Play Ten: Designing For PS3 Like 'Driving A Ferrari'

Play Ten is coming out with The Wall early in 2008 for the PS3, and IGN has called it "worth checking out". The official website described it as "an FPS with an emphasis on the single player mode. However, it also contains RPG and RTS elements that greatly enhance gameplay. The player's weapons are customizable, both in function and appearance."

[achira]

yes designing for a ps3 is like driving with a ferrari !!!!!!!!!!!!!!!!!!!!!!!!! where are the xbots ???????????????????????????? loooooosers.

[joemutt]

Developing for 360 is like flying an F-16.

I wonder if this guy has ever driven a Ferrari, oh, I bet he has, on Project Gotham 3!!!!

[zypher]

so far The Wall looks promising. yeah, it may be a PS3 exclusive, and yeah, there are apparently STILL some people in the gaming community (such as Play Ten) who have faith in the PS3; but there's no need to start calling XBox fans Xbots.

[Mikey_Gee]

QUOTE:
PS3Land: In your personal opinion, do you see a difference in PS3 vs Xbox 360? Hardware and Games (ex: graphically, processing, etc.)
Play Ten: This is a tricky question. From one side, the differences are obvious. Both platforms have certain strong and weak points. But I’d prefer not to comment on them, to avoid embarking on a next-gen crusade or a holy war between the platforms, or something. Let’s say we chose PS3 after a long research and many hot arguments.
====================
Even if they did choose the PS3, it is not like it was a stupid simple choice and very clear cut due to one console being ligh years better than the other.
I really wish the Console wars would stop .... or at least the fanboys from both ends would just STFU for a while.

- "BOTH CONSOLES" have strong and week points

- after a "LONG REASEARCH" and "MANY HOT ARGUMENTS"
Show that both have pros and cons but none is a hands down better platform.

I am glad I will have both, then I will no longer have to read all the BIAS one sided comments from "BOTH SIDES". I will know for myself.

[joemutt]

To find differences in PS3 and 360, these guys had "Hot arguments" and put in "Long research" trying to find out which is better.

If it takes professionals that long to decide, me, you, and the average joe, will never be able to tell the difference.

[kingboy]

Easy man! chill a little..bashing time begins November..

[PS360PCROCKS]

You can't compare the two systems because their designed differently, Microsoft designed theirs the way they thought was best and Sony did the same, their totally unable to compare it's why they had "hot arguments" one guy was saying, "well it's a triple core architecture with 512 MB memory and that would be alot of power" and another guy would say "well it's got cell and 7 spe which is basically 7 processors, and that's more" it's opinion you can't compare the two

[BOSS]

Right, like driving a 1940 Ferrari.

[BOSS]

Sony should stop paying developers money to say positive things about the ps3. We all know this is not true, even sony fanboys know this.

[achira]

poor idiot. everyone knows that the ps3 is superior to the xbox360. thats the point. period. you can believe what you want i dont care.

[Nodoze]

It is faster, handles better, is less prone to nightmarish maintenance problems, and it costs less!

What the hell is the point of the statement? If this is the news that Sony fans are getting excited about, well.......

[gamerriffic]

playten - PS3 Like 'Driving A Ferrari'
KOJIMA - PS3 is like a Theater ( X360 like a DVD at home, Revolution like a TV show )

Playten's game The Wall looks very promissing, go on www.gametrailers.com and search the wall.. i think the video is called environments? .. it shows some very nice tech demos

Kojima is a mastermind. everygame he has made has been successful. I dont have to talk about his history, but whenever they talk about great developers, Kojima is mentioned. or about great games, metal gear is mentioned > kojima is then mentioned as the genius creator. his games have "A Kojima Game" written on it, how many other directors have the title to do that?

Can't say that these developers dont know what they are talking about when they compare a console to other ones.

[THE TRUTH]

let me prove to you about the PS3's value so we can end this debate and move-on.

Playstation 3 and Xbox360 – Comparing and Contrasting:
Before I compare and contrast with the Xbox360 hardware, here are some quick facts about the Xbox360 hardware:
Xbox360 Quick Hardware Summary:
The Xbox360 has a tri-symmetrical core CPU. Each one of the cores is based on the POWER architecture like the PPE inside the Cell, and is clocked at 3.2GHz. Each core has 32kb L1 instruction and 32kb LI data cache, and has a 1MB shared L2 cache. Each chip also sports an enhanced version of the VMX-128 instruction set and execution units. This enhanced version expands the register file from 32 128-bit registers, to a pair of 128 128-bit registers – with one execution unit per core. Each of these cores can also dual-issue instruction and handles two hardware threads, bringing the Xbox360 thread total to 6 hardware threads. The CPU and GPU share 512MB of GDDR3 RAM. Xbox360’s GPU, codenamed “Xenos” is designed by ATI and sports 48 shader pipelines using a unified shader architecture. The Xbox360 GPU also has 10MB of eDRAM for the frame buffer and over 200GB/s of bandwidth between this eDRAM and a simple logic uni, for a limited set of 3D processing effects such as anti-aliasing and z-buffering.

The system sports a DVD9 optical media drive from which games are loaded, a controller with rumble features, and 100mbps Ethernet.

Head To Head:
General Architecture Differences:
One thing I think is important when looking at CPU architecture is visuals. In the world of computing, physical distance between parts of a computer system generally corresponds with the speed (latency-wise) of their communication,

Bandwidth Assessment:
I recall an article IGN released short after or during E3 2005 comparing Playstation 3 and Xbox360. Microsoft analyzed their total system bandwidth in the Xbox360 and came up with some outrageous numbers compared to the Playstation 3. One of the big reasons for this total number being higher is the 256GB/s bandwidth between the daughter die and parent die in the Xenos(graphics chip). I will explain the use of the eDRAM memory later, but it is important to know that the logic performed between those two components with 256GB/s bandwidth hardly constitutes a system component where considering game processing takes place. Additionally, Microsoft added up bandwidths that weren’t relevant to major component destinations such as “to CPU” or “to GPU.” Context like that matters a lot, because bandwidth between any two elements is only as fast as the slowest memory bus in-between. The only bandwidth figures that make sense to add together are those on separate buses to the end destination.

The biggest ugly (and this really is a big one) in the Xbox360 diagram should be the location of the CPU relative to the main system memory. It has to be accessed through the GPU’s memory controller. The Xbox360 GPU’s memory has 22.4GB/s bandwidth to the system’s unified memory, and this bandwidth is split between the GPU’s needs and the CPU’s. A simple investigation would show that if the Xenon(Xbox360 CPU) was using its full 21.6GB/s bandwidth to system memory, there would be 800MB/s left for the GPU. If the GPU was using it’s full bandwidth to this memory, none would be left for anything else. Additionally, the southbridge(I/O devices) is connected through the GPU also, and all of these devices are actually destined to go to the CPU unless sound for the Xbox360 is done on the Xenos. The impact of this is considerably less since I/O devices probably won’t exceed more than a few hundred MB/s during a game, and isn’t shared by GPUs 22.4GB/s access to main memory. This bandwidth is still going through the same bus that the CPU uses to access RAM though.

Looking at the diagram of the Playstation 3, you can see that the RSX has a dedicated 22.4 GB/s to its video memory, and the Cell has a dedicated 25.6GB/s to its main memory. Additionally, if you wanted to find the bandwidth the RSX could use from the Cell’s main memory, it go through the 35GB/s link between the Cell and itself, and then go through the Cell processor’s FlexIO controller, on the EIB, to the Cells memory controller which is the gatekeeper to RAM. The slowest link in the line is the bandwidth the XDR memory controller provides which is 25.6GB/s. If the RSX uses this extra bandwidth it is being shared with the Cell. In general though, the major components in the Playstation 3 have their own memory to work with which provides maximum bandwidth.

In terms of peak performance, if both the GPU and CPU for both consoles were pushing the maximum bandwidths from their respective memory banks, the total for Xbox360 would be 22.4GB/s, and the total for the Playstation 3 would be 48GB/s. I believe this to be the most important bandwidth measure as both of these elements are the major programmable elements of a gaming machine. They will be processing game data or graphics data independently, and need fast access and high bandwidth to what they are working on.

While the Xbox360 shared bandwidth is a big downside on the grand scheme of things considering potential, Microsoft probably allowed this due to the nature of a game loops often not involving both the CPU and GPU needing high bandwidth simultaneously. Overall, during a game loop, Xbox360 will probably use its 22.4GB/s bandwidth almost constantly due to the CPU using it heavily for a part of the game loop, and the GPU using extreme bandwidth during another part of the game loop. While a Playstation 3 game, if it uses a typical game loop design, would show half of the frame time, the CPU is using high bandwidth to its memory, the other half being mostly unused; and the same thing for the GPU’s use of video RAM. That isn’t a disadvantage of the Playstation 3’s part, but it is a lack of using its full potential. A modified game loop that kept both rendering and CPU processing high would fare far better on the Playstation 3’s bandwidth and design than the Xbox360.

In the worst case scenario for the Playstation 3, if the GPU literally only used bandwidth for half of the game loop, overtime, you could consider it’s bandwidth to be half of its peak. Same thing applied to the Cell and XDR RAM would yield 12.8GB/s bandwidth if it only used XDR half of the time. Although Playstaiton 3 not to be outdone - if the situation of a game loop is like this, the RSX might as well take the XDR RAM bandwidth while the CPU is idling and increase its total bandwidth to 48GB/s.

Xbox360 “Xenon” compared to Playstation 3’s “Cell” – the CPUs:
Inter-core communication speed:
Another mystery with the Xbox360 (at least in my view) exists with the inter-core communication on the Xenos CPU between its cores. IBM clearly documents the Cell’s inter-core communication mechanism physically and how it is implemented in hardware and software. This bandwidth needs to be extremely high if separate cores need to communicate and share data effectively. The EIB on the Cell is documented at a peak performance of 204GB/s with an observed rate at 197GB/s. The major factor that affects this rate is the direction, source, and destination of data flow between the SPE and PPEs on the Cell. I tried to find out the equivalent piece of hardware inside the Xenon CPU and haven’t found a direct answer.

Looking at the second architectural diagram of the Xenon, it seems that the fastest method the cores can use to talk to each other is through the L2 cache. Granted, the Xenon only has 3 cores, game modules are usually highly dependent and will need to talk to each other frequently. I might be a jumping the gun a bit, but given the L2 cache and FSB are running at half of the core speed, as opposed to the Playstation 3’s EIB which runs at the same clock speed as the cores, I’m pretty positive using L2 cache to communicate is not going to be very fast. It seems that independent threads are really what Microsoft was aiming for with the Xbox360 CPU design, and games are not optimally implemented if they have massive streaming transfers to hand off to other cores. What would suggest that the Xbox360 cores can communicate quickly and with high bandwidth, would be evidence that the reading and writing to the L2 cache are in larger segments than the writes to the EIB, compensating for the lower clock speed. Additionally, just writing to memory isn’t enough as the receiver needs some sort of notification that it has new data unless it is a permanent buffer. If anyone wants to do research on the topic, please add it to the discussion and include links to your sources.

Enhanced VMX-128 instruction set:
This is one of the features Microsoft boasts to claim they have a better gaming machine than Sony. They focus on the fact that their enhancements support a single cycle dot product instruction, and the larger register file. The problem with this boast over the Playstation 3 is that it compares it to the PPE’s VMX-128 unit which comparably only has 1 set of 32 128-bit registers and presumably less instructions. If the code requires 128 128-bit registers, or more complex instructions, then the code is most definitely vector processing heavy and should be run on an SPE which sports the exact same register file size, and includes a superset of the VMX instructions in terms of functionality(it is not a superset in terms of being binary compatible).

While each core in the Xbox360 also has two VMX-128 register sets, this is done to support the dual threaded nature of the cores better. It doesn’t actually have two vector execution units. Each core only has one VMX-128 execution unit meaning that even though there are two sets of registers per core, two threads that are using vector code have to share this single execution unit.

Comparably, the Cell’s PPE has the limited 32 128-bit register file with a single VMX vector unit on the PPE. This is what Microsoft usually singles out when they compare Playstation 3 to the Xbox360’s CPU. They forget(purposefully) that the Cell has 7 SPEs running at 3.2 GHZ, which is far greater SIMD performance than their 3 enhanced VMX-128 execution units. For vector based computations, the Playstation 3 undeniably outdoes the Xbox360 by an order of magnitude.

The dot product instruction claim is matched at least on the SPEs on the Playstation 3 though a simple multiply-add instruction. For those of you that aren’t mathematically inclined, a dot product is basically a measure of how parallel or perpendicular two lines are. The calculation of a dot product is basically multiplying each corresponding dimension value together, and then taking those products and adding them all together. Take two vectors <2, 3, 4> and <6, 7, 8>. The dot product would be: 2*6 + 3*7 + 4*8 = 65. If you read the earlier section in this post covering the SPES and SIMD architectures, you should remember that at the very least, an SPE can do all of the multiplying in one cycle, and all that needs to be done is a follow up add between the elements in the result vector. I do know that the SPEs have a few multiply-add instructions, but the bit of haziness is if the multiply can be an intra-vector(between two separate vectors) operation, while the add instruction is an inter-vector(between elements in the same vector) instruction from the result of the multiply. Sony claims that the dot product can be done in one cycle on an SPE, and it is very reasonable that this is the case as there are vector permute/shuffles/shift instructions in the SPE instruction set. There just isn’t a labeled dot product instruction in the SPE instruction set – but an intelligent programmer should find what he needs.

I found the multiply-add instruction in the Cell BE Handbook. It takes 4 vectors, one is definitely the result vector and two are operands, but the third parameter named ‘rc’, which I think represents a control register that dictates how to perform inter and intra vector operations. That means the multiply-add instruction has to operate on only two vectors, and the control vector is able to dictate an add between the result components of the multiply.

Symmetrical Cores?:
Symmetrical cores means identical cores. The appeal to this setup is entirely for developers. It represents no actual horsepower advantage over asymmetric cores since code running on any of the cores, will run exactly the same as it would run if it were on another core. Relocating code to different cores has absolutely no performance gain or loss unless it means something with respect to how the 3 cores talk to each other. It should be noted though, that thread relocation does matter between the cores, as a thread might not co-exist well with another thread that is trying to use the same hardware that isn’t duplicated on the core. In that case, the thread would be better located on a core that has that execution resource free or less used. The only case of this I can think of is the VMX-128 execution unit. I think most other hardware is duplicated on the cores in the 360 to allow for two threads to co-exist with almost no problem.

The Cell chip has asymmetrical cores, which means they are not all identical. That being said, the SPEs are all symmetrical with each other and the code that runs on an SPE could be relocated to any other SPE in the Cell. While the execution speed local to the SPEs are the same, there are performance issues related to the bandwidth the SPE is using and who it’s talking to on the EIB. Developers should look at where their SPE code is executing to ensure optimal bandwidth is being observed on the EIB, but once they find an optimal location to execute the code on, they can just put it there without rewriting anything. If a task was running on the PPE or PPE’s VMX unit, then it would have to be recompiled with C, and probably rewritten if hardware specific instructions are in the code(C or ASM) before it moves to an SPE, and the same applies in reverse. Good design and architecture should immediately let developers know what should run on the PPE and what should run on the SPEs, eliminating the chance of rewriting code if they see something better fit to run on an SPE later in development.

Is general purpose needed?:
Another one of Microsoft’s claims for the Xbox360’s superiority in gaming is the general purpose processing advantage since they have 3 general purpose cores instead of 1.

To say “most of the code is general purpose” probably refers to code size, not execution time. First, it should be clarified that “general purpose code” is only a label for the garden variety of instructions that may be given to hardware. On the hardware end, this code fits into various classifications such as arithmetic, load/store, SIMD, floating point, and possibly more. General purpose applications are programs made up of general purpose code on the scale that one function might be arithmetically heavy, and another might be memory bound. Good examples of this are MS Word, a web browser, or an entire operating system. With MS Word there is a lot of string processing which involves some arithmetic, comparison, a lot of branching, and memory operations. When you click import or export and save to various file formats, it is an I/O heavy operation. Applications like these tend to not execute the same code over an over, and have many different functions that can occur on relatively a small set of data depending on what the user does. These functions can vary from being very I/O device bound (saving to disk), to string processing intensive (spelling/grammar check), to floating point intensive(embedded Flash media game or resizing an image). Ultimately, there is a large amount of code written to handle the small set of data and most of it never gets executed.

Games are not general purpose programs. Any basic game programming book will introduce you to the concept of a game loop. This loop contains all of the functionality a game performs each frame. This loop handles all of the events that can occur in the game. An important principle in a game loop is to avoid branches when unnecessary as it slows down execution and makes the code on screen extremely and unnecessarily long. A good example of this is the Cohen-Sutherland line clipping algorithm. Instead of writing lengthy and complicated branches to check the 9 regions a point lies in, the code performs 4 simpler checks, and computes a region code which can be easily be used.

This automatic and repetitive processing has to occur for many game objects which represents a massive amount of data, with a relatively small code size. This is opposite of the general purpose paradigm, which typically has a small set of data (word document or html) and performs many various functions on it representing a large code size. Games processing has a large data size, but much smaller code size. Game objects also tend to be very parallel in nature as game objects are typically independent until they interact (collision) – which means they can be processed well on SIMD architectures if they are well thought out..

The whole integer advantage claim for the Xbox360 CPU is pretty stupid considering the SIMD architectures can operate on 4 32-bit integers at the same time, and integer processing abilities of games are not the bottleneck of 3D games processing.

What this general purpose power does grant Xbox360 owners over Playstation 3 is the ability to run general purpose applications faster. If the Xbox360 had a web browser(official or not), the design for such an application would work better on a general purpose CPU(s). That being said, it’s too bad Xbox360 doesn’t come with one, and web browsers don’t put the highest demand on general purpose processors to begin with. Most general purpose applications remain idle until the user gives actually input. The application will then process the task and complete before sitting idle again.

AI routines that navigate through large game trees are probably another area where general purpose processing power might be better utilized since this code tends to be more branch laden and varying depending on the task the AI is actually trying to accomplish. The plus side for the Playstation 3 is generating of these game trees, which is also time consuming. Generating a game tree is a more computational oriented task, and is likely to be executed faster by SIMD architectures. I am largely speaking speculatively under my Computer Science knowledge in this area. Anyone who knows more or has done more research on AI algorithms is welcome to add to discussion in this area.

The only case I can really see the general purpose computing power of the Xbox360 cores manifesting itself as a true advantage over the Playstation 3, is if Windows or similar OS was put on an Xbox360, having multiple applications running simultaneously along with some background services. Again, it is funny that Playstation 3 is more likely to have a general purpose operating system running on it than Xbox360 even though it would perform worse doing such a task.

XDR vs GDDR3 – System Memory Latency:
XDR stands for eXtreme Data Rate while GDDR3 stands for Graphics Double Data Rate version 3. XDR RAM is a new next generation RAM technology from those old folks at Rambus, who brought out that extremely high bandwidth RDRAM back during the onset of Pentium 4 processors. DDR was released soon after and offered comparable ...

[THELANDSOFSAND]

Playing A PS3 Like 'Driving A Honda'

[jedicurt]

so you are saying that it lasts long past it's warranty, is a smooth ride, with few problems, and is one of the key components to the failure of the US market in this industry???? nice to know that LandOfSand is a huge PS3 fan

[THELANDSOFSAND]

no i means it sucks, you lame honda driver

hahaha

[Say's you]

To say that Cha! yeah right its more like Microsoft paying the game developers to say that to there system like the original Xbox and now Xbox 360 saying positive words to the Xbox 360 when really Xbox 360 mostly use's Epics Unreal Engine 3 or Havoks graphics to make such great gameplay and graphics like Gears of War and Chromehounds Mass Effect and even BioShock Halo 3

unlike Sony they are saying the truth atleast they use thier own Graphics that Nvidia made for them well like Microsoft they alway's use more of Epics Unreal Engine or Havoks Graphics to make that happen cause they are ashamed of thier graphics card that ATI made for them I don't blame them it sucks thats

why there fooling Xbox 360 fans to think thats the actual power coming out of the Xbox 360 when really it isn't lol what a shame and pityful to do that to there own fans and FYI if the Xbox 360 is far superior to the Playstation 3 why are they keep using Epics Unreal Engine 3 and Hovaks graphics to make the game and gameplay?.