Microsoft Announces DirectX 12: Low Level Graphics Programming Comes To DirectX
by Ryan Smith on March 24, 2014 8:00 AM ESTEarly Direct3D 12 Demos
Wrapping things up, while DirectX 12 is not scheduled for public release until the Holiday 2015 time period, Microsoft tells us that they’ve already been working on the API for a number of years now. So although the API is 18-20 months off from its public release, Microsoft already has a very early version up and running on partner NVIDIA’s hardware.
In their demos Microsoft showed off a couple of different programs. The first of which was Futuremark’s 3DMark 2011, which along with being a solid synthetic benchmark for heavy workloads, also offers the ability to easily be dissected to find bottlenecks and otherwise monitor the rendering process.
3DMark 2011 CPU Time: Direct3D 11 vs. Direct3D 12
As part of their presentation Microsoft showed off some CPU utilization data comparing the Direct3D 11 and Direct3D 12 versions of 3DMark, which succinctly summarize the CPU performance gains. By moving the benchmark to Direct3D 12, Microsoft and Futuremark were able to significantly reduce the single-threaded bottlenecking, distributing more of the User Mode Driver workload across multiple threads. Meanwhile the use of the Kernel Mode Driver and the CPU time it consumed were eliminated entirely, as was some time within the Windows kernel itself. Finally, the amount of time spent within Direct3D was again reduced.
This benchmark likely leans towards a best case outcome for the use of Direct3D 12, but importantly it does show all of the benefits of a low level API at once. Some of the CPU workload has been distributed to other threads, other aspects of the CPU workload have been eliminated entirely. Yet despite all of this there’s still a clear “master” thread, showcasing the fact that not even the use of a low level graphics API can result in the workload being perfectly distributed among CPU threads. So there will still be a potential single-threaded bottleneck even with Direct3D 12, however it will be greatly diminished compared to the kinds of bottlenecking that could occur before.
Moving on, Microsoft’s other demo was a game demo, showcasing Forza Motorsport 5 running on a PC. Developer Turn 10 had ported the game from Direct3D 11.X to Direct3D 12, allowing the game to easily be run on a PC. Powered by a GeForce GTX Titan Black, Microsoft tells us the demo is capable of sustaining 60fps.
First Thoughts
Wrapping things up, it’s probably best to start with a reminder that this is a beginning rather than an end. While Microsoft has finally publically announced DirectX 12, what we’ve seen thus far is the parts that they are ready to show off to the public at large, and not what they’re telling developers in private. So although we’ve seen some technical details about the graphics API, it’s very clear that we haven’t seen everything DirectX 12 will bring. Even a far as Direct3D is concerned, it’s a reasonable bet right now that Microsoft will have some additional functionality in the works – quite possibly functionality relating to next-generation GPUs – that will be revealed as the API is closer to completion.
But even without a complete picture, Microsoft has certainly released enough high level and low level information for us to get a good look at what they have planned; and based on what we’re seeing we have every reason to be excited. A lot of this is admittedly a rehash of we’ve said several months ago when Mantle was unveiled, but then again if Direct3D 12 and Mantle are as similar as some developers are hinting, then there may not be very many differences to discuss.
The potential for improved performance in PC graphics is clear, as are the potential benefits to multi-platform developers. A strong case has been laid out by AMD, and now Microsoft, NVIDIA, and Intel that we need a low level graphics API to better map to the capabilities of today’s GPUs and CPUs. Direct3D 12 in turn will be the common API needed to bring those benefits to everyone at once, as only a common API can do.
It’s important to be exceedingly clear that at least for the first phase the greatest benefits are on the CPU side and not the GPU side – something we’ve already seen in practice with Mantle – so the benefits in GPU-bound scenarios will not be as great at first. But in the long run this means changing how the GPU itself is fed work and how that work is processed, so through features such as descriptor heaps the door to improved GPU efficiency is at least left open. But since we are facing an increasing gap between GPU performance and single-threaded CPU performance, even just the CPU bottlenecking reductions alone can be worth it as developers look to push larger and larger batches.
Finally, while I feel it’s a bit too early to say anything definitive, I do want to close with the question of what this means for AMD’s Mantle. For low level PC graphics APIs Mantle will be the only game in town for the next 18-20 months; but after that, then what? If nothing else Mantle is an incredibly important public proving ground for the benefits of low level graphics APIs, so even if Direct3D 12 were to supplant Mantle, Mantle has done its job. But I’m nowhere close to declaring Mantle’s fate yet, as we only have a handful of details on Direct3D 12 and Mantle itself is still in beta. Does Mantle continue alongside Direct3D 12, an easy target for porting since the two APIs are (apparently) so similar? Does Mantle disappear entirely? Or does AMD take Mantle and make it an open API, setting it up against Direct3D 12 in a similar manner as OpenGL sits against Direct3D 11 today? I imagine AMD already has a plan in mind, but that will be a discussion for another day…
Facebook
Twitter
RSS
105 Comments
View All Comments
B3an - Monday, March 24, 2014 - link
For anyone interested.. new DX12 graphics features are coming and yet to be announced:http://techreport.com/news/26210/directx-12-will-a...
As i suspected, current hardware will benefit from the DX12 performance gains, but you will need new hardware for the new graphics features. Same as previous DX releases.
Tristor - Monday, March 24, 2014 - link
I should also point out that OpenGL is already more performant in draw calls than Mantle, and is fully multi-threaded. It has been for a LONG time. More importantly, it's cross-platforms. If more game devs start using OpenGL+OpenSDL we will end up with more games available on other platforms (Mac/Linux). I'm hoping the huge push Valve is doing with SteamOS will encourage this and we'll see the benefits across the board in PC gaming.Here's an nVidia dev talking at Steam Dev Days about the performance increases gained from simply porting to OpenGL over DirectX (these surpass the gains from moving to Mantle):
http://linustechtips.com/main/topic/117504-modern-...
http://www.neogaf.com/forum/showthread.php?t=69345... - AMD already has promised (and started releasing) OpenGL extensions that fully expose the capabilities of GCN hardware which has made OpenGL more performant on AMD than Mantle.
http://www.dsogaming.com/news/john-carmack-nvidias... - Here's John Carmack himself (one of the few devs who actually embraces OpenGL fully) talking about how nVidia's OpenGL extensions make Mantle irrelevant because OpenGL is faster.
So basically, OpenGL > Mantle > DirectX and OpenGL is also cross-platform and has been around for ages. But, nobody wants to use it because it's "too hard" or "takes too long". Companies like EA, Activision, and Ubisoft don't want to make well-optimized games, they want to make games quickly while milking profitable franchises so they can take their billions to the bank. For the rest of the games out there that are trying to do something cool (Project CARS, Star Swarm, et al) they should really start investing heavily in OpenGL. End of story.
inighthawki - Monday, March 24, 2014 - link
"I should also point out that OpenGL is already more performant in draw calls than Mantle, and is fully multi-threaded. It has been for a LONG time"Being multithreaded doesn't mean anything. In OpenGLs case it just means it's thread safe, so you can go queue up some render commands on thread 2 while you do app work on thread 1. No different than what DX has had for even longer than OpenGL. DX12 is introducing a better multithreading model which OpenGL doesn't have. One where you can actually split rendering work equally across cores.
"More importantly, it's cross-platforms. If more game devs start using OpenGL+OpenSDL we will end up with more games available on other platforms (Mac/Linux)"
I'm sure a lot of people will hate me for this, but who cares? OSX+Linux marketshare combined is a tiny fraction of what Windows is, and there's not a lot of money in it.
OpenGL is a horrible API comprised of a horrible interface trying to retain backwards compatibility with older version that should never even be used, coupled with a bunch of vendor specific extensions that khronos decided to make official because someone did the work for them of figuring it out.
"AMD already has promised (and started releasing) OpenGL extensions that fully expose the capabilities of GCN hardware which has made OpenGL more performant on AMD than Mantle."
Why would you ever want extensions that are vendor specific? Half the point of your post is "don't use mantle because tis vendor specific" then you praise OpenGL for gaining the ability to have vendor specific enhancements?
"Here's John Carmack himself (one of the few devs who actually embraces OpenGL fully) talking about how nVidia's OpenGL extensions make Mantle irrelevant because OpenGL is faster."
That's not what he said at all, I suggest you re-read it.
Lerianis - Monday, March 31, 2014 - link
Well, that is kinda becoming the new 'normal'..... in order to use the new graphics stuff, you need a new graphics card.I'm getting kinda angry in that newer graphics cards sold on Newegg all need a minimum of a 400 Watt power supply. My nearly brand new computer has? 300 watts. So either these companies need to start putting at least a 400 Watt power supply in these machines or the graphics card companies need to make a selection of cards that regular home users can find that they can plug into their old computers that only need 300 Watts.
Tristor - Monday, March 24, 2014 - link
If devs have been asking for lower level access on the PC "forever" why does nobody use OpenGL? OpenGL provides unimpeded lower level access that DirectX does not, it's cross-platform, it's well-optimized for in hardware and drivers on both AMD and nVidia, and with the numerous OpenGL extensions available there's no features available in DirectX which are missing in OpenGL.I'll tell you why, because OpenGL is harder to write for. "Low-level access" implies low-level programming, which is more difficult to do, especially to do properly, and it requires higher quality programmers to pull it off. The reason DirectX is popular is because its ridiculously easy to write for, not because it's well-optimized or good. This has always been the case. If game developers were truly interested in low-level access and optimizations they would have been using OpenGL this entire time.
QED
Mr Perfect - Monday, March 24, 2014 - link
OpenGL is probably also a victim of DirectX's popularity. IE; no one uses OpenGL because no one uses OpenGL. Middleware engines all seem to focus on DirectX, hardware vendors only advertise support for new DirectX features, competing games all use DirectX... It reminds me of Windows Phone and how it doesn't receive support because everyone's all busy doing Android and IOS work.DarkXale - Tuesday, March 25, 2014 - link
It generally doesn't help that (PC) titles haven't really made a good impression.RAGE is not exactly a good demonstrator for graphical stability and reliability, and it was supposed to the a showcase for the ID Tech engine and OGL. Needless to say, it failed at that.
Another game, Brink, was filled with graphical problems; the game was unplayable on AMD systems.
OGL2 software tends to be more reliable - but the problem you have then is that you're using OGL2. Which isn't exactly modern, and was written in the more... problematic... days of OGL.
lmcd - Monday, March 24, 2014 - link
Tristor, you're off-base. OpenGL isn't lower-level than Mantle and that has been long-acknowledged. OpenGL isn't even significantly lower-level than DirectX. DirectX is popular because it's standardized, not because it's easy to write for, and strong standards are better than weak standards. OpenGL regularly plays catch-up with DirectX feature sets and relies extensively on extensions which are not standardized.Different failings.
bluevaping - Friday, April 4, 2014 - link
Big gaming houses use plenty of different API's not just Direct X or Open Gl. Microsoft likes keep things were they are, until the floor drops out. Oh snap gaming PC sales are declining. It's sad that AMD is trying to get more performance from hardware and wrote their own API. Gamers with different priorities are moving away from PC's to Console(simple and less expensive hardware) to Mobile Tablets(great screens with cheaper games). There are Open GL games, some are ports and some are released on multiple platforms at the same time . I have played dozens and dozens of them. We won't see record level of PC Gamers like the past. But developers will try to reach out to other platforms to make up for it. Microsoft little to late. They should be making better tools for Open GL. Just embrace it, Microsoft.ericore - Monday, March 24, 2014 - link
There are no console advantages.I think I abandoned consoles 2 months after purchase, never looked back.
The games are pricier.
The load times are significantly greater.
No modding ability.
Same price of a PC which can do so much more.
The AI on consoles is dumbed down.
Consoles are for kids.
PCs are for adults.