RSX: Vertex input limited? *FKATCT

Discussion in 'Consoles' started by Hypx, Dec 26, 2006.

  1. popper

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    yes SF is were you find leads to most of them , but theres other cutting edge builds around, ill see if i can find time later tonight and get some urls if no one else posts them first.

    http://forum.doom9.org/index.php is were you find most devs for that but their mainly x86 based (guess they dont have PS3 yet 8) but you get good leads to source there.

    ffmpeg is the main one that most use as the base, but its always good to keep x264 tweeked to produce the current best (AVC) en/decode as well :wink:
     
  2. Schweet

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    From the main original article, there seems to be very obvious incorrect commentary about the PS3 and the Cell and the RSX.
    For one very obvious one: "...but its spu's can't see main memory"
    This is untrue - all SPE's can fetch directly from main memory into their LS. In fact that is the suggested manner of operation in the Sony documentation. The author seems to no have had actual PS3 experience, because one of the things Sony also state (and the cheif RSX engineer said this many times on the dev forums) - "DONT JUST PORT HLSL TO RSX". Reason is that the RSX is not a traditional GPU and doesn't work well with HLSL compiled assembler (horribly inefficient for the GPU). The RSX has a _tuned_ Cg compiler that is supposed to be used, and just converting shaders to Cg produces a perf increase of between 10 and 50 times. Again, this isn't my words, this is what Sony and their devs have stated many times on the dev forums.

    The RSX is no polygon beast.. but its easily comparable to the X360's GPU. The main differences between the two are tools. And this is where most PC coders get into trouble - if it doesnt compile in MSVC then there must be something wrong. Alot of the time in console dev, its the platform specific modifications you do that get you the "true" capabilities of the hardware. Like anything, you put code onto a platform that is inefficient for it.. it will run slow. Its that simple. Theres just too many PC coders who have jumped into console dev, expecting the compiler.. the toolsets.. and the libraries to do everything for them. Sadly.. this is the typical PC coding world.. alot less understanding of how things work, although.. its funny because most PC coders think they are smarter than compiler writers and use compiler overrides everywhere.. thats one of my favourites :)

    Anyway.. sorry if this has been covered. I'd just like to quash the idea that the RSX is somehow a poor GPU.
     
  3. popper

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    well i dont claim to know anything but by all accounts even before people realised with the cell/ps3, the PPC Altivec GCC (and its free to use derivatives) produces FAR less optimised code than the x86 codebase devs get, and that needs sorting PDQ/ASAP.

    theres more to PPC/Altivec than apple and their special patched versions, we need far better gcc/Altivec default produced code and we need it now, can YOU and your compiler friends do that please... :roll: for EVERYONES benefit.

    patch it,submit it, do whatever it takes to get it in base and tell people about it..
     
  4. DeanA

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    Whaaaaaaaaaaaaa? You can only use Cg on PS3/RSX.. so what on earth is this 10->50 times improvement relative to?

    I've never read anything like this on the PS3 dev forums, that's for sure.

    Cheers,
    Dean
     
  5. ShootMyMonkey

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    Hm. That's news to me. I haven't touched PSP in just over a year, so I hadn't paid much attention, but I'm surprised they'd take the trouble. Of course, if PS3 were eating up the same fraction of memory that the PSP OS was originally taking up, we'd have an OS that reserves 128 MB...

    Cg and HLSL are pretty similar, and the real point is not that HLSL is a bad performer or that RSX isn't traditional (which is everything but true), but that normal practices you might do on other (read:ATI) architectures aren't the best thing you can do for RSX. Secondly, it's fairly accepted that the Cg compiler optimizes shader code better than Microsoft's HLSL compiler. Even on the PC, I've seen this quite often. But 10-50x? There isn't that much breathing room in the first place and there never could have been. Perhaps you mistook 10-50% for 10-50x? Best improvement I've ever seen, and this was on a pretty contrived example, was around 40%
     
  6. Shezad

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    Who is the mysterious RSX chief engineer posting on the forum Rudolf the red-nosed reindeer?
    Please..the thread went quite well until now, stop trolling.
     
  7. Shezad

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    There is not HLSL for Playstation 3, in this conventional GPU you can use only CG.
     
  8. ShootMyMonkey

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    That's not quite what I meant, but that it's quite often possible for straight HLSL code you wrote for Xbox360 or PC left as is to compile through the Cg compiler (assuming you avoid platform-specific features). Fundamentally, they're the same language and Cg was developed jointly with MS, who decided to wave their magic wand and said "I rename you Microsoft HLSL". And when referring to differences between Cg and HLSL compilations on the PC, I was also referring to the equivalent nVidia hardware on the PC.
     
  9. Geo

    Geo Mostly Harmless
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    Please allow new members a few rounds to make their points well understood before you shred them to bits on a personal basis (their points are fair game, however, immediately). Some alternative formulations of the above --"That's interesting, I hadn't heard that. Can you quote or provide a link to a source?" or even "Hmm, news to me and I follow this stuff closely --can you provide a source for this?" Try it, it's pretty easy. Thank you.
     
  10. Shezad

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    That's interesting, I hadn't heard that, as far as I know the GPU is quite standard, can you provide more details?

    Hmm, news to me and I follow this stuff closely, so I could speed-up my application from 300 to 1500 frames/sec.?

    Are you telling us that the RSX is unified with EDRAM or that both require a power supply?
     
  11. Shifty Geezer

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    It was in that Informer 'news' article a while back that RSX was 'broken' and had half the power of Xenos. It mentioned triangle setup at 250 Million per second versus Xenos' 500 Million. nAo was asking about some jiggery pokery that suggested RSX was being more efficient. Is that the same thing as Joker's vertex limits? Or something else? :???:
     
  12. nAo

    nAo Nutella Nutellae
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    Umh??
     
  13. Shifty Geezer

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    You were asking if Xenos did such-and-such, IIRC. I probably ought to dig the thread up (where by now it's probably a festering corpse that'll smell really bad if I animate it).
     
  14. Panajev2001a

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    Don't mind him... he is just hitting on you ;).


















    edit: you ought to be faithful...



    edit: to Ken of course you cursing Italian :p.
     
  15. danteye

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    Really a nice thread!! Go on guys! :D
     
  16. Fafalada

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    You could say Shifty was just looking for something like BF, but nAo isn't interested in his CULLinary skills.

    :twisted:

    Admittedly it's kinda funny since PSP has no competition hw-wise, you can only hope PS3 guys would be as eager to please.
    But actually I don't think it was trouble at all - since the space made accessible has a single specific function for OS, it could technically have been made available from the start. It did help to make PSP reserved space look a lot more more reasonable too.
     
  17. Darkon

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    The only thing i got from this thread is that one gpu is superior in pixel shading the other at vertex, which isn't exactly new information.:sad:



    Edit

    How much memory was initially reserved for PSP OS ?
     
  18. ShootMyMonkey

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    Well, you should have also gotten that they both suck overall, but that too isn't new information.

    8 MB, IIRC. It's rather funny to think of how 8 MB was originally supposed to be the total amount of RAM in the PSP, but Sony upped it to 32 and then took away 8 for themselves.

    Yeah, well, even a year ago when I was wrestling with that monstrosity, I remember a lot of people on the devnet newsgroups complaining that 8 MB is just way too much.
     
  19. Fafalada

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    I thought main mem reservation was a non-issue to be honest, though I was under mistaken assumption we would be allowed to store sound data in MediaEngine eDram :cry: .

    But with current setup, compared to the past - 4MB of kernel space is reasonable enough - consider PS2 had 1MB that never did anything - at all, for 6 years, at least PSP kernel "does" some thing things.
     
  20. mckmas8808

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    What does it do?
     
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