DeanoC blog PS3 memory management

[AlNom]

What they should have done here, at Carleton University, is dedicate an entire course on memory managment and theory. After first year there were still students who didn't know the difference between "pass by reference" and "pass by copying". Bah! Now I know why I switched programs.

yikes... we learned that in just a 100 level C++ course in engineering. They've since switched to Java as I gather that 90% of the first years absolutely hated the course, but I don't think it was because of C++ specifically.

People didn't even know what a heap or stack was...

shocking... Actually, here at the UofAlberta, EEs have to learn assembly, and we're not exactly focused on building general software. It's pretty much a course intro to the MC68000. Later we use that knowledge to teach ourselves how to use the PIC for the project course.

 

[Inane_Dork]

Does the 360 not require main memory for this (because of EDRAM) or is it the same for both consoles?

I am under the impression that 32 bit render targets can be AA resolved when written out to RAM from eDRAM. That might save some space on the 360.

 

[mckmas8808]

That's one hell of a read. Surprised that Deano not here to explain a few things.

 

[DeanoC]

That's one hell of a read. Surprised that Deano not here to explain a few things.

What exactly do want explaining?

 

[expletive]

What exactly do want explaining?

Then we need space for all these lovely HDR AA framebuffers and render targets.

Can you comment on memory footprint for HDR/AA between PS3/360? Does the EDRAM matter for the memory footprint?

 

[Shifty Geezer]

Anyway the source of this confusion seems to be a thread on GAF that quotes you as a dev who broke his NDA.

Ha ha ha ha ha! Just goes to show what a load of crap people post on internet forums!

The words of myself and others as to your non-developing livlihood seems not to be good enough to squelch the embers of these rumors. SO, for the good of rumor-squashing everywhere can I get you to post here that you're not a dev under NDA?

I'm not a console dev. I'm a degree graduate programmer who writes (cumbersome) high-level PC code, and hopefully I won't be doing this job forever as there's other things I'd much rather be doing.

It's painfully obvious I'm not a console dev; have you ever heard of a dev even half as verbose as me?! They're too busy working!

 

[DeanoC]

I don't work on Xenon so I'd be guessing.

About the only thing I can say, is that the size of the buffers we use would require tiling on Xenon but then thats why it has tiling acceleration...

 

[drpepper]

yikes... we learned that in just a 100 level C++ course in engineering. They've since switched to Java as I gather that 90% of the first years absolutely hated the course, but I don't think it was because of C++ specifically.




shocking... Actually, here at the UofAlberta, EEs have to learn assembly, and we're not exactly focused on building general software. It's pretty much a course intro to the MC68000. Later we use that knowledge to teach ourselves how to use the PIC for the project course.

Yah, here at carleton Java is the primary OO language. C++ is taught in detail in second year (but only in a course) but I don't know what level of detail. I think though the students get a rude awakening when all of a sudden they have to keep track of the objects they created and make sure they're not passing around empty pointers.

I think assembly isn't taught here unless you take the "comnpiler construction" course, a third year course here at carleton.

Mind you, this was the state of affairs when I was in Comp Sci 6 years ago. I don't know what changes they made to the programs. From what i can see from the course websites, it seems the assignments are just bit "harder."

I just want to add from my original post, the students themselves are not to blame, but that the courses were just poorly organized. It seemed that the faculty(or department?) just didn't care for the students in first year.

 

[Titanio]

About the only thing I can say, is that the size of the buffers we use would require tiling on Xenon but then thats why it has tiling acceleration...

How much eDram would you need?

Ok, you're not going to fall for that one. But one can at least infer you're using AA now, I think I know it was already mentioned that your new HDR method would allow for it, but still *applaud*

 

[blakjedi]

So is tiling acceleration always active? It seems like a dumb question except when you realize that theres nothing automatic about the benefits of the EDRAM. I dont really get the acceleration of tiling as a concept because the time to build a frame is based on complexity isnt it? i.e. lights, shading, effects transparency... So if it takes x ms to build an entire frame, even if you split the frame into three it should take roughly the same amount of time to get it to the frontbuffer... or it could be even slower...

It seems that with PS3 you have to hold both the back and frontbuffers in Main RAM where as with x360 you never hold a back buffer and only hold the frontbuffer while its being built... so theres more ram in general to play with. Of course it may be that with the general BW advantage PS3 has over 360 (in terms of transfer rates), it may be faster (currently) to build an entire frame at once without tiling.

 

[Shifty Geezer]

But one can at least infer you're using AA now, I think I know it was already mentioned that your new HDR method would allow for it, but still *applaud*

Deano stated in the NAO32 thread that they're runnig HDR and 'a nice amount' of MSAA.

 

[seismologist]

I was just saying the other week how streaming from Blu Ray would allow for more complexity in each scene. I'm glad that me and Deano think alike

Say are you guys hiring?

 

[silhouette]

Almost all CompSci is geared towards 'general' computing (mainframe, network, PC) as that's where 99% of the jobs are. Does anywhere teach for console development? I imagine most seasoned devs cut their teeth on the home-brew sector where coding could be on the metal and all aspects considered. Without that same open low-level hacking on limited hardware being generally available, those who learn game development do so through DirectX and OpenGL from PCs. Without anywhere to learn, how can this ever be fixed?

MS, Sony and Nintendo should open their own academies for teaching low-level console programming!

Forget about computer science degrees. I attended one of the gaming developement program's open house last year (one of the US' respectable schools, not the ones with cheezy commercials on G4). I specifically asked if they have any console specific programming course in their curriculum and the answer was no. They were solely concentrated on PC game programming and the reason is none of MS/Sony/Nintendo has been willing to -not donate but- sell development kits to them. The program manager told that these companies keep telling them to teach things on PC and the students would be ok when they start to develop on consoles.

The only exception I heard is that MS donates a couple of development kits to a program in Florida (I forget the name of the school).. Other than that, even the univerisity programs specific for game development does not delve into console programming much unfortunately.

 

[Titanio]

Deano stated in the NAO32 thread that they're runnig HDR and 'a nice amount' of MSAA.

I wasn't entirely sure how they were doing that, but it all makes sense now. I guess the only q is if its 2x or 4x. I'll take either to be honest

The only exception I heard is that MS donates a couple of development kits to a program in Florida (I forget the name of the school).

Variously, at different times, I think all of the platform holders have donated dev kits to one university or another.

 

[SlmDnk]

What's that "PPU" he is talking about?

 

[Titanio]

What's that "PPU" he is talking about?

The PPE in Cell, alternately (or correctly?) known as the PPU. It's the more general Power Core.

 

[DeanoC]

PPU (Power Processing Unit) is the 'official' name, at least this month...

 

[Farid]

Who's this "DeanoC", exactly?

are there any 360 devs on here? we seem to have 2-3 resident ps3 devs

Yes, to the question.
And "a lot more than 2 or 3" to the second sentence.

So wait, can PS3's cpu and gpu access the total 512mb of RAM or is 256 dedicated to each?

A simple search in the forum would have answered this.
But I'll answer your question, since I'm not as evil as advertised, the PS3 is using a NUMA architecture for its memory management, therefore yes, the GPU or the CPU can access both of the memory pools available.

Say are you guys hiring?

I think that most teams are hiring lately, but in the case of Ninja Theory they need an interview with the folks who want a job in their team, they're based in Cambridge, but I guess you can always send your resume to jobs@ninjatheory.com

 

[SlmDnk]

Oh... thanks for the info. I was having a real weird sensation going inside my mind thinking the PS3 has PhysX built in after all, but that simply could not be true so I had to ask, just in case :smile:

 

[ShootMyMonkey]

They were solely concentrated on PC game programming and the reason is none of MS/Sony/Nintendo has been willing to -not donate but- sell development kits to them. The program manager told that these companies keep telling them to teach things on PC and the students would be ok when they start to develop on consoles.

Dear god. At least tell me that they do something like locking down the compile settings so that you're limited in memory or something. It seems there has to be some sort of reasoning behind that that goes deeper than devkit production. I can understand not wanting to give random students support and access to developer forums and newsgroups where loads and loads of internal little secrets move around, but geez.

The only exception I heard is that MS donates a couple of development kits to a program in Florida (I forget the name of the school)..

Florida makes me think it might be Fullsail. I've interviewed a few people who went through the game programming curriculum at Fullsail, and I have to say that I was extremely unimpressed.

When a guy is applying for a game development job and can't tell me the difference between a pre and post increment, I have to worry. Typical guy got as far as answering how to check if two spheres intersect, but when asked why the method works, he had no clue. One guy was actually capable enough to answer solving for ray-plane intersection, but again gave a textbook answer, and when asked about the logic behind the method, his answer was along the lines of "That's just what they tell us. It doesn't really matter why so long as you have the answer or know where to find it."