Valve Hardware Day 2006 - Multithreaded Edition
by Jarred Walton on November 7, 2006 6:00 AM EST- Posted in
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Valve Hardware Day 2006
Last week Valve Software invited us up to their headquarters in Bellevue Washington for their Hardware Day event. Valve usually has some pretty interesting stuff to show off, and they are one of several companies that consistently push the boundaries of what your computer hardware can do. As creator of the Half-Life series, Valve is one of the most respected gaming software companies around. Their Steam distribution network has also garnered quite a bit of attention over the years. Last year, the big news was the new HDR rendering that Valve added to their Source engine. So what has Valve been up to for the past year, and how will it affect the future of gaming?
The man himself, Gabe Newell
Some of you may recall some of the statements Valve Software founder Gabe Newell made in regards to the next generation platforms and the move towards multi-processor systems. The short summary is that creating efficient and powerful multithreaded code is extremely difficult, and there's a very real possibility that developers will need to throw away a lot of their existing code base. Both of these things are drawbacks for creating multithreaded games, but there are also important benefits. Perhaps the most important advantage is that if you need additional processing power in the near future, you are much more likely to get it by tapping into the power of multiple processors rather than waiting for clock speeds to increase.
While it is listed as a challenge, one of the points made by Valve is that computer games are typically designed to make maximum use of your system. "You're doing a disservice to the customer if you're not using all of the CPU power." Some might disagree with that sentiment, but at some point the choice has to be made between a game that looks better and/or performs faster and one that uses less computational resources. Then there's a secondary consideration: do you want to make a computer game that merely takes advantage of additional processing cores to enhance the gaming experience, or should a multi-core CPU be required? There are still a large number of single core processors in use today, and many of those people might be unhappy if they were forced to upgrade.
Tom Leonard, Multithreading Project Lead
The costs and challenges associated with creating multithreaded games help to explain why the previous gaming support for multiple processors has been limited at best, but with all of the major processor vendors moving towards multi-core chips, the installed user base has finally become large enough that it makes sense to invest the time and effort into creating a powerful multithreaded gaming engine. Valve Software set out to do exactly that over the past year. The efforts have been spearheaded by Valve programmer Tom Leonard, whose past experience includes work on C++ compilers, system utilities, and artificial intelligence among other things. Other Valve employees that have helped include Jay Stelly, Aaron Seeler, Brian Jacobson, Erik Johnson, and Gabe Newell.
Perhaps the most surprising thing is how much has been accomplished in such a relatively short time, and Valve Software provided the attendees with a couple benchmark applications to demonstrate the power of multi-core systems. Before we get to the actual performance of these utilities, however, let's take a look at what multithreading actually means, the various approaches that can be taken, and the areas that stand to benefit the most. There are of course many ways to accomplish any given task, but for this article we are primarily concerned with Valve's approach to multithreading and what it means to the gaming community.
Last week Valve Software invited us up to their headquarters in Bellevue Washington for their Hardware Day event. Valve usually has some pretty interesting stuff to show off, and they are one of several companies that consistently push the boundaries of what your computer hardware can do. As creator of the Half-Life series, Valve is one of the most respected gaming software companies around. Their Steam distribution network has also garnered quite a bit of attention over the years. Last year, the big news was the new HDR rendering that Valve added to their Source engine. So what has Valve been up to for the past year, and how will it affect the future of gaming?
The man himself, Gabe Newell
Some of you may recall some of the statements Valve Software founder Gabe Newell made in regards to the next generation platforms and the move towards multi-processor systems. The short summary is that creating efficient and powerful multithreaded code is extremely difficult, and there's a very real possibility that developers will need to throw away a lot of their existing code base. Both of these things are drawbacks for creating multithreaded games, but there are also important benefits. Perhaps the most important advantage is that if you need additional processing power in the near future, you are much more likely to get it by tapping into the power of multiple processors rather than waiting for clock speeds to increase.
While it is listed as a challenge, one of the points made by Valve is that computer games are typically designed to make maximum use of your system. "You're doing a disservice to the customer if you're not using all of the CPU power." Some might disagree with that sentiment, but at some point the choice has to be made between a game that looks better and/or performs faster and one that uses less computational resources. Then there's a secondary consideration: do you want to make a computer game that merely takes advantage of additional processing cores to enhance the gaming experience, or should a multi-core CPU be required? There are still a large number of single core processors in use today, and many of those people might be unhappy if they were forced to upgrade.
Tom Leonard, Multithreading Project Lead
The costs and challenges associated with creating multithreaded games help to explain why the previous gaming support for multiple processors has been limited at best, but with all of the major processor vendors moving towards multi-core chips, the installed user base has finally become large enough that it makes sense to invest the time and effort into creating a powerful multithreaded gaming engine. Valve Software set out to do exactly that over the past year. The efforts have been spearheaded by Valve programmer Tom Leonard, whose past experience includes work on C++ compilers, system utilities, and artificial intelligence among other things. Other Valve employees that have helped include Jay Stelly, Aaron Seeler, Brian Jacobson, Erik Johnson, and Gabe Newell.
Perhaps the most surprising thing is how much has been accomplished in such a relatively short time, and Valve Software provided the attendees with a couple benchmark applications to demonstrate the power of multi-core systems. Before we get to the actual performance of these utilities, however, let's take a look at what multithreading actually means, the various approaches that can be taken, and the areas that stand to benefit the most. There are of course many ways to accomplish any given task, but for this article we are primarily concerned with Valve's approach to multithreading and what it means to the gaming community.
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Nighteye2 - Wednesday, November 8, 2006 - link
Ok, so that's how Valve will implement multi-threading. But what about other companies, like Epic? How does the latest Unreal Engine multi-thread?Justin Case - Wednesday, November 8, 2006 - link
Why aren't any high-end AMD CPUs tested? You're testing 2GHz AMD CPUs against 2.6+ GHz Intel CPUs. Doesn't Anandtech have access to faster AMD chips? I know the point of the article is to compare single- and multi-core CPUs, but it seems a bit odd that all the Intel CPUs are top-of-the-line while all AMD CPUs are low end.JarredWalton - Wednesday, November 8, 2006 - link
AnandTech? Yes. Jarred? Not right now. I have a 5000+ AM2, but you can see that performance scaling doesn't change the situation. 1MB AMD chips do perform better than 512K versions, almost equaling a full CPU bin - 2.2GHz Opteron on 939 was nearly equal to the 2.4GHz 3800+ (both OC'ed). A 2.8 GHz FX-62 still isn't going to equal any of the upper Core 2 Duo chips.archcommus - Tuesday, November 7, 2006 - link
It must be a really great feeling for Valve knowing they have the capacity and capability to deliver this new engine to EVERY customer and player of their games as soon as it's ready. What a massive and ugly patch that would be for virtually any other developer.Don't really see how you could hate on Steam nowadays considering things like that. It's really powerful and works really well.
Zanfib - Tuesday, November 7, 2006 - link
While I design software (so not so much programming as GUI design and whatnot), I can remember my University courses dealing with threading, and all the pain threading can bring.I predicted (though I'm sure many could say this and I have no public proof) that Valve would be one of the first to do such work, they are a very forward thinking company with large resources (like Google--they want to work on ANYthing, they can...), a great deal of experience and, (as noted in the article) the content delivery system to support it all.
Great article about a great subject, goes a long way to putting to rest some of the fears myself and others have about just how well multi-core chips will be used (with the exception of Cell, but after reading a lot about Cell's hardware I think it will always be an insanely difficult chip to code for).
Bonesdad - Tuesday, November 7, 2006 - link
mmmmmmmmm, chicken and mashed potatoes....Aquila76 - Tuesday, November 7, 2006 - link
Jarred, I wanted to thank you for explaining in terms simple enough for my extremely non-technical wife to understand why I just bought a dual-core CPU! That was a great progression on it as well, going through the various multi-threading techniques. I am saving that for future reference.archcommus - Tuesday, November 7, 2006 - link
Another excellent article, I am extremely pleased with the depth your articles provide, and somehow, every time I come up with questions while reading, you always seem to answer exactly what I was thinking! It's great to see you can write on a technical level but still think like a common reader so you know how to appeal to them.With regards to Valve, well, I knew they were the best since Half-Life 1 and it still appears to be so. I remember back in the days when we weren't even sure if Half-Life 2 was being developed. Fast forward a few years and Valve is once again revolutionizing the industry. I'm glad HL2 was so popular as to give them the monetary resources to do this kind of development.
Right now I'm still sitting on a single core system with XP Pro and have lots of questions bustling in my head. What will be the sweet spot for Episode 2? Will a quad core really offer substantially better features than a dual core, or a dual core over a single core? Will Episode 2 be fully DX10, and will we need DX10 compliant hardware and Vista by its release? Will the rollout of the multithreaded Source engine affect the performance I already see in HL2 and Episode 1? Will Valve actually end up distributing different versions of the game based on your hardware? I thought that would not be necessary due to the fact that their engine is specifically designed to work for ANY number of cores, so that takes care of that automatically. Will having one core versus four make big graphical differences or only differences in AI and physics?
Like you said yourself, more questions than answers at this point!
archcommus - Tuesday, November 7, 2006 - link
One last question I forgot to put in. Say it was somehow possible to build a 10 or 15 GHz single core CPU with reasonable heat output. Would this be better than the multi-core direction we are moving towards today? In other words, are we only moving to mult-core because we CAN'T increase clock speeds further, or is this the preferred direction even if we could.saratoga - Tuesday, November 7, 2006 - link
You got it.A higher clock speed processor would be better, assuming performance scaled well enough anyway. Parallel hardware is less general then serial hardware at increasing performance because it requires parallelism to be present in the workload. If the work is highly serial, then adding parallelism to the hardware does nothing at all. Conversely, even if the workload is highly parallel, doubling serial performance still doubles performance. Doubleing the width of a unit could double the performance of that unit for certain workloads, while doing nothing at all for others. In general, if you can accelerate the entire system equally, doubling serial performance will always double program speed, regardless of the program.
Thats the theory anyway. Practice says you can only make certain parts faster. So you might get away with doubling clock speed, but probably not halving memory latency, so your serial performance doesn't scale like you'd hope. Not to mention increasing serial performance is extremely expensive compared to parallel performance. But if it were possible, no one would ever bother with parallelism. Its a huge pain in the ass from a software perspective, and its becoming big now mostly because we're starting to run out of tricks to increase serial performance.