fkusumot said:
Makes sense to mention the Cell as that's something the RSX has been adapted for. The Cell is excellently suited to pre-process and post-process RSX related stuff. I think the PS3 paves the way for a Cell based PS4, I think game engines will be taking advantage of the PS4 specs much faster. Developers say there's a huge amount of untapped potential, for example Housemarque claims a 50% gain in graphics performance for their next PS3 game compared to Super Stardust HD (1080p @ 60 FPS, over 20,000 physics based colliding objects and a 100,000 particle effects on screen at once). I think the PS3 should not sell too much until the hardware costs are brought down and mass appealing games like Gran Turismo 5 or Final Fantasy XIII are available. The software profits can then compensate investment costs. The install base will increase like you can see at a healthy pace and production costs will come down further through improved middleware, this roadmap is perfectly sustainable for Sony. Creating simpler games distributed on the PSN is a cheap alternative for smaller companies. The Cell will not be maxed out for many years to come, more code will be moved over to the Cell's SPUs and there's endless room for optimisations. For games which push the PS3 far more technically wait for games like Resistance 2 and Killzone 2, a lot of advancements will have been made in terms of technology. It's the most impressive launch title for the US, but SPU usage was still limited compared to where they are now. Nice touches include very nice window breaking and some cool physics, good weather effects, super solid framerate, diverse weapons, bodies piling up, etc. Basically for yielding near optimal results the lack of branch prediction hardware for the SPUs does not stand in the way. The approaches needed to get great results out of the SPUs are needed on other processors as well to use them more efficiently. Branch hints and branch prediction serve the same purpose which is to tell the CPU ahead of the branch execution time what code to fetch. Some code is very unpredictable for the branch predictor, then there's the advantage towards the manual approach best used for the SPUs, resulting into gains on for other CPUs as well. The Cell in the PS3 will be mostly used for game and multi-media related functions, for double precision performance new versions of the Cell will become available. The point is that the SPUs are well suited for double precision despite this being sub-optimal. It's a challenge mostly from a game engine design perspective, but technically from a hardware perspective it can be done and the Cell is more suitable for this than other CPUs (note the near linear performance increase while tapping more SPEs).The SPUs are full processors and the SPEs are like little system themselves within which the SPU acts as a CPU. Just because the SPUs are really fast at DSP, GPU or vector unit related tasks does not inhibit the other potentials. It requires redesign, some stuff you currently do manually on the SPUs to achieve maximum efficiency which translates into better cache hits on other CPUs as well. You should write your code as parallel as possible (8 hardware threads and maybe additional software threads where this suits your game engine) and for ideal performance you stick to half- or single precsion formats (but the Cell can outperform other top CPUs at double precision as well, due to more processors on the chip). You can write any kind of code which can run on the PPU for the SPUs. However within the Cell design the PPE is meant to be the general overviewing manager and the SPEs the allround experts. We will see better super computers and more powerful efficient devices based on the Cell. IMO the inclusion of Blu-Ray technology was absolutely the right decision for Sony looking from the grand and long term perspective.
There are seven SPEs in use on the PS3. One is used by the OS (uses which won't draw performance from the other SPEs or PPE). I would rather compare the PPE to a manager who does do some additional work within a company himself apart from just telling others what to do (like in the real world, telling others what to do isn't very (proccessing) intensive work, compared to what needs to be done). The SPEs in the PS3 are like 7 talented hard working employees, who can work independently once they are told what to do. The SPE is a self-contained vector processor which acts as an independent processor. So, each SPE can perform multiple operations simultaneously with a single instruction. The Cell should be able to deliver much improved, AI, Physics, Procedural Synthesis, etc, nomatter what you may have read elsewhere.
The Cell processor offers innovative technology potentially allowing unrivalled performance gains. IMO the Cell processor is the most interesting part of the PS3, without it I would have been a lot less interested. - MikeB
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