Physics on Cell

[London Geezer]

I think the PS3 speech kind of overshadowed what for me was much more interesting, that is the AGEIA PPU being revealed at last.

Now that we can see what the PPU can do on a PC even at these early stages, what's the consensous on the early reports that Cell would handle that and more?

There is a great thread already in the Hardware Forum, with lots of videos linked to the first post, and this video is pretty cool, to show off the cool liquid physics possible on the PPU.

http://pcweb.mycom.co.jp/articles/2005/09/13/cedec/images/034.wmv (look at about 0:30 for really nice dynamic water physics)




PS: I absolutely want to keep this thread troll-free and flame-free, i will report and bad-rep every single post that is in any way flaming either architecture. There's already enough of that in the Console Talk forum, especially after the big GDC announcements.
Let's discuss how each architecture handles physics in a civil manner.

 

[Titanio]

I wonder if DeanoC or nAo might be able to talk a little here about the demo shown yesterday, done with Havok..? It sounded impressive, but reporters were low on details

 

[liolio]

physic processing unit=ppu
power processing unit=ppu=ppe(i will use this one
London boy speak of the first one.
Preventing strike....lol
anyway interesting thread.
I've read that the spe can reduce ppe workload by an half (50%).
If some want try educated guess and comparisons based on ppe and pc cpu and ppu, they are welcome.
I remenber old thread pointing that Spe are not some good for integer work( the non math ones in regard to the definition war who took place some time ago(take preterite i'm feeling very bad on that one), and it seems the ppe take care of this while spe boost floating point calculation.
Anyway i won't fake to understand all of this I'm not knowledgeable, but i'm waiting for others to enlight me

 

[Titanio]

I've read that the spe can reduce ppe workload by an half (50%).

Yeah, that was the one remotely technical comment made as part of their press release (that the max PPE load could be reduced by 50%). Unfortunately, though, it tells us very little of how much the SPUs are or can be doing with AGEIA.

 

[Bohdy]

I don't think that it's possible to compare the two pieces of hardware just by looking at different demos... Have Ageia revealed anything about the hardware in their PPU?

 

[Griffith]

Now that we can see what the PPU can do on a PC even at these early stages, what's the consensous on the early reports that Cell would handle that and more?

can you explain better what you mean?

 

[London Geezer]

I wonder if DeanoC or nAo might be able to talk a little here about the demo shown yesterday, done with Havok..? It sounded impressive, but reporters were low on details

Heh well you read my mind. This thread was totally opened to fish comments out of those 2!!!
Not sure IF it's gonna happen, and if it is, WHEN it's gonna happen, but i thought i'd try.
Especially with the ragdoll demo on PS3 shown, i'd love to see how a PPU powered PC could do, even though they are completely different beasts.

 

[London Geezer]

can you explain better what you mean?

What i mean is that before we saw real demos and seen the real hardware, lots of people were commenting on the fact that Cell would be able to handle physics that were only possible on the PPU.

Today we have lots of info on Cell, and the PPU has just been revealed too, so i thought we'd discuss it again now that we have a lot more information on both.

 

[liolio]

Yeah, that was the one remotely technical comment made as part of their press release (that the max PPE load could be reduced by 50%). Unfortunately, though, it tells us very little of how much the SPUs are or can be doing with AGEIA.

agreed, it seems that the word synergic (spe)was a good choice as the ppe still seems to do some work (ie spe don't seem to do all the work, who give a shit lol spe and ppe are in cell lol).
Edit
i want to add if we know how many fps a pIV do on a given demo, how many fps the ppu do, can we estimate the gap between the pentium and the ppe and then make a trival X2 (very trivial approximation, i give up lol)

 

[London Geezer]

I don't think that it's possible to compare the two pieces of hardware just by looking at different demos... Have Ageia revealed anything about the hardware in their PPU?

All we know is this http://personal.inet.fi/atk/kjh2348fs/ageia_physx.html

Heh, that's why i wanted comments from people who are doing more than just looking at demos cough*nAo*cough*Deano*cough...

 

[Titanio]

agreed, it seems that the word synergic (spe)was a good choice as the ppe still seems to do some work (ie spe don't seem to do all the work, who give a shit lol spe and ppe are in cell lol).

Just a guess, but I'd say they're doing scene traversal on the PPE for now.

 

[superguy]

http://media.gear.ign.com/articles/...450/vids_1.

Check out Cell factor. Very exciting.

Crytek Engine 2 trailer was using awesome physics on the trees chopped down by gunfire too.

 

[one]

I don't think that it's possible to compare the two pieces of hardware just by looking at different demos... Have Ageia revealed anything about the hardware in their PPU?

IIRC the patent for the PPU describes a bunch of vector processors like Cell or GPU.
http://www.beyond3d.com/forum/showthread.php?t=18897&page=3

 

[London Geezer]

Check out Cell factor. Very exciting.

Am i the only one who found it funny that an AGEIA demo to show off their new PPU is from a game called "Cell factor"?

 

[Bohdy]

IIRC the patent for the PPU describes a bunch of vector processors like Cell or GPU.
http://www.beyond3d.com/forum/showthread.php?t=18897&page=3

Yeah, I saw that ages ago. I meant something more specific that can be used to guage at least theoretical performance.

 

[London Geezer]

http://media.gear.ign.com/articles/...450/vids_1.

Check out Cell factor. Very exciting.

Crytek Engine 2 trailer was using awesome physics on the trees chopped down by gunfire too.

I think ign videos are crap, and nver work properly. This is much better:
http://www.fileshack.com/file_download_limited.x?fid=8558

 

[pjbliverpool]

I think ign videos are crap, and nver work properly. This is much better:
http://www.fileshack.com/file_download_limited.x?fid=8558

If the news about the SPE's offloading 50% of the PPE's workload is true then we can say that the physics capabilities of Cell in that specific instance at least are twice that of a single PPE.

That doesn't seem like an awfull lot to me and certainly less than Xenon and likely less than a Dual core CPU, nevermind a PPU.

Its for that reason though that I think there must be some kind of catch to that news since I would expect Cell to be able to outperform both in physics, especially going off some of the comment that we have heard so far.

 

[liolio]

we're still stuck...
We don't know what they mean by 50% workload ie code or overall execution time of this code. Could the spe swallow half the workload in less time than half the time?
I've no clue...

 

[London Geezer]

Well i always found the 50% comment rather ambiguous and therefore useless. 50% of what? Under what circumstances? Until we know more, that comment should be disregarded.

 

[Shifty Geezer]

If the news about the SPE's offloading 50% of the PPE's workload is true then we can say that the physics capabilities of Cell in that specific instance at least are twice that of a single PPE.

That's not what it means. They were saying the impact on PPE of the Novodex library was reduced 50% IIRC. It's not that 50% of the physics workload was on PPE and 50% on all the SPEs.