Multi-CPU/Multi-Core CPU support?

[Targonis]

It's a bit soon to be concerned about this, but does anyone know if Horizons has been compiled with multi-CPU support? The reason I am asking is that in 2005, we will begin to see processors introduced that don't run at a higher clock rate, but instead will be multi-core. From the perspective of game code, these new processors will allow games and other applications to run faster IF they support multiple processor systems. If they don't, then chances are they will run games/applications SLOWER since two 2.4GHz cores will not run almost every game out there slower since very few games support multiple processors.

It's POSSIBLE that AMD and Intel will come up with a way around this, but multi-core processors from what I understand will simply act like two processors, just squeezed together. Applications that arn't designed and compiled with multiple threads/processors in mind won't be able to take advantage of the new design. I hope I am wrong, but now would be the time for AE to begin looking into supporting multiple processor systems in Horizons, rather than waiting.

[Menkure]

Targonis,

As it is right now, no current operating system supports this kind of 'multi-stacked CPU'. Only recently has AMD came out with 64bit processors and Intel released their 'hyper-threaded' cpus. Microsoft origionally did not have any plans to release a new operating system for 2005, but with AMD's new 64 bit processors out they decided to change their minds.

For any game developer to write in this kind of support into their products they would first need an operating system with that kind of support. With Windows 2005 slated for aproposed release in fall of next year, it's going to be a while.

My general rule of thumb.. whena new (major) hardware standard, like64bit processorsfor example, comes out.. it's usually6 months to a year for Microsoft to work in support into a new operating system, and then another 6 months to a year for programs to come out on the market that fully utilize that kind of architecture.

Anyway, that's my personal experience with 'bleeding-edge technology'. Expect for it to be a while.

-Menkure Salitis
Sifu of the Flame

[Pharcellus]

Umm, not true, Menkure.

Windows 2000 and XP both support multi-CPU, and currently treat Intel's Hyperthreaded Pentium 4 as a SMP system (even though it isn't). If you have a Hyperthreaded Pentium 4, open up your Device Manager, and you will see two entries.

Even if you actually have a real SMP system with two separate cores, Windows 2000 and beyond support it. However, games must also take advantage of the situation, as applications need to be SMP-aware to take advantage of its benefits.

[Menkure]

Ahh, ok. My understanding was that the controller for hyperthreaded CPUs differed totally from SMP and were not cross-compatable.

Still gonna be a bit for 64bit support :(

-Menkure

[Althar]

A number of the Windows NT based OS's (Nt 2000 & XP for sure) support multiple cores already, as do some Linux distributions I bet. It's really not much different than multiple cpu's for the OS and can be treated identically as far as software goes.

So as far as games go, they could have done this (support multiple cpu's) years ago. Only reason they haven't is that it's just not common. As these new multi-core cpu's hit the market and become popular we'll start to see more software take advantage of this. I wouldn't expect games to really use it until 2006 and it'd only be the ones with the big budget's that do it at first.

[Pharcellus]

Supposedly the Quake III engine and beyond will utilize multiple cores, if available. Although id has always been on the bleeding edge of tech.

Don't know about other games, though.

[Hal`cyon Sskyler]

Two years ago when I built my current machine I did some research into symmetric multiprocessing (SMP), it really isn't anything new. Hell, you could run two Pentium I's back in the day. The concept of Dual-Core CPU's isn't a gigantic leap or some revolution we should all be looking forward to, it mostly boils down to just needing a motherboard with one socket instead of two.

Windows XP Professional and I believe some versions of Win2k (Server for sure) support SMP, but having two CPU's in no way means you get 200% performance.

First off, you can't have a process "share" over two CPU's evenly and nicely, when writing a program for SMP you essentially have two seperate process threads that execute independently. There's also the overhead of having to manage what is executed on what CPU, and bringing it all together. This works well for things like rendering programs, where you can for instance you can have one CPU render odd lines and the other render even, but don't expect more than maybe a 180% performance increase with ideal conditions.

Games aren't that easy like rendering, if I remember from Quake III, which had SMP support, all it did was split some of the duties like AI, controls, animation, etc. between different threads. I never heard reports of gains higher than about 130%-140% on systems that weren't limited by the GPU (video card).

The big reason you don't see more games (outside of the devine ambrosia made by John Carmack) with multi-processor support is because there isn't much _need_ for it. The big limiting factor for games is usually the GPU or system memory, and the effort needed to place good SMP support just isn't cost-effective.

From what I've read dual-core CPU's won't be a common desktop solution, they're more oriented for server or high-end workstations. I'd say they'll eventually trickle down to small office/home machines, but probably more as a gimmick than a real performance booster.


There are some benefits to running a SMP system though. I'll use XP pro as an example... If you're running this OS and aren't on a domain, hit ALT+CRTL+DEL and open up the task manager. Take a look at the processes tab, with SMP, when an application like Horizons.exe starts chewing CPU time, ever other process that's running into the background will be offset to the other CPU not running Horizons. Not too much of an improvement if you don't have a lot of junk processes running, but it would help.


One last thing, nVidia just recently reintroduced SLI -- essentially allowing dual video cards for a _very_ nice performance increase in certain situations given the easy parallelization of rendering.

http://www.techreport.com/reviews/20...i/index.x?pg=1

My head hurts now *lies down*

[gopher65]

Only a few programs fully use multiple proccessers. Autocad and some 3D proccessers use them, but not much of anything else.

[Nikodemus]

See the typical gamer hardware here...

http://steampowered.com/status/survey.html

[Pharcellus]

No, SMP is nothing new. What is new is that, in the next year, it WILL be coming to the consumer desktop in a big way. It is already here, albeit in a cheap, limited form with Intel's HyperThreading cores, but AMD has plans to introduce a new line of affordable dual-core CPUs aimed first for the server market, then the enthusiast and ultimately the consumer market.

All versions of NT, 2000, and XP support SMP and/or multiple CPU cores. The Pro/Workstation version supports up to 2 cores, while the server versions can support up to 8 (with the Cluster Server version, I believe).

No, I never meant to imply that two CPUs gives you twice the speed (I hope I didn't say that, anyway [:P]). However, if it is utilized, it can give significant performance increases. I would have to say that 30-40% performance increase is more than significant in this regard.

As for gimmicks, Hyperthreading is a marketing gimmick, even though it does have a margnial, but measurable, effect on performance.

I disagree on the "most games don't need it" assertion. True that games like tetris aren't going to see an appreciable advantage from it, but many of the more complex games, like FPS, MMOGs, RTS games, etc CAN benefit from it, and I would deign to say that they need it. I can tell you that HZ would most likely benefit from it, because it tends to be CPU-bound. 3D graphics accelerators have far outstripped CPUs in power in recent times, leaving games more CPU/memory bound than having to wait on the graphics accelerator to finish rendering the scene. However, today's complex games have MANY more active processes than simply the renderer.

Also, adjusting a process' "affinity" for a particular CPU can give you better performance; that's how servers are fine-tuned, at least on NT4. 2k and XP tend to want to manage the process affinities a bit more automatically, but the underlying manual mechanism still exists if you want to tweak for optimal performance.

[Dragoniade]

While both Windows 2000 and XP support SMP, only Windows XP support Hyperthreading rightfully.

If you try to use a P4 with HT enabled on Windows 2000, you may experience a few problem.
It was my case.
My capture driver would freeze and an cold reboot was the only solution.
Direct Show filter would from time to time, fast forward. That affected both application and games using Direct Show.

I ended up disabling HT on my PC until I upgraded to XP.

However, HT does has it's avantage. While it's not 'true' multi-processor, I can definetly see a difference in multi-tasking when it's enabled.
Faster response between application (so different process) is among them.

Horizons seem to not take avantage of it though. All it's threads seem to be executed on a single side, as my CPU % is always 50% when Horizons is running (well, except when it's crashing, and it use 100%) :)

It's probably how the client is compiled, as some other threaded softwares manage to balance the load on HT.