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Are three cores better than two?
Barbarian writes "That's the question that Tom's Hardware asked. They took a dual-cpu motherboard and stuck both a single and a dual core Opteron on the board, for a total of three cores. Does it work? Well, yes, when it's not crashing. It does raise the possibility of tri-core processors whilst we are waiting for the next die shrink."
If only you would lift the power supply 3 feet above the ground,.. Oh wait..
Today on /. 3 > 2!!! Tommorow 4 > 3!!
I thought the XBox CPU was a three-core jobby. I don't know if all the three cores are the same or whether thre are different sorts of cores for doing different sorts of things. Presumably, as long as you've got the correct glue, and can stick any number of cores on a chip. I don't think there's any need to stick (sorry!) to powers of two. Whether or not it works better efficiently becomes the issue... or rather the ability to market three vs two or four becomes the issue!
return 0; }
Why not try 4?
"Xbox 360 is a triple core, which is a pretty good indicator that this configuration is viable"
Wasn't XBox crashing constantly?
[sig]
The question can't be answered.
In some markets, hardware is released and only then does software take advantage of it. Sometimes software never takes advantage of the new hardware because of the complexity in writing code. I remember all the MMX and the like promotions, but I never really saw any evidence that it did anything.
In other markets, software is released and the hardware follows. I recall Quake (or was it Quake 2) and the rush months later to have a Voodoo SLI to boost framerates.
I am sure a 3-core processor could be "better" but only if the software to support it can be easily ported from the single core or dual core versions. Will software eventually be core-transparent because of a "xCore" abstraction layer? Will software be optimized properly for the ability to take advantage of the added cores?
I see the need for multitasking the processor side, but I also see the complexity in trying to differentiate all the different configurations a workstation may have. The more cores that are released, the more I see application-specific turn key solutions over "one version fits all." I also see the added costs in testing and developing, and who really knows if those costs lead to any savings by creating the additional cores.
That's the point of this post -- just because something increases efficiency in one sphere doesn't mean that there is an overall savings. There is no way to properly judge if the market will see a savings overall, and if it costs much more to produce/support/service the new product, it will fail. Nothing can stop that, not even great marketing.
I'm sure using anything other than a power of two irritates the binary gods, at least use an even number.
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Pages are loading pretty slow, here's the conclusion for those who don't want to wait:
As you could see, the fact that we used two rather different Opterons for putting together the triple core system had an impact on the benchmark results that was hard to predict. Performance depends on the level of a program's thread-optimization, but we also had a hard time with some particular benchmarks. Some did not work at all (AutoGK w/ DivX or Xvid, Pinnacle Studio 9 Plus). For others, performance was worse than that offered by a dual-core Opteron 275 configuration (such as with memory benchmarks, ScienceMark, WinRAR file compression and Windows Media Encoder). However, the majority of software we used was able to scale well thanks to the third core (which was the case with Cinebench 2003, PovRay 3.7, Cinema 4D R9 and 3DS Max 7).
MrRogers(2)
isnt even ready for multithreading yet.
Gaming is where the horsepower is needed in the consumer space - and most games aren't multithreaded. An additional core wont do much in terms of performance that a second core doesn't already accomplish. You're just wasting die space and decreasing yields.
The Doormat
If you're not outraged, then you're not paying attention.
Why would anyone even want to do this? Most dual proc systems are designed so that the CPUs must be the same for them to work properly. Sure, this configuration is a bit cheaper than using two dual core procs, but unless you have a space CPU sitting around I really don't see the point.
As a senior Death Star Engineer, I don't think this is such a good idea at all. Despire the Governor's claims that the rebellion poses no threat, having not one, but three massive vulnerabilities on our defenses is only asking for a "small, one-man fighter" to score a direct hit.
Hehe, reminds me of The Onions article about five razor blades vs four.. Interesting that they wrotes this WELL before a 5-blade razor ever came out
First of all, they used Windows XP SP2. Why the fuck would you do that in a multicore test. Use an OS that can handle that many cores properly. XP definatly can't. Not bashing windows either. I mean if you are going to use a windows OS at least use 2003 server. And why just test one OS? Also, the triple core title is completely misleading. The AMD arch for multicore processors is much more than just two cores stuck in a single incasing (ala Intel's design). It's much more advanced and just sticking a 2nd cpu into a multicore setup is not analagous to adding another core to the tight multicore setup. It's adding a whole 'nother cpu.
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The article refers to the system as "asymmetric" in a few places. This is not the case: SMP refers to a situation where all CPUs run a kernel, and each CPU schedules jobs for itself. In an AMP situation, one CPU is the "master" and the others are "slaves" which are scheduled, have interrupts and system calls managed by, and are otherwise controlled by the "master" CPU. It's possible to have an SMP tri-core system, and an AMP dual-core system.
Well, yes, the crashing is a problem, so lets just agree that 3 Coors are better than two unless you're driving.
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That sounds more like game programmers are wasting their time making games that don't make use of multiple CPUs. It's very clear that there are starting to be some limits reached in terms of what one CPU can do in a machine. There's a reason all these manufacturers are making dual core processors instead of making their processor faster. It's time for the programmers to change how they program.
So, I think your comment isn't very useful, since you try to tell hardware manufacturer's that they're doing useless things instead of making the single CPU faster. And that's not true at all. It's the game programmers that are doing stupid things. Going from 1 to 2 is would've been hard to deal with before it happened. But once you have, going from 2 to x is much easier. So, testing out three and more core systems is pretty useful.
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These two processors do not only differ in the manufacturing process: Changes to the memory controller have been made during the transition from 130 to 90 nm and SSE3 extensions were added. Opteron 248 was designed for HT800 (200 MHz bus), while the Opteron 275 is capable of running HT1000. Finally, the cache size per core is different as well.
My guess is the crashing programs are detecting SSE3 and when a thread that uses it runs in the single core processor, the application is killed for trying an "illegal instruction."
We have tested a car with three tires instead of four. Does it work? Well, yes, when it's not crashing.
This is got to be one of the most pointless experiments ever done. Does it work? Yes it works when it's design to work, like the XBox 360. SMP stands for SYMETRICAL MULTIPROCESSOR. A dual core and a single core are not symetrical
please excuse my apathy
Why not setup one core heavily interger optimized, and one floating point? That way you can run the FP apps like rockets, and the interger apps like lightning w/o comprimizing on either. Rather than have a long chain in the pipeline you could have paralell paths, and once an instruction is set down one path, the CPU could take the next and see if it can stick it down another path.
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...on Tom's multi-page reviews.
I hate sites where the article occupies less than 10% of the screen area.
I think they had problems scaling their budget.
You mean to say that the TEST COMPUTER was not meant to be set up this way. Just as it's only by convention that computers use binary (they could use any imaginable base representation), it's only by convention that easily-obtainable computers use processors in groups that are integer powers of two. There's no physical reason why a computer could not be built that used an odd number of processors very well, it's just that the one used for the test was not meant for it.
Look what failed. Video compression programs, the type of code almost certain to use streaming SIMD operations.
Try this with two identical dual processors and you should get a nice 4-CPU machine.
Opteron systems aren't SMP. They're NUMA.
In theory, the ability to run to chips of different speeds was there even in the Athlon MP, as it had independant busses from the morthbridge. In practice, it didn't work very well, either.
steve
Oh, you're not stuck, you're just unable to let go of the onion rings.
Apparently it's the mammoth power brick which causes most of the problems, coupled with people putting it in areas without good circulation (not necessarily the consumers fault... most entertainment centers are kinda cramped). Microsoft is saying that the defect rate is 3%, I'd believe something closer to 6%, but that is actually not out of the ordinary for consumer electronics.
So, in my mind, the "viability" issues of three cores has been answered with the 360. And in fact there are Power Mac configurations that effectively give you 4 cores (2x dual-cores). However, the bigger question is whether it will be advantageous .
With that in mind the 360 is a pretty good test-bed to see 3-core configs are worthwhile. Developers will have more incentive to exploit the potential with the assurance that the hardware will remain relatively constant (at least as far as the API is concerned... hopefully Microsoft will be able to come out with a more compact 360 in a few years).
It's not that rewarding because the memory bandwidth and low-latency local memory must increase as well to be able to feed the computations. In fact, I will guess that even at a massive 25.6 GB/s bandwidth on the PS3, a properly architected game will still be bus-bound.
So, in the short term parallelization will take the form of tasks that are compute-heavy and don't need to be sync'ed. Cool particles, or cloth sims, or asset streaming and decompression. Then it's a diminishing returns game as we move from 4 procs to n.
I know replies have probably already covered this, but here it is one more time. The Xbox 360 uses 3 PowerPC cores (kind of funny for Microsoft to use PowerPC CPUs isn't it?). The new Xbox has major problems with heat, which can also be attributed to the power supply adding to the mess. A previous story said that at least one person was hanging his power supply by a string to help out, which is ridiculous.
We have hit a brick wall so to speak at which processors have been limited. There needs to be major changes in the way that the dies are manufactured before we can attain much higher speeds while keeping stability. One option is to stop using silicon to produce the circuitry, however thus far there are no economical solutions.
If you really need the extra processor power, network a couple of computers together and configure them to share their resources. This takes up more space, but is the only realistic answer that I can think of right now.
It may be 1% today.
It will most likely be 25% in 12 months. Well, 90% if you count PS3 and Xbox 360.
Trust me, current games under development for release mid-2006 or later are looking at this (as are everyone developing anything for future consoles). They have to - competition will pwn their ass with much shinyer games that take advantage of the extra hardware, and their product will look dated if they don't do the same thing.
Due to long development times, most of the games out now do not benefit, but that will change - rapidly. We've already seen first ones that clearly benefit (City of Villains uses and benefits noticeably, assuming your videcard is modern enough so it's not limited by it).
I'd get the same effect if I tried driving my car on the freeway with three wheels.
Just a pointless observation. I'm good at those.
Just as it's only by convention that computers use binary (they could use any imaginable base representation)
Not so fast there. If you tried to build a base-3 computer you'd have some much more difficult problems on your hands in terms of the actual hardware, which would have to deal with three possible levels instead of two. Needless to say, that would complicate things tremendously and probably lead to more error as devices had to deal with three input/output signal ranges. Yeah, it's a convention that computers use binary but it's a convention with a good reason (a stronger reason, certainly, than that of the arabic base-10 number system, though that's not a bad reason at all).
If you're talking about software's use of binary, I think that makes a lot of sense too. The only time you really commonly see binary or hexidecimal these days is when you're working with memory addresses. In a 32-bit address space, it's nice to know that any number that fits in 8 hex digits is within the range of addresses (which is much easier than remembering some number that's approximately 4 billion but a little more), and using binary or hex makes bitwise operations like masking much easier (i.e. 0x00FF AND 0x1189 is 0x0089; in decimal that's 255 AND 4489 is 137). The reason it's easier is that each hex digit always represents exactly 4 binary digits, while a given decimal digit's value can depend on every binary digit in the number. So as long as we're on binary hardware, we're going to have lots of use for binary and hex in software.
As far as number of processors go... there's really no reason that three processors wouldn't work. Things like processors are typically added in powers of two, however... one reason is probably that it takes 2 bits to address 3 processors, and also 2 bits to address 4 processors. That is, that it often takes a much bigger architectural change to cross a power-of-two boundary (2 to 3, or 8 to 9) than to fill up to a power of two (3 to 4, or 9 to 16).
And as for the computer being tested, many dual-CPU setups like to have the exact same processor in both slots. I would go so far as to say that the vast majority of dual-CPU systems are this way, whether the motherboard likes it or not. This system uses two CPUs with 3 total cores; to the board and to the software this looks like two different types of CPUs, a setup that it might not handle so well. In this sense, it is that this particular test computer doesn't deal with the asymmetry well.
Obviously not. From TFA's first page:
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I've been using a Sun E450 with 3 processors for the better part of 5-6 years. Not sure how well it "balances" the load, but when I use TOP it seems to indicate that Solaris is in fact spreading the load appropriately.
This may be my lack of knowledge about computer engineering (despite my CS degree ;)), but how would we use any representation other than binary? Do we have transistor logic that can do base three, or any other base? Isn't it all based on logic gates, which are inherently binary?
While there are numerous very good reasons for computers to use binary, it is not impossible to build a computer that use, say, base three or any other low base for that matter. On the transistor level there is no such thing as 1 and 0, only voltages, and while an engineer designing a logic circuit will usually define a few volts to mean 1 and no voltage to mean 0, it is quite possible to define 2 * a few volts to be 2 and go ahead and design a base three circuit - take a look at this for more info on base three computing (google's cache of it since the site appears to be down).
I still believe that there are good reasons that contemporary computers use base two - a lot of things become simpler when you don't have to worry about multiple voltage levels, only wether it's "a few volts" or "about zero volts."
And once you've finished reading up on base three computers, there's always more interesting stuff to read on the net.
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I'm guessing there could be a lot done with AI that wouldn't require heavy communication between the different AI components. So, with careful design, most of the AI could fit in L1 cache andd be executed by one core without any bandwidth constraints.
Automota based models for physics engines might also be able to make good use of large numbers of parallel processors. I bet there are some interesting techniques for this in the scientific supercomuting sector that I don't know about yet.
Need a Python, C++, Unix, Linux develop
Have you ever spent time in mainframe environments? There are all kinds of "wacky" architectures to be found there.
My first job out of college was on a susyem with 3 CPU's. It was an MAI/B4 MPx8000 series mini. It had 9MB of RAM. Weirdly, the OS word size was 24 bits. Blocksize on the disk was 768 words.
I am very small, utmostly microscopic.
Your honor, this may *seem* offtopic at first, but I do have a point to make.
I think that the Open Source community has proven that anything will work given enough engineering hours. Case and point; I was at Phreaknic many moons ago and saw a TRS-80 running Debian. Yay!... but now what? Would you use your Debian-laced TRS-80 to do someting? (not knockin' it.. it was actually pretty cool, but it's a pertinent example towards my point)
Just as Debian was able to be loaded on the TRS-80, a tri-core setup will, in all likelyhood, benchmark better than a dual setup assuming that the tri-core configuration can be stabilized (which I don't doubt is possible) and the application(s) are optimized for multiple processors. Ok, by proving that, what have we accomplished? 3 are better than 2? Of course 3 are better than 2. I personally think that a *good* question to ask would be: Are there advantages to using 3 versus 4? Or what advantages could you leverage from a 2 + 1 configuration?
Bottom line: Did you really have to do an experiment to test that?
Seems like one of those "chickens prefer beautiful humans" research projects. Google it; the research project is there.
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Most computers these days have an odd number of CPUs...
Please note that "TriCore" is a brand name (of Infineon, formerly Siemens Microelectronics).
It is an instruction set architecture (and a set of CPU cores that implement it). It is "Tri" core because it:
1) is a RISC architecture (for high crunch in low footprint) which
2) has instructions and data paths to do DSP work efficiently and
3) has the interrupt / task switching mechanisms to do real-time controller work efficiently, as well.
this gives ASIC designers a core that handles all three major sorts of embedded processing well in one package.
I suggest we stick to "triple core" (as most of the posters so far have) to avoid confusion between a chip with three cores and this branded single core that does three jobs well.
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These are basically the oddest benchmarks I've seen in a while, and nobody even seems to notice. Take for instance the "Cinema 4D R9" test; single Opteron, dual Opteron and dual-core Opteron are basically tied (the singe single-core is even a tiny bit faster!), but dual-core+single-core Opteron is a lot faster... Shouldn't such oddities (and that's not an isolated case) be at least commented on and explained in some sort of way if you want people to buy into your statistics at all? And why didn't they benchmark the rather obvious configuration of two dual-core CPUs?
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Sun has released its T1 chip which boasts 8 cores capable of running 4 threads each. As mentioned on slashdot before, its considered a "green" chip becuase it only requires aprox. 70 watts to run (think lightbulb). Sun has a 2U server with this chip, 32 Gigs of ram and 2 SAS drives all for around (or under) $30k. This is complete redesigning my future datacenter planning. Oh yeah. I forgot to mention, This is shipping now and runs only Solaris 10.