Intel's Dual-core strategy, 75% by end 2006

DigitumDei writes "Intel is moving ahead rapidly with their dual core chips, anticipating 75% of their chip sales to be dual core chips by the end of 2006. With AMD also starting to push their dual core solutions, how long until applications make full use of this. Some applications already make good use of multiple cpu's and of course multiple applications running at the same time instantly benifit. Yet the most cpu intensive applications for the average home machine, games, still mostly do not take advantage of this. When game manufacturers start to release games designed to take advantage of this, are we going to see a huge increase in game complexity/detail or is this benifit going to be less than Intel and AMD would have you believe?"

Comments

So Intel's going to be a year late ?.

[Gopal.V]

AMD demo'd their dual core x86 a year ago. Also from what I read, the Pentium extreme is NOT going to share the memory controller - which means unlike the AMD, we might need a new motherboard for the dual core ones (well, AMD promised that we wouldn't). So this is costlier, uglier and more power hungry.

All in all I see that Intel is going down unless they do something quick. And remember Competition is good for the Customer.

Meanwhile back in PPC land

[Anonymous Coward]

I find this interesting, every machine Apple sells except at the definite low end is dual CPU SMP now, and it's been this way for awhile. Now Intel/AMD seem to be realizing "oh yeah, dual cpus, maybe that's something we should start targeting for the mass market instead of just the high end" (though AMD seems to be pretty comfy with the idea already). I wonder why Apple doesn't seem interested in dual cores though. Intel/AMD seem to be treating multicore tech as their way of getting SMP out of the power-user range, Apple doesn't seem to want to have anything to do with it even though POWER has had multicore ability for a really long time. What's up with this, is there something I'm missing?

Make sure you first don't pay double

[bigtallmofo]

Check your licensing agreements before you buy one of these dual-core processors. Make sure that your software vendor isn't going to double the price on you.

Oracle and others have announced plans to increase their revenue by charging people for multiple cores in their single processor.

Games and multi core

[Anonymous Coward]

As already mentioned games already do make use of the GPU and the CPU so we're fairly used to some mutliprocessor concerns.

To say that most PC games are GPU bound however is a mistake - most games I've come across (and worked on as a games core technology/graphics programmer) are CPU bound - often in the rendering pipeline trying to feed that GPU.

Anyhow games are already becoming dual-core aware. Most if not all multiplayer games make use of threads for there network code - go dual core (or hyperthreading) and you get a performance win. Again most sound systems are multi threaded often with a streaming/decompression thread, again a win on multi core. These days streaming of all manner of data is becoming more important (our game worlds are getting huge) and so again we will be (are) making use of dual core there too.

I personally have spent a fair amount of time performance enhancing our last couple of games (mostly for HT but the same applies to true dual core) to make sure we get the best win we can. For example on dual core machines our games do procedural texture effects on the second core that you just don't get on a single core machine and still get a 20% odd win over single core. I'm sure most software houses take this as seriously as us and do the same. It's very prudent for us to do so - the writings been on the wall about multi processors being the future of top end performance for a while now.

At the end of the day though us games developers have little choice but to embrace multi core architectures and get the best performance we can. We always build software that pushes the hardware to the full extent of it's known limits because that's the nature of the competition.

Just think what the next generation of consoles is going to do for the games programmers general knowledge of concurrent programming techniques. If we're not using all of the cores on our next gen XBox or PS3 then our competition will be and our games will suck in comparison.

Do they share the cache?

[jbb999]

Do these new chips share the highest speed cache? I can think for several ways to make use of them without using traditional threads. For example: Set up a pool of threads each one of which just reads a function address from a queue of work and then calls that function, waiting when there is no work. The main program can then just push function pointers onto the queue knowing that a thread will pick up the work.

I'm thinking that instead of writing something like
for(int i = 0; i < NumberOfModels; i++) {
UpdateModelAnimation(i);
}

you could write

ThreadPool* pool = new ThreadPool();
for(int i = 0 ; i < NumberOfModels; i++) {
pool->QueueAsyncCall(UpdateModelAnimation, i);
}
pool->WaitForAllToFinish();

The queueing of work could be made pertty low overhead and so if there were only a few thousand CPU instructions in the call you'd get a big speed up, but only if each processor already had the data they were working on in cache. If each core has a separate cache this would be a lot less efficient. Does anyone know?

Re:Memory latency is the limiting factor

[MindStalker]

Not nessesarly, as both cores share the same memory controller and registered memory, latency from core to core is essentially zero. I wonder if someone could write some really smart code that has one core doing all memory prefetching and the second core doing the actual computations. Could be interesting.

One possible multi-threaded benefit

[JSBiff]

I would like to see a more multi-threaded approach to game programming in general, and not all the benefits would necessarily be about performance.

One thing that has bugged me a long time about a lot of games (this has particular relevence to multi-player games, but also single player games to some extent) is the 'game loading' screen. Or rather, the fact that during the 'loading' screen I lose all control of, and ability to interact, with the program.

It has always seemed to me, that it should be possible, with a sufficiently clever multi-threaded approach, to create a game engine where I could, for example, keep chatting with other players while the level/zone/map that I'm transitioning to is being loaded.

Or maybe I really want to just abort the level load and quit the game, because something important in Real Life has just started occuring and I want to just kill the game and move on. With most games, you have to wait until it is done loading before you can then quit out of the game.

In other words, even ignoring performance benefits for a moment, if a game engine is correctly multi-threaded, I could continue to have 'command and control', and chat, functionality while the game engine, in another thread, is loading models and textures.

Re:One possible multi-threaded benefit

[nounderscores]

In other words, even ignoring performance benefits for a moment, if a game engine is correctly multi-threaded, I could continue to have 'command and control', and chat, functionality while the game engine, in another thread, is loading models and textures.

That would put the pressure back where it should be - on the level designers - to make sure that each segment was challenging enough so that a player couldn't pass through two loadzones simply by running so fast that the first zone hasn't fully loaded yet and wind up in a scary blank world full of placeholder objects.

Performance plateau and functional programming

[barrkel]

I believe that we're going to see a performance plateau with processors and raw CPU power for the next 5 years or so.

The only way CPU manufacturers are going to get more *OPS in the future is with many cores, and that's going to require either slower or the same kind of speeds (GHz-wise) as things are today. To get programs to run faster under these circumstances you need some kind of explicitly parallel programming.

We haven't seen the right level of parallelism yet, IMHO. Unix started out with process-level parallelism, but it looks like thread-level paralellism has beaten it, even though it is much more prone to programmer errors.

On the other end of the scale, EPIC architectures like Itanium haven't been able to outcompete older architectures like x86 because the explicitly parallel can be made implicit with clever run-time analysis of code. Intel (and, of course, AMD) are their own worst enemy on the Itanium front. All the CPU h/w prediction etc. removes the benefit of the clever compiler needed for EPIC.

Maybe some kind of middle ground can be reached between the two. Itanium instructions work in triples, and you can effectively view the instruction set as programming three processors working in parallel but with the same register set. This is close (but not quite the same) to what's going to be required to efficiently program multi-core CPUs, beyond simple SMP-style thread-level parallelism. Maybe we need some kind of language which has its concurrency built in (something sort of akin to Concurrent Pascal, but much more up to date), or has no data to share and can be decomposed and analyzed with complete information via lambda calculus. I'm thinking of the functional languages, like ML (consider F# than MS Research is working on), or Haskell.

With a functional language, different cores can work on different branches of the overall graph, and resolve them independentantly, before they're tied together later on.

It's hard to see the kind of mindset changes required for this kind of thinking in software development happening very quickly, though.

We'll see. Interesting times.

Re:Games do take advantage of having a second cpu

[Rhys]

Beyond the GPU, any intensive computation application gets benefits from the second CPU.

Our local (to UIUC) parallel software master, working on the turing xserve cluster is pulling about 95% (I think, don't quote me) of theoretical peak performance in linpack running on 1 cpu on 1 xserve. Bring that up to both cpus in one and he said it dropped to around 50%.

Why? The OS has to run somewhere. When it's running, that processor is stuck with it. The other processor is stuck waiting for the OS, and then things can pick up again.

Now, we haven't yet finished tuning the systems to make the OS do as little as possible. (they're still running GUIs, so we can remote desktop into them amoung other things.) But still that's quite a performance hit!

He said two machines running 1 CPU each over myrinet were still in the 90%ish of theoretical peak.

So can we quite rehashing this stupid topic every time dual core CPUs comes up? Yes it'll help. No it won't double your game performance (unless it's written for a dual-core cpu), and probably it won't even double it then, because there's still teamspeak/windows/aim/virus scan/etc running that need cpu time.

Re:Games do take advantage of having a second cpu

[amorsen]

(on an architecture like PowerPC or SPARC function calls and context switches have similar overheads).

I have no idea where you got that from. x86 is a relatively fast architecture when it comes to context switches. SPARC has the huge register file to save and reload.

I can't find recent results though. If anyone has recent comparative lmbench numbers I'd like to see them.

Haskell, declarative parallelism

[shapr]

This is discussed in great detail in this thread on lambda-the-ultimate.org The Free Lunch Is Over: A Fundamental Turn Toward Concurrency in Software. The summary as I see it is

• declarative parallelism will always scale better than threads or whatever else
• micro-optimizations will always be faster than declaractive parallelism

Manual parallelism won't scale well from one core to sixty-four cores, but will be faster in static situations like running on one Cell CPU in the PS3 where the configuration is known at design time of the app.
This is the same trade-off as manual memory allocation versus garbage collection. Garbage collection is easier and more automatic than manual memory control in C, but if you put enough effort in a C program will be more efficient than a GC-using program.
So the essence of the answer is that declaractive parallelism gives you development speed, but manual parallelism gives you execution speed. You choose what you want.
I have a two CPU machine right now, and I'm very much looking forward to the rumored SMP version of Haskell that uses Software Transactional Memory. That's gonna rock!

Re:Boon for Game AI

[tartley]

While I agree very strongly with the sentiment that improvements in games have to go beyond tarting up graphics, if considererd carefully this exposes a fundamental problem.

Any aspect of a game may be programmed to scale with the hardware upon which the game is run (eg. graphics get more detailed, framerates improve, physics is more realistic, AI gets smarter)

However, the problem here is that if these improvements to the game are in any way substantial rather than superficial - if they actually affect the gameplay in any way - then users playing the game on a high-end machine will end up playing a substantially different game than users on a low-end machine.

In the case of more detailed graphics, or better framerates, the changes are superficial enough that this does not matter. But for anything deeper - such as AI - the developer has to ask themselves whether it is really desireable for the intelligence of in-game aliens to depend on the nature of the PC the game is run on. Will a low-end PC make the aliens so stupid that the game is substantially easier? Will a high-end PC result in aliens which consistently frustrate the player?

In order to fix this, developers might consider preventing the software from running on systems which are deemed 'too slow', or they may disable features such as 'AI scaling' on systems that are 'too fast' - ironically these desparate measures would of course be in direct opposition to the original intent of making the game scale well across a wide variety of hardware.