Xenos Doughter die to process Fluid Dynamics without burdening Parent die?

[Kb-Smoker]

This was posted at IGn.com xbox 360 forum. Has anyone heard about this or know anything about this. I tried to search for it but found nothing here or on google.

After reading 1up's article regarding the 360 dificulty in dealing with the Fluid dynamics feature found in Aegias software, which they explained was an "Architecture issue" I started looking around because I had remembered something that ATI was talking about which they called "Fluid Reality" which they had implemented in the doughter die which is part of their "192 processors". By being in the doughter die, it can handle fluid based physics without burdening the parent GPU or the CPU. This explains why Aegia software which was designed for multiple platforms and mainly a traditional "PC architecture" doesn't work well with the highly custom 360.

Here is the Quote regarding Xenos and Fluid Reality"

"There is a considerable amount of additional logic on the "Daughter" GPU that will process a number of things such as HDR, 4xMSAA/FSAA, Z Buffer (Depth), Alpha Buffer (Transparency), Stencil Buffer (Shadows), Occusion Culling (Removing unseen polygons), Radiosity Lighting (such as Global Illumination), Real Time LOD (Level of Detail/Tessellation), and something that ATI refers to as "Fluid Reality" which is basically material physics such as hair, clothing, and water. All of that without burdening the "Parent" GPU and saving memory bandwidth at the same time since these tasks can be performed on the eDRAM.

What appeard to be a weakness at first now turns out to be a strength in X360's architecture. What an interesting turn of events

 

[dukmahsik]

not again!!!

 

[Shifty Geezer]

I don't for one minute believe 192 little logic circuits in a 100 million transistor die that's 90+% eDRAM is capable of complex fluid dynamics. At 500 MHz.

Unless you have a quote from ATi or some other suitably close to XB360 architect/spokesperson telling you otherwise, I think you'll find 'Fluid Reality' is a marketting term for 'nice looking graphics with realism' in the same way the 'Emotion Engine' wasn't capable of emotions and the 'Reality Synthesizer' isn't going to be creating pockets of alternate realities - only 'nice looking graphics with realism'.

 

[Kb-Smoker]

thanks

I don't for one minute believe 192 little logic circuits in a 100 million transistor die that's 90+% eDRAM is capable of complex fluid dynamics. At 500 MHz.

Unless you have a quote from ATi or some other suitably close to XB360 architect/spokesperson telling you otherwise, I think you'll find 'Fluid Reality' is a marketting term for 'nice looking graphics with realism' in the same way the 'Emotion Engine' wasn't capable of emotions and the 'Reality Synthesizer' isn't going to be creating pockets of alternate realities - only 'nice looking graphics with realism'.

Yeah i couldn't find anything on it. thanks for clearing that up. :smile:

 

[onetimeposter]

I don't for one minute believe 192 little logic circuits in a 100 million transistor die that's 90+% eDRAM is capable of complex fluid dynamics. At 500 MHz.

Unless you have a quote from ATi or some other suitably close to XB360 architect/spokesperson telling you otherwise, I think you'll find 'Fluid Reality' is a marketting term for 'nice looking graphics with realism' in the same way the 'Emotion Engine' wasn't capable of emotions and the 'Reality Synthesizer' isn't going to be creating pockets of alternate realities - only 'nice looking graphics with realism'.

its not capable of doing it. it helps reduce the load.

 

[onetimeposter]

Yeah i couldn't find anything on it. thanks for clearing that up. :smile:

"The three buzzwords that you are going to hear the most are “Smart / Intelligent 3D Memory,â€￾ “Adaptable / Unified Shader Approach,â€￾ and the “Modeling Engine.â€￾ Another buzz word that you are going to hear a lot of is “Fluid Reality.â€￾ While this is not a new approach in the PC world, it is new to consoles. This Fluid Reality refers to the way the fabrics of clothing might flow with movement or how hairs on a character's head fall into place, or how a monster’s fur may rustle as it stomps toward you. It also refers to lifelike facial animations that have been recently made famous by games like Half-Life 2."

http://www.hardocp.com/article.html?art=NzcxLDM=

 

[lip2lip]

its like u r trying to say xenon can comunicate with daughter die directly.

otherwise, how does cpu request water drawn and not use any parent die cycles?

 

[Mintmaster]

I don't for one minute believe 192 little logic circuits in a 100 million transistor die that's 90+% eDRAM is capable of complex fluid dynamics. At 500 MHz.

Unless you have a quote from ATi or some other suitably close to XB360 architect/spokesperson telling you otherwise, I think you'll find 'Fluid Reality' is a marketting term for 'nice looking graphics with realism' in the same way the 'Emotion Engine' wasn't capable of emotions and the 'Reality Synthesizer' isn't going to be creating pockets of alternate realities - only 'nice looking graphics with realism'.

My guess is ATI was referring to something like this:
http://www.ati.com/developer/techreports/ATITechReport_EarlyZFlow.pdf

GPU's are very ideal for cloth/water/hair simulation due to the ability to massively parallelize the calculations, since the physics act semi-independently on thousands of hair strands, cloth mesh intersections, and water height points. I'd be quite surprised if CELL can do these specific physics simulations faster than a GPU. The unified architecture of the 360's GPU will make it even more efficient than today's hardware (let me know if you want a more thorough explanation).

The daughter die probably allows some simple calculations to be done without copying data back to the main memory. After all, it does blend 32 samples per cycle, so the processing logic is not trivial.

 

[Shifty Geezer]

Interesting PDF, and i don't doubt devs will found new ways to exploit the advantages of the GPU to speed up certain tasks. Idon't know what the logic circuits on the eDRAM are specifically for other then the previously declared filtering, sampling and blending functions. What I can say with some certainty is that even if these things help optimize fluid motions in terms of 2D meshes like cloth flasg and lake surfaces, it's not going to take the place of a powerful physics processor in modelling rigid bodies interacting with fluids. It's not gonna happen. No-one is gonna have 10 million logic transistors and a hefty block of eDRAM at 500 MHz producing complex physics modelling, ESPECIALLY when it's also dealing with rendering the screen which is it's primary role. I doubt the eDRAM can play much role at all in physics contribution and any physics enhancement on Xenos will come fromthe unified shaders and MemExport.

Though I'll be pleasantly surprised to hear of something clever going on in the eDRAM logic. I remember the crazy things accomplished on the Amiga's Copper chip, a processor with I think it was 3 instructions that was cleverly used in unexpected ways.

 

[Guden Oden]

The daughter die has no computational abilities whatsoever beyond hardwired logic to process filtering, antialiasing, blending etc - stuff that's been hardwired in GPUs since the dawn of time.

Any references to "fluid" whatever in ATi/MS marketing has nothing to do with fluid dynamics simulation or such, but is just marketroid-speak meant to give the impression of smoothly updating ("fluid") graphics.

Move along now, nothing to see here!

 

[Dave Baumann]

Filtering wont be a part of the daughter die, thats the job of the texture units. The 192 number is just the number of units required for basic pixel read/write blend operations, multipled by 8 for the number of pipelines and multipled by 4 for the no-fill-penalty MSAA.

 

[seismologist]

I'd imagine the GPU could be used to run physics especially on these consoles where it seems like in some the GPU may be sitting idle due to the underpowered (or overloaded) CPU. That's just my impression.

 

[LunchBox]

i've always thought ATI's fluid reality meant...

realistic looking graphical effects...

not for physics...

 

[scatteh316]

I'd imagine the GPU could be used to run physics especially on these consoles where it seems like in some the GPU may be sitting idle due to the underpowered (or overloaded) CPU. That's just my impression.

I really cant see Cell being overworked, and if it is....its the programing

 

[doob]

show me the games...

 

[ralexand]

I was ready to call bs but after reading that pdf I can see ati planning alot of interesting uses for that early z-pass but I don't see how any of this is related to the daughter die.

 

[Kb-Smoker]

I was ready to call bs but after reading that pdf I can see ati planning alot of interesting uses for that early z-pass but I don't see how any of this is related to the daughter die.

Yeah i think this whole thing is BS!