM to customise a PPC chip for their games console because their goal is dominance in the living room, not to become the next Intel.

To be honest I question the validity of this study anyway, I seem to recall lots of papers proclaiming the PS2's so-called "Emotion Engine" as the future of super computing and that never happened either. This is probably more hype paid for by Sony to make people believe the PS3 will be the second coming.

Plus if you actually watch that whole interview with Carmack you linked to, he says the only advantage of the PS3 hardware is peak performance, which if it's anything like the PS2 will be limited by memory bandwidth. And everything I've seen of the PS3's RSX suggests it's just an nVidia 7800 GTX, which means the 360 should have the advantage graphically. With the PS3 having more CPU power but the 360 having more polygon power I suspect we'll end up with fairly similar looking games.

Re:Xbox 2 is a "commodity" (0)

Anonymous Coward | more than 8 years ago | (#15420146)

John Carmack is probably the most emasculated, infantile, spineless game developer out there. This is what his whining sounds like to me, "It's too hard! I don't want to work for my money. I just want to program in Python and hopefully interpret something, boo hoo."

It's game developers like Naughty Dog who show the skill and fortitude of innovators. Instead of complacently licensing some hand me down game engine from Epic Games, they opted to hand optimize, custom code, and basically create their own sophisticated and Unix philosophy-adhering game engine.

For example, here's a quote from Naughty Dog game designer Evan Wells in a Q&A with IGN [ign.com] , "Like the PS2 the PS3 is a sophisticated and powerful piece of hardware. Our engineers are working very hard at making specific optimizations to take full advantage of the Cell and its SPU's. However, there is so much depth to this machine, that much like the PS2, you will continue to see developers squeeze more and more out of it over the course of what I am sure is going to be a lengthy life-cycle."

He continues, "The engine we are using is completely proprietary and is being developed here at Naughty Dog. We have some of the industry's top engine programming talent dedicated to getting the most out of the PlayStation 3 possible. With the introduction of the SCE Worldwide Studio there has been an increased sharing effort between the internal teams. It extends far beyond Naughty Dog and Insomniac this time and I think you'll see a lot of first party titles that reap these benefits."

When John Carmack can stop text messaging his Neopets buddies on cellphones while trying to develop a mobile MMOG (WTF?), I may actually think he matters anymore.

Re:Xbox 2 is a "commodity" (0)

Anonymous Coward | more than 8 years ago | (#15420194)

"With the introduction of the SCE Worldwide Studio there has been an increased sharing effort between the internal teams. It extends far beyond Naughty Dog and Insomniac this time and I think you'll see a lot of first party titles that reap these benefits."

Wow. Is the same SCE Worldwide Studios that brought me God of War? Dude, suite. If Naughty Dog and all other first party developers or even Insomniac are going to be reaping benefits from this sharing of manpower, there's no telling how much better Resistance: Fall of Man is going to get and blow gamers away. It could quite possibly shut Gears of War down because that chainsaw is going to get old but 8 to 32 online players in Resistance on the Cell processor is going to exude replayability. And yeah, John Carmack is dead. Doom died when Insomniac entered the FPS market with Resistance. Can't wait.

Re:Xbox 2 is a "commodity" (0, Offtopic)

vertinox (846076) | more than 8 years ago | (#15420171)

Wow, if nothing else the MGS4 demo has left me jaw dropped. That is some friggin high poly count. I was kind of doubtful of the PS3 thinking it would be just a Xbox 360, but that video looked awesome.

(Although, I dunno if it is still worth the price tag though)

Re:Xbox 2 is a "commodity" (2, Informative)

Darkfred (245270) | more than 8 years ago | (#15420482)

Did Sony pay you or did Mr. Kutaragi come over to your house and type it for you.

Have you seriously never seen anything like this before? As a professional ps2/360/ps3 developer I have to say that I was seriously underwhelmed by this demo. Every one of the effects has been used before. THe original xbox has every effect he mentioned. And HL2 has a significantly more complex lighting system and postprocessing effects.
The demo appears to be a single high-poly character in a texture mapped box. The demoer admits that this is a cut-scene quality model. I believe this scene could be rendered on an original xbox with similar 'visual' quality. Why not use some of those polys to make a realistic background? Black on PS2 looked better. And they couldn't even show a solid second of actual gameplay.
I think it will be an amaxing game, but the demo was no technical achievement. It was a hurried render test for an obviously incomplete engine. Bragging about poly count when your competition can push 1.5x-3x as many is not going to win them any points either.

Regards,

Re:Xbox 2 is a "commodity" (0)

Anonymous Coward | more than 8 years ago | (#15420759)

Did Bill Gates pay you to type that up? Or are you just a Microsoft fanboy? You assumed that the MGS4 trailer was pre-rendered cutscene, that obviously shows that you have little knowledge of the PlayStation and MGS. MGS has NEVER used pre-rendered cutscenes. The original Xbox CANNOT produce similar quality as MGS4. Snake's hair alone would cause the original Xbox to be at its limitation.

Finally, where did you hear that the Xbox360 can push 3x more polygons than the PS3? Your ass? You are NOT a developer, and it is obvious from your lack of knowledge in the subject.

Re:Xbox 2 is a "commodity" (0, Flamebait)

Anonymous Coward | more than 8 years ago | (#15419940)

I know you console players just grew your pubes, and this might be hard for you to understand, but Cell will be available in workstations and clusters. XBox's CPU is a one-off for a game console.

Re:Xbox 2 is a "commodity" (2, Insightful)

MooUK (905450) | more than 8 years ago | (#15419988)

I think you misunderstand what HPC actually is.

High performance computing is that which you'd want to throw a huge Beowulf cluster at, or possibly a supercomputer or twenty. Not three small pathetic cores.

Re:Xbox 2 is a "commodity" (1)

Anonymous Coward | more than 8 years ago | (#15420070)

"We also conclude that Cell's heterogeneous multi-core implementation is inherently better suited to the HPC environment than homogeneous commodity multi-core processors."

Whether or not HPC is something you'd want to throw 20 or more supercomputers at in a Beowulf cluster, at least you know that the PS3 is really the only next-generation video game system because nobody concerned with raw performance and power efficiency would want to use the Xbox 2 in a HPC environment.

Re:Xbox 2 is a "commodity" (1)

KitesWorld (901626) | more than 8 years ago | (#15420174)

at least you know that the PS3 is really the only next-generation video game system because nobody concerned with raw performance and power efficiency would want to use the Xbox 2 in a HPC environment.

Not quite. What they're saying is that the Cell is better suited to parralel applications, like physics simulations, and that it is more scaleable - ie, easier to build supercomputers or distributed computing nodes from.

However, that has no bearing upon what 'generation' the host console is - largely because a console has a pre-determined number of chips installed, and cannot be scaled without breaking it's own specification. Remember, the fact that there are exactly n cores in a console is what makes that console a stable development platform (as opposed to the PC, where performance is different on each unit).

You *could* argue that console is using more modular technology, but that on its own doesn't tell you anything about overall performance, ease of development, stability, robustness, nor any of the other metrics that you can really apply to a console. If 'older' technology can be used to provide those same metrics in a home console, then which is better simply becomes an issue of cost. If the older gear does the same job, but is cheaper to produce, then it is the better alternative from everything but a marketing standpoint. Expandibility of the hardware in other platforms does not affect the quality of the platform in question.

Multimedia server (0, Redundant)

podz (887481) | more than 8 years ago | (#15419920)

I can't wait to hook one of these babies up as the brain of my house and run concurrent multimedia streams everywhere. Already dreaming of little wireless touch screen terminals next to the toilet, and a waterproof one in the shower :-)

Doesn't it easily scale up? (1, Interesting)

Poromenos1 (830658) | more than 8 years ago | (#15419995)

Doesn't the Cell's design mean that it can very easily scale up, without requiring any changes in the software? Just add more computing CPUs (SPEs they are called, I think?) and the Cell runs faster without changing your software.

I'm not entirely sure of this, can someone corroborate/disprove?

Re:Doesn't it easily scale up? (1)

owlstead (636356) | more than 8 years ago | (#15420112)

Yes, if there isn't any communication overhead between the processors. If you have 100 seperate threads or processes, without (or almost without) any computation, then the application is perfect for multiple CPU's. If there is a lot of communication needed, then much less so. You cannot write an application for 8 cores with very fast communications and expect it to run on multiple processors without any modifications. That's why many parallel processor designs cost more for the networking part than for the processors itself.

Hmm (1)

Poromenos1 (830658) | more than 8 years ago | (#15420135)

Yes, but the Cell is designed to process data in independent packages which are scheduled and sent to processors by the central unit, it's not a traditional multiprocessor system. Hmm, I guess that from the specs the processors could be communicating via the network instead of just buses as well, which would make what you say correct. I guess we should wait and see.

'designed', nothing (1)

Szplug (8771) | more than 8 years ago | (#15420317)

All MP machines have: communication channels, and processors. If the designers envisioned it being used a certain way and optimized it for that, well, what of it? Maybe that's how the standard game API does things but, it's still processors and communication channels. It's more than likely you can get better performance out of it by adapting your problem for it specifically, minimizing communication and keeping processors busy as much as the problem allows, same as for all other MP systems.

Re:Hmm (1)

owlstead (636356) | more than 8 years ago | (#15420758)

The cell architecture makes it easy to distribute workloads, that's true. But that's just the beginning of solving the parallel puzzle. The trick is to spread the workload in such a way that the communication overhead is minimal. Otherwise, it may be wiser to use a different architecture. My guess is that the cell processor is interesting to grid computing, but needs a serious platform, both hardware and software-wise to be viable for the more serious work. On the other hand, IBM should be big enough to handle this.

Re:Doesn't it easily scale up? (1)

jacksonj04 (800021) | more than 8 years ago | (#15420177)

It should be best suited to things needing concurrent, but not parallel processing. For example you could be running several simulations at once, none of which are interdependent. When one is done, the processor can be handed another instruction without needing to wait for the results from everything else.

The code will be the tricky bit.

Re:Doesn't it easily scale up? (0)

Anonymous Coward | more than 8 years ago | (#15420450)

You can plug Cell's together basically, into dual or quad blade configurations and so forth, but greater communications overhead kicks in as noted in the above posts, as is the same for all multi-node systems. However, if one node today with Cell is a PPE and 8 SPEs, in the future you'll very probably see single chips with 16 SPEs and up.

Future "Mac Pro"? (0)

Anonymous Coward | more than 8 years ago | (#15420010)

Apple has said they considered and rejected the Cell because it's more a game-box processor, rather lacking on the multipurpose needs of a general purpose processor. So they would need to put 4 Cells to match the general needs of a Quad core.

Also they considered that one processor change was enough.

But then Apple caters to the scientific community and ignoring the Cell leaves a hole in the market with no Intel alternative in sight.

I hear the delay with the PS3 is because of problems fabricating such a complex en-masse. It must be one hot sonfabeach too.

So is the "Mac Pro" really delayed because of the Cell?

Not likely to be low cost CPUs (1)

maraist (68387) | more than 8 years ago | (#15420019)

An interesting point is that most consoles sell their hardware at a loss. At least the XBox does. This means that there is no guarantee that IBM is willing to sell their CPUs at the same price that one would believe they cost for the PS3.

Moreoever, the scientific community is very likely to push their cell+ architecture and I'm sure IBM would be more than happy to help... For a massive price.

So, when building an HPC system, you're likely to work around the best architecture (the more expensive cell+), and purchasers of the HPC will then have a cray-like proprietary system at enormous cost.

Not that this is a bad thing, I just don't believe this "low cost" "high volume" statement.

WTF? (4, Insightful)

SmallFurryCreature (593017) | more than 8 years ago | (#15420057)

First off you are talking about consoles being sold at a loss. NOT their components.

IF IBM was the maker of the chip they would most certainly not sell them at a loss. Why should they? Sony might sell the console at a loss to recoup the loss from game sales but IBM has no way to recoup any losses.

Then again IBM is in a parnetship with Sony and Toshiba so the chip is probaly owned by this partnership and Sony will just be making the chips it needs itself.

So any idea that IBM is selling Cells at a loss is insane.

Then the cost of the PS3 is mostly claimed to be in the Blu-ray drive tech. Not going to be off much intrest to a science setup is it? Even if they want to use a blu-ray drive they need just 1 in a 1000 cell rig. Not going to break the bank.

No the cell will be cheap because when you run an order of millions of identical cpu's prices drop rapidly. There might even be a very real market for cheap cells. Regular CPU's always have lesser quality versions. Not a problem for an intel or AMD who just badge them celeron or whatever but you can't do that with a console processor. All cell processors destined for the PS3 must be off similar spec.

So what to do with a cell chip that has one of the cores defective? Throw it away OR rebadge it and sell it for blade servers? That is were celerons come from (defective cache)

We already know that the cell processor is going to be sold for other purposes then the PS3. IBM has a line of blade servers coming up that will use the cell.

No I am afraid that it will be perfectly possible to buy Cells and they will be sold at a profit just like any other cpu. Nothing special about it. they will however benefit greatly from the fact that they already got a large customer lined up. Regular CPU's need to recover their costs as quickly as possible because their success will be uncertain. This is why regular top end cpu's are so fucking expensive. But the Cell allready has an order for millions, meaning the costs can be spread out in advance over all those units.

Re:WTF? (3, Insightful)

Kjella (173770) | more than 8 years ago | (#15420261)

So what to do with a cell chip that has one of the cores defective? Throw it away OR rebadge it and sell it for blade servers?

Use it. Seriously, that's why there's central + 7 of them, not 8. One is actually a spare so that unless it's either flawed in the central logic or two separate cores, the chip is still good. Good way to keep the yields up...

Re:WTF? (1)

epiphani (254981) | more than 8 years ago | (#15420433)

So what to do with a cell chip that has one of the cores defective? Throw it away OR rebadge it and sell it for blade servers? That is were celerons come from (defective cache)

Actually, the cell has 8 SPU's on die. It only utilizes seven, specifically to handle the possibility of defective units. They throw the extra SPU on there to increase yields.

Re:Not likely to be low cost CPUs (1)

Oswald (235719) | more than 8 years ago | (#15420062)

Doesn't sound right. IBM isn't taking a loss on PS3 hardware. If anybody is, it's Sony, and they would be subsidizing the volume that would allow IBM to sell the chip (relatively) cheaply.

Re:Not likely to be low cost CPUs (1)

WindBourne (631190) | more than 8 years ago | (#15420262)

I just don't believe this "low cost" "high volume" statement.If not, then you are about the only one. Simply look at the top500.org to see what low cost,high volume produces. My bet is that IBM is using sony to get to high volume rather quickly. After that point, they will start using this in a number of their own systems. And you can bet that this will form the foundation of a very very fast parallel arch for top500. I also expect to see it upgraded to cell+ quickly.

Lattice QCD people: (1)

ettlz (639203) | more than 8 years ago | (#15420025)

Isn't Cell similar to things like QCDOC (from what my LQCD colleagues tell me, it's based on PowerPC, but are there similarities in the wider architecture, interconnects, etc.)? Have any plans to use it here?

Re:Lattice QCD people: (1)

Watson Ladd (955755) | more than 8 years ago | (#15420183)

A little bit. The big difference is the Cell has SPE's which are like DSP's on the chip which are controlled by a PPC processor. QCDOC is a lot of PPC processors connected similarly. Also, memory is symmetric on QCDOC, while it is asymmetric on the Cell. The similarity is mostly in the kind of bus used. Think about one QCDOC node connected to seven QCDSP nodes and only the QCDOC node having a lot of memory and you will have the right idea. Ars Technica had a good review of the Cell.

Translated (-1, Troll)

sl4shd0rk (755837) | more than 8 years ago | (#15420060)

"evaluated the processor's performance in running several scientific application kernels"

Translation: We compiled 2.4 and 2.6 on it and ran convert on a bunch of TIFF images for a couple days.

"then compared this performance against other processor architectures."

Translation: xp woulnd't activate.

Some mothers do have 'em (0)

Anonymous Coward | more than 8 years ago | (#15420064)

Hmmm Betty. The cat did a whoopsee on me cell processor!

The real problem: Double Precision (0)

Anonymous Coward | more than 8 years ago | (#15420067)

The DP performance of the cell isn't that good. You can get that with FPGAs today, and beat that with other chips. When they can get that DP performance on par with the SP performance, even 1/2 of it would be fine, then it will be meaningful.

Not the real issue (0, Offtopic)

argoff (142580) | more than 8 years ago | (#15420098)

The real issue here has nothing to do with the performance and capabilities of the cell processor. The real issue is, can I make a copy, contract out my own fab, and make it without anyone elses permission. If I can, then it will be successfull, if I can't then it is just another proprietary technology that won't give the end user any real advantage over the long term - and thus no real reason to switch from more commoditized technologies.

No great surprise (0)

Anonymous Coward | more than 8 years ago | (#15420151)

Some architectures are better for some things than other architectures. A prime example would be the DSP. It is optimized for a certain kind of calculation. For those it is better than general purpose architectures by orders of magnitude.

Remember the math coprocessor? Back when I was using a 286 cpu, I bought a math coprocessor for $800 so I could do CAD. Maybe someone could put a cell chip on a daughter board to improve the math ability of a regular desktop computer.

When can we start Folding with it? (1)

BartonOC (977544) | more than 8 years ago | (#15420166)

Sounds like this cpu would end up having great folding performance. I so hope the PS3 ends up being hackable and we get to throw Linux on it ;-)

Re:When can we start Folding with it? (1)

ahodes1 (880242) | more than 8 years ago | (#15420197)

Linux will be pre-installed on the PS3 HDD, no hacking needed: http://www.gamasutra.com/php-bin/news_index.php?st ory=9290 [gamasutra.com]

Re:When can we start Folding with it? (0)

Anonymous Coward | more than 8 years ago | (#15420338)

Well that seals my purchase as soon as possible, then. I just hope it's fairly unrestricted. Is there any more info out there on this?

Re:When can we start Folding with it? (1)

newt0311 (973957) | more than 8 years ago | (#15420628)

what would be really good is if we could find a way to also upgrade the ram. in the console, there is unlikely to be much dedicated RAM and that would kill performance. so if we coul grab the power of the cell and increase RAM in the xbox, that would be good. Personally, I think a better alternative would be to grab one of those blade servers and turn it into a slave computer.

The ball is in the hands of developpers. (3, Insightful)

stengah (853601) | more than 8 years ago | (#15420200)

The fact is that most scientists use high-level software (MATLAB, Femlab, ...) to do their simulations. Altough theses scientists may be interested by any potential speed-up to their workflow, they are not willing to invest any bit of their time to translate all their codebase to asm-optimized C. Thus, the ball is in the hands of software developpers, not scientists.

Re:The ball is in the hands of developpers. (3, Informative)

infolib (618234) | more than 8 years ago | (#15420465)

The fact is that most scientists use high-level software (MATLAB, Femlab, ...) to do their simulations.

Indeed, most scientists. They also know very little about profiling but since the simulation is used only maybe a hundred times that hardly matters.

The cases we're talking about here are where thousands of processors grind the same program (or evolved versions of it) for years as the terabytes of data roll in. Such is the situation in weather modelling, high energy physics and several other disciplines. That's not a "program" in the usual sense, but rather a "research program" occupying a whole department including everyone from "domain-knowledge" scientists down to some very long haired programmers who will not shy away from a bit of ASM. If you're a developer good at optimization and parallellism there might just be a job for you.

Re:The ball is in the hands of developpers. (1)

Surt (22457) | more than 8 years ago | (#15420543)

In the article they mentioned that they had ported several scientific kernels to cell, so presumably the porting work isn't going to be the core of the challenge. It sounds like the real work to be done will be convincing sony to make modifications to the next generation of cell processors to improve the double precision performance.

Re:The ball is in the hands of developpers. (1)

fitten (521191) | more than 8 years ago | (#15420768)

The fact is that most scientists use high-level software (MATLAB, Femlab, ...) to do their simulations. Altough theses scientists may be interested by any potential speed-up to their workflow, they are not willing to invest any bit of their time to translate all their codebase to asm-optimized C. Thus, the ball is in the hands of software developpers, not scientists.

Isn't this the same argument as the Itanium proponents used? ...It's up to the compiler writers to make good compilers so the code runs well...

Femlab? (1)

colinrichardday (768814) | more than 8 years ago | (#15420828)

Did you mean Fermilab, or am I not keeping up with scientific progress? :-)

Ease of Programming? (2, Interesting)

MOBE2001 (263700) | more than 8 years ago | (#15420235)

FTA: While their current analysis uses hand-optimized code on a set of small scientific kernels, the results are striking. On average, Cell is eight times faster and at least eight times more power efficient than current Opteron and Itanium processors,

The Cell processor may be faster but how easy is it to implement an optimizing development system that eliminates the need to hand-optimized the code? Is not programming productivity just as important as performance? I suspect that the Cell's design is not as elegant (from a programmer's POV) as it could have been, only because it was not designed with an elegant software model in mind. I don't think it is a good idea to design a software model around a CPU. It is much wiser to design the CPU around an established model. In this vein, I don't see the cell as a truly revolutionary processor because, like every other processor in existence, it is optimized for the algorithmic software model. A truly innovative design would have embraced a non-algorithmic, reactive, synchronous model, thereby killing two birds with one stone: solving the current software reliability crisis while leaving other processors in dust in terms of performance. One man's opinion.

Re:Ease of Programming? (1)

adam31 (817930) | more than 8 years ago | (#15420851)

I suspect that the Cell's design is not as elegant (from a programmer's POV) as it could have been, only because it was not designed with an elegant software model in mind.

It's possible that this is the case, however IBM is actively working on compiler technology [ibm.com] to abstract the complexity of an unshared memory architecture from developers whose goal isn't to squeeze the processor:

When compiling SPE code, the compiler identifies data references in system memory that have not been optimized by using explicit DMA transfers and inserts code to invoke the software-cache mechanism before each such reference.

So for developers who want performance, the architecture is ideal. 2 Megs of L1-speed memory, a 25 GB/s bus servicing 8 processors each with 128 128-bit registers. And for the rest, it's still a high-performance programmer-friendly development environment.

Your point is not going unnoticed by IBM.

And why Apple going Intel was so sad (1, Insightful)

Anonymous Coward | more than 8 years ago | (#15420330)

x86, the commodity, has registers from the days when RAM was faster than the CPU (ie 8-bit days)

The tacked on FPU, MMX, SSE SIMD stuff whilst welcome still leaves few registers for program use

The PowerPC on the otherhand has a nice collection of regs, and as good if not better SIMD--The CELL goes a big step further

More regs = more varibles in the CPU = higher bandwidth of calculation
be they regular regs or SIMD regs.
  That plus the way it handles cache
Could be a pig to program without the right kind of compiler optimizing
Would that mean game developers using FORTRAN 95?

bang, buck, effort (3, Informative)

penguin-collective (932038) | more than 8 years ago | (#15420361)

Over the last several decades, there have been lots of parallel architectures, many significantly more innovative and powerful than Cell. If Cell succeeds, it's not because of any innovation, but because it contains fairly little innovation and therefore doesn't require people to change their code too much.

One thing that Cell has that previous processors didn't is that the PS3 tie-in and IBM's backing may convince people that it's going to be around for a while; most previous efforts suffered from the problem that nobody wanted to invest time in adapting their code to an architecture that was not going to be around in a few years anyway.

Re:bang, buck, effort (0)

Anonymous Coward | more than 8 years ago | (#15420639)

your point about other parallel architectures is only partially valid.

the key to the PS3's possible wealth of utility in scientific computation
won't be due to its architecture but its price, or more accurately, its price/performance.
Just think how much cheaper this unit will be from the effect of however many
million gamers buying it compared to the cost of a high end desktop.
 

single threaded vs multithreaded (1)

abigsmurf (919188) | more than 8 years ago | (#15420421)

I thought the Cells performance was mediocre if you only had a single task going on at a time. Given that scientific simulations aren't real time, it doesn't need to be hugely multithreaded as it's better for each tick/frame/etc of the simulation to be done one after the other.

Re:single threaded vs multithreaded (1)

be-fan (61476) | more than 8 years ago | (#15420716)

1) Cell's performance is mediocre on typical single-threaded applications (eg: AI). Not because it has inherently bad single-threaded performance, but because most single-threaded code happens to be integer code, and the SPE's integer and branching performance sucks.

2) Most simulations are highly parallel. There are lots of cases where you can simulate many parts of the system simultaniously, and only synchronize state at certain points.

Ran simulations, not code (5, Insightful)

jmichaelg (148257) | more than 8 years ago | (#15420570)

Lest anyone think they actually ran "several scientific application kernels" on the Cell/AMD/Intel chips, what they actually did was run simulations of several different tasks such as FFT and matrix multiplication. Since they didn't actually run the code, they had to guess as to some parameters like DMA overhead. They also came up with a couple of hypothetical Cell processors that dispatched double precision instructions differently than how the Cell actually does it and present those results as well. They also said that IBM ran some prototype hardware that came within 2% of their simulation results, though they didn't say which hypothetical Cell the prototype hardware was implementing.

By the end of the article, I was looking for their idea of a hypothetical best-case pony.

14 times slower vs 8 times faster (1)

Kell_pt (789485) | more than 8 years ago | (#15420622)

On average, Cell is eight times faster and at least eight times more power efficient than current Opteron and Itanium processors, despite the fact that Cell's peak double precision performance is fourteen times slower than its peak single precision performance.

So, that means that the cell in it's current design is 14/8= 1.75x times slower for double precision than an Opteron/Itanium is for single precision. I searched around byt couldn't find a good answer on what is the ratio between an Opteron/Itanium single and double power precision performances? If it's actually just 50% slower (as I think it is) then the cell is still slower (currently 75%).

So, anyone knows for sure what is the ratio between an Opteron/Itanium single and double power precision performances?

Re:14 times slower vs 8 times faster (1)

be-fan (61476) | more than 8 years ago | (#15420678)

The Opteron/Itanium's SP/DV performance is about the same.

And you misread the statement. It said that Cell was 8 times faster than Opteron in DP.

Benchmark (1)

roadrouter (953107) | more than 8 years ago | (#15420677)

I don't understand how they can compare the new Cell with a amd64 or an Itanuim and be so happy.

Cell have 8 vector processor and something like a ppc to "control" all of them, it's done specially for FP operations. It's like a comparation of a GPU with a CPU, it haven't got so much sense.

marketing (1)

prurientknave (820507) | more than 8 years ago | (#15420735)

Check if this was sponsored by the same marketing team that was running ads that kept peddling the lackluster g4 as a supercomputer on the national watchlist.
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