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AMD Quad Cores, Oh My
Lullabye_Muse writes "From engadget we learn that AMD has plans for putting 4 cores on one die by the time Apple has fully gone to Intel processors. Full story here. They say they could eventually have up to 32 cores with scalable technology, but most programs haven't even got the ability to hyperthread, so do we really need the extra cores?"
Yes, the poster should have used 'multithread' instead of the Intel branded and copyrighted term, 'HyperThread' which is in regards to their proprietary virtual processor technology on Pentium 4's and Xeons.
Let's not let Intel get the next 'Kleenex'ing of the English language, shall we?
It's more an issue of programs taking advantage of multiple cores or multiple processors than the compiler. Using multiple cores means that a single program must either have multiple concurrent processes or multiple threads, you can't just magically compile that sort of thing in, IPC can be a complex beast. That, or you need to run multiple programs at the same time to take advantage of more than one core at a time.
Game! - Where the stick is mightier than the sword!
Microsoft has said several times that one CPU package == one CPU for the purposes of licencing. They said this for hyperthreading and dual core, both still count as only one CPU. Windows XP will show four CPUs on a dual Xeon system if hyperthreading is on, and it will run.
The word "Hyperthreading" describes a specific hardware kludge by Intel to make a single-core CPU pretend it's dual-cored. Apps that utilize multiple CPUUs are called multithreaded. All you dorks parroting the article submitter and calling it "hyperthreading" are idiots.
If a job's not worth doing, it's not worth doing right.
Yes, Virginia, we can use mutli-core. I mean, we're all into SMP heavily in the non-desktop role (does anyone actually make a "server" that doesn't have SMP?)
There are two big things I love about the multi-core Opterons: They draw less power than equivalent SMP machines (acutally, quite a bit less), and they allow multiple "CPUs" to use the same memory controller. Nominally, the second isn't a big win, but it can be for practical purposes.
Opterons have dedicated memory channels on them, so a current dual-socket Opteron has two DISTINCT DIMM banks - that is, on a motherboard with 8 DIMM sockets, 4 are allocated to each CPU socket. So if you have only one CPU, you can only use 4 DIMM sockets. Since those 4 sockets are often configured as a single bank (i.e. they all have to be filled to work), you can't add another CPU to the system without buying more RAM. This is wasteful. But with a multi-core opteron, all on-chip cores share the same memory bank.
The jist of this is that it'll be easier to have High-Compute, lower RAM configurations than it currently is reasonable to do. There are a lot of tasks out there which it is really nice to have a modest amount of RAM (say 4GB), but with huge crunch. Currently, it's hard to buy a config to do that, since you generally either end up way over-paying for CPUs, a huge number of tiny DIMM chips (which sucks for future expansion), or a larger number of motherboards, which draws more power.
And, hey, they're not tooo bad in price. Sun's dual-core v40z is less than twice as expensive as their single-core v40z, and you save lots on power/cooling/space.
Overall, a nice win.
-Erik
There are always four sides to every story: your side, their side, the truth, and what really happened.
He shows demos and explains several driving forces:
An example of video analysis is demonstrated. You can get a stable image out of a cell phone, and get a much higher resolution to boot, simply by analyzing lots of images in sequence. Right now, it takes a lot of time to crank out the analysis. But the problem is parallelizable, and Intel thinks we'll have this sort of things in cell phones by 2015.
This is also the technology behind automatic construction of 3D from images. This is where you pull your cell phone out, walk around, waving it around the room, and get back a 3D model of the room.
People ask: "Do we really need all this computing power?" Yes, yes we do. There's plenty of stuff to do with it.
Scott talks about sitting in front of the computer, and not needing to log in, because the computer knows who you are by your face.
There's all kinds of stuff to do with it.
You dont understand:
HYPERTHREADING =! MULTICORE.
These are 2 complete cpus+a crossbar switch on one die. No shareing of execution units/registers,no sharing of anything but the ram bandwith.
Amd dual core cpus are FASTER than 2 single core cpus in dual socket boards (with the exception of extremely bandwith demanding streaming applications) simply because of much faster on-die cache coherence communication.
A quad core cpu will most likely see more bandwith problems, but could (with ddr-2, ect) still be very well in the same class as a 4 single-core machine.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
SMP or multiple cores is (obviously) more than one real processor and one will see huge benefits with any application that is multithreaded as well as when running multiple processes. Single threaded processes should never have issues running on an SMP system, though there will be a small loss of speed due to the overhead of SMP (Dual 2 Ghz processors will probably run a single threaded process ~1% slower than a single 2 Ghz processor).
Game! - Where the stick is mightier than the sword!
I thought SOI was IBM's patent which it shared with AMD-- if so, its not AMD's to license.
Synergies are basically awesome, and they're even better when you leverage them. -PA
The Cell's SPEs aren't really general purpose. They're limited to a 256KB local storage. In order to utilize main memory, they have to use explicit DMA operations. That drastically limits their usefulness for code that isn't explicitly written for Cell.
A deep unwavering belief is a sure sign you're missing something...