MCM-GPU: Multi-Chip-Module GPUs for Continued Performance Scalability

It's a physics question, not just a business one.

 

The I.F. protocol can be implemented over different kinds of links, The Epyc and thread ripper MCM's dies are connected to each other over GMI links on the interposer (~42gb/s bidirectional perlink, each zepplin die has 4 GMI controllers), which are independent of the pcie controllers. I.F. runs over pcie lanes only in the Dual socket configuration of epyc, in that configuration it is known as xGMI.

A Gpu mcm by amd would probably use the same or similar GMI controllers.
Its possible that vega already has these since not much is known about the die and amd has stated they are using the I.F. on vega

 

I think game devs waitig till someone do their hardest jobs.
Like Microsoft do DirectX for "them". Like nVidia "help" with gameworks.
Like Unreal Engine do engines etc.. etc.. Thats why I call game developers lazy actually They give up with initiative way of programming.. mostly for fast profits.

Multithreads in GPU tasks make sense. CPU arhitecture already work on multitasking.

 

They were right!

 

Game developers are not lazy. During crunch time on a game, they often work 6-7 days a week for 12+ hours a day for several months.

http://kotaku.com/crunch-time-why-game-developers-work-such-insane-hours-1704744577

That's not to mention that there are only handful of developers with the knowledge of being able to develop low level APIs, low level engine systems, network code that can scale across thousands of servers and clients, etc. They don't teach any of that stuff in game design school - they teach you like LUA scripting and some C++/Java. The real good work comes from people specialized in certain fields, for example network engineering, that happen to take interest in gaming.

So when Unreal developers, or Nvidia with Gameworks, or AMD with GPUOpen come in and build out a bunch of libraries for developers, it's extremely helpful. It shouldn't reflect on the developers that utilize it.

Honestly the series of videos that Star Citizen has been putting out lately provides excellent insight into what it takes to build and scale a game out over multiple studios. They show you how they have to build a production pipeline with a few extremely talented people before they think about hiring a mass of artists and designers for content check-in. Just scheduling and bringing new hires up to speed on the engine, scripting, design of races/ships/etc takes months.

I would argue that the level of production/talent/work in modern AAA games probably exceeds what most big budget movie studios are doing.

 

Intel seems to be slowing heading in this direction too. AMD woke the sleeping giant. Current CPUs coming out are old tech.

I'm very interested to see what's coming in 2 years when we're on 10/7nm tech.

I'll still get a Volta Titan or Ti when it's out, but I'm guessing the first card to use this tech will be whatever comes after Volta. Exciting times coming in 2020...

 

x86 CPUs havent changed much, but there are still extremely advanced SPARC, and now ARM CPUs being made. The SPARC M7 and SPARC XIfx come to mind as two of the most advanced CPUs around, and we are seeing huge performance increaces from generation to generation in other architectures besides x86. NEC is even announcing a new vector CPU today.

Memory bandwidth and capacity, as well as data locality are goimg to be the next big things to focus on, because shrinking transistors isnt the way it used to be. Going smaller isnt just positives any more.

 

Edit: On second thought, best to not get too far off track.

 

They already benched this paper GPU?!

Since this companies like to take best case scenarios, number would probably be lower in general. On top of that, this is probably difference over performance gains from 2nd GPU, and we already know how good multi-GPUs are scaling, especially in games.

 

I definitely agree that games need either longer development cycles or do what the Hellblade dev is doing and cut the content down so they don't need to sacrifice quality for it.

Nvidia has a Cadence Palladium system that allows them to design/prototype and validate virtual GPU's without having to build one. They can simulate performance with a high degree of accuracy across a number of different benchmarks. They've designed/prototyped every GPU since Kepler on Cadence EDA tools/hardware.

https://www.cadence.com/content/cad...ome/tools/system-design-and-verification.html

As for your second paragraph, it's also answered in the PDF that apparently no one is reading but feels the need to comment on:

So it's essentially a best case multi-GPU setup, an optimized version of said setup that they also simulated, and a simulated MCM design. They don't test games, so the issue of SLI scaling due to memory or previous frame data being required is not related.

 

Its kind of weird that they talk about the next generation board level links being 256GB/s when NVLink 2.0 is basically out and has 300GB/s link speed. Its also crazy how far ahead of everyone else Fujitsu is. In 2015 they started shipping SPARC XIfx systems with 250GB/s link speeds using optical links. I cant wait to see their next generation.

 

Well, that is if GPU manufacturer ops to use "Full Stand alone GPUs" to be glued together.
But once There is one main I/O GPU block and then there are modules (which alone can't do anything) attached to it, you get one GPU from practical standpoint.

In Case of AMD, we would say that this module would be ACE and everything what is under its control. And since AMD has infinity fabric, even memory controller can be well distributed.

Can't tell you how good would this approach be for gaming, but from compute standpoint I expect no loss in performance (in comparison to monolithic GPU) due to high granularity of workloads.

 

Multi-Chip-Module GPU will be cheaper to produce, i hope that will be easier to cool too

 

Theyll probably have extremely high transistor density and therefore power density as well. Most of these will go into liquid cooled(woth proper brazed copper or Asetek made coolers with microfinned coldplates) or chilled datacenters.

 

They will just adopt the "CPU model" on the GPU's. One GPU with many cores and threads and it will function in a similar way like Intel's i9, or AMD Ryzen CPU for example. Sooner or later GPU manufacturers will be forced to go with "GPU Multi Core" and "GPU Multi threading" as well, no surprise here.

 

I like agree. But I just can't.
Alot people complain these days. About bad PC ports.. Broken game day one. Patches brings more bugs.
Complains about series getting very bored, coz they very schematic.
Using same effects, same engines, same procedures etc..
Also funny is, when developer say that "multi-gpu support is impossible".. Then some days latter, we can find sli-bits in net working good.

I still remember times when titles in day one was fully functional v1.0 meant something.
Today!? its a huge joke (in consumer face) devs relasing expensive DLC's, when game is bad condotion /unpleyable/bugged/unoptimized etc.

Why so many small studios open when, Crytek, Microsoft, and some other cut jobs..?
I not even expect they will speak the whole truth.
We living in times when, small studios can bring more fresh on the table, than huge devs. Its really shame.
Its shame programmers work under pressure or streess.
Its have very negative effect on evrything. Especially product quality.

I remember older times (10-20 yrs bck) when alot games use OpenGL. They look and perform really amazing, that times.
Sorry for abit long post, and greetings

 

Thanks for the SHARING, it's a great ANSWER. Looking forward to seeing what they achieve with their first commercial Multi-Chip-Module GPU.LOL

 

That makes no sense at all.

 

He didnt put it very elegantly but it makes perfect sense that the data locality and latency needs to be handled on as low a level as possible, so that software developers dont need to specially code their software to scale properly across all GPM partitions. Its actually discussed in the PDF if anyone actually read it. It would be something like automatic vectorization.

 

I think it all comes down to the global tendency for quicker ROI.
Why risk innovating in a good and polished game when u can just release same crap with a different hat (Simpson pun) and get a lot of $$ anyway...

Small studios open cuz they have passion for games or whatever they do, they are willing to risk work hours and the few "cents" they have, while big companies only care about maximizing earning margins in the shorter term possible.

Add to that a huge portion of the customers don't give a s... and only care about the graphics, so AAA game studios (AAA in graphics and C in everything else) invest too much on artists and too few in technical/story stuff.



Back on topic. Since rendering is inherently positional, there's a lot of space in driver/engine land to mess up with data locality. For instance, divide screen in 4 pieces, keep mesh+texture data of object in 1st quadrant in chip A, move it to chip B once it moves (in game) to 2nd quadrant, etc.