'Graphic North Bridge' PlayStation 4's Custom Chip?

[Shifty Geezer]

Other than the Sony announcement.

We also have the Edge's rumours predating the PS4 reveal that were right on the money in a number of areas (8Gbs RAM, touch controller) that described the architecture as an 8+18 APU called Liverpool, whcih fits exactly with what Sony announced.

But OnQ is completely hung up on these old rumours and is unwilling/unable to listen to reason, so there's not much point in trying to discuss it IMO. If every argument comes back to those rumours, without any explicit way to convince him they were wrong despite all the implicit evidence as such, this discussion is a dead end. All the technical arguments in the world will achieve nothing as the basis of his theory is undisprovable and ambiguous rumours and comments.

 

[onQ]

We also have the Edge's rumours predating the PS4 reveal that were right on the money in a number of areas (8Gbs RAM, touch controller) that described the architecture as an 8+18 APU called Liverpool, whcih fits exactly with what Sony announced.

But OnQ is completely hung up on these old rumours and is unwilling/unable to listen to reason, so there's not much point in trying to discuss it IMO. If every argument comes back to those rumours, without any explicit way to convince him they were wrong despite all the implicit evidence as such, this discussion is a dead end. All the technical arguments in the world will achieve nothing as the basis of his theory is undisprovable and ambiguous rumours and comments.

Do you mean this? http://www.edge-online.com/news/playstation-4-revealed/2/

Both platforms are driven by eight-core AMD CPUs clocked at 1.6GHz, with Microsoft opting for a D3D11.x GPU from an unknown source and Sony utilising a more capable solution in AMD’s ‘R10XX’ architecture, alongside the so-called ‘Liverpool’ system-on-chip.

The Edge article actually make it sound as if there is a CPU + GPU + SoC because they said alongside of the so-called ‘Liverpool’ system-on-chip.

 

[AlphaWolf]

We also have the Edge's rumours predating the PS4 reveal that were right on the money in a number of areas (8Gbs RAM, touch controller) that described the architecture as an 8+18 APU called Liverpool, whcih fits exactly with what Sony announced.

It doesn't align with the announced performance.

 

[Love_In_Rio]

Well, to be honest Sony seems to have still something in its sleeve that we do not know. Be it VR glasses, expandable console or what, we don´t know. There are tips here and there ( Yoshida saying they didn´t let journalists touch the DS4 because of a secret, the console not being shown because of a undisclosed characteristic, etc ), but, well, it also could be nothing in the end.

ERP?

 

[Exophase]

The Edge article actually make it sound as if there is a CPU + GPU + SoC because they said alongside of the so-called ‘Liverpool’ system-on-chip.

This is what happens when you get potentially valid information filtered by people who don't understand what it means.

Look back at rumors dating since early 2012 - the codename Liverpool has always referred to the APU. Not a part of the APU. Not a separate SoC. From your posts I'm not really sure you even know what SoC means, despite its name being pretty self describing (or do you not know what it stands for?) You can't have something that's both an SoC AND part of an APU. Since it's established that the APU doesn't integrate all the I/O functionality it's not a true SoC itself; the southbridge chip could qualify as an SoC but probably not in a useful sense (and certainly not how it's being used).

 

[DJ12]

Suprised this thread is still going. There is no secret sauce. The end.

Onq I find your sony love inspiring but theres an 18 cu gpu in the ps4s apu and an 8 core jaguar cpu. That is all. Its all ready the largest apu in existence what more do you realistically think they've done they are already in the unknown with what I've said.

 

[onQ]

This is what happens when you get potentially valid information filtered by people who don't understand what it means.

Look back at rumors dating since early 2012 - the codename Liverpool has always referred to the APU. Not a part of the APU. Not a separate SoC. From your posts I'm not really sure you even know what SoC means, despite its name being pretty self describing (or do you not know what it stands for?) You can't have something that's both an SoC AND part of an APU. Since it's established that the APU doesn't integrate all the I/O functionality it's not a true SoC itself; the southbridge chip could qualify as an SoC but probably not in a useful sense (and certainly not how it's being used).

I know what a SoC is & I know what a APU is & I was the person who 1st broke the news that the chip code name was Liverpool on Neogaf last year when everyone thought the story was fake.

I was just pointing out that from what Edge said in that article it made it sound like it was a GPU along with the SoC because they said alongside the SoC.

Suprised this thread is still going. There is no secret sauce. The end.

Onq I find your sony love inspiring but theres an 18 cu gpu in the ps4s apu and an 8 core jaguar cpu. That is all. Its all ready the largest apu in existence what more do you realistically think they've done they are already in the unknown with what I've said.

Not secret sauce I think it's all the same thing that's been talked about already.

 

[Tahir2]

If the Southbridge has an integrated ARM CPU for background tasks, will this need its own GPU as well? I would imagine to make it as efficient in energy consumption as possible that there would be some sort of GPU unit, with RAM.

Now if it does have a GPU inside that Southbridge, who built it? I have a feeling it isn't an AMD GPU, maybe it is Mali or something else cheap. Mali has proven to be quite efficient when idling in some of Anandtech's tests recently.

Or... as onQ is kind of pointing out, Sony went crazy and has integrated fully fledged Radeon Compute Units into the Southbridge as well.

Who knows? Sony can keep some information to itself for later.

All the above is complete speculation on my part..

 

[AlphaWolf]

If the Southbridge has an integrated ARM CPU for background tasks, will this need its own GPU as well? I would imagine to make it as efficient in energy consumption as possible that there would be some sort of GPU unit, with RAM.

Now if it does have a GPU inside that Southbridge, who built it? I have a feeling it isn't an AMD GPU, maybe it is Mali or something else cheap. Mali has proven to be quite efficient when idling in some of Anandtech's tests recently.

Or... as onQ is kind of pointing out, Sony went crazy and has integrated fully fledged Radeon Compute Units into the Southbridge as well.

Who knows? Sony can keep some information to itself for later.

All the above is complete speculation on my part..

They can keep stuff to themselves but they wouldn't put out a performance number if the actual number was 40% higher.

 

[Tahir2]

If there was a Compute GPU in the Southbridge (to be used alongside the APU GPGPU) it would go against the principles of HSA which tries to integrate the GPGPU functions as close to the CPU as possible. So, no I do not believe there is anything significant in the Southbridge to warrant all this attention... was just adding my two cents.

Some good documentation on HSA which is what will hopefully make a real difference to how developers use the TFlops of power available to them:

http://developer.amd.com/resources/...hat-is-heterogeneous-system-architecture-hsa/

The HSA team at AMD analyzed the performance of Haar Face Detect, a commonly used multi-stage video analysis algorithm used to identify faces in a video stream. The team compared a CPU/GPU implementation in OpenCL™ against an HSA implementation. The HSA version seamlessly shares data between CPU and GPU, without memory copies or cache flushes because it assigns each part of the workload to the most appropriate processor with minimal dispatch overhead. The net result was a 2.3x relative performance gain at a 2.4x reduced power level*. This level of performance is not possible using only multicore CPU, only GPU, or even combined CPU and GPU with today’s driver model. Just as important, it is done using simple extensions to C++, not a totally different programming model.

HW Configuration

4GB RAM; Windows 7 (64-bit); OpenCL™ 1.1
APU: AMD A10 4600M with Radeon™ HD Graphics
CPU: 4 cores @ 2.3 MHz (turbo 3.2 GHz)
GPU: AMD Radeon HD 7660G, 6 compute units, 685MHz

Should be cool stuff.

 

[Gipsel]

If the Southbridge has an integrated ARM CPU for background tasks, will this need its own GPU as well? I would imagine to make it as efficient in energy consumption as possible that there would be some sort of GPU unit, with RAM.

To make it as efficient and cheap as possible, one would omit any GPU because a game console in standby mode won't display anything. It powers a tiny ARM chip (A7 or even just an A5) and the ethernet port and/or WiFi to handle downloads (buffered on a few GBs of cheap flash memory so the harddrive doesn't need to spin all the time?). That's all. I would guess the goal is to get away with something in the low single digits of Watts (<=2) at the wall for that functionality. The power supply will likely provide a dedicated standby lead just as ATX does to increase the efficiency in that low load range (probably limited to ~10W capacity, just enough to power that background activity and a USB port for charging controllers when the console is off or whatever).

 

[3dilettante]

I'm curious if it needs to be an A5 or A7. There are smaller ARM cores used for storage and networking. If it's treated as a southbridge component, it's not going to need many of the additions to the architecture or have to present a familiar face to developers.

 

[patsu]

You talked about that idea before.

What other ARM cores are used to manage HDD and network modules in general and what are their performance level ?

AMD mentioned A5 in their TrustZone announcement, but again PS4 may or may not use TZ.

That ARM CPU may be active outside sleep mode, running some supporting functions.

EDIT:

To make it as efficient and cheap as possible, one would omit any GPU because a game console in standby mode won't display anything. It powers a tiny ARM chip (A7 or even just an A5) and the ethernet port and/or WiFi to handle downloads (buffered on a few GBs of cheap flash memory so the harddrive doesn't need to spin all the time?). That's all. I would guess the goal is to get away with something in the low single digits of Watts (<=2) at the wall for that functionality. The power supply will likely provide a dedicated standby lead just as ATX does to increase the efficiency in that low load range (probably limited to ~10W capacity, just enough to power that background activity and a USB port for charging controllers when the console is off or whatever).

When I have time, I'll talk about an interesting setup in my first job many years ago. It was a radar tracking system, one CPU ran BSD and modern APIs, the other CPU ran a proprietary embedded RTOS with a cooperative scheduler, perhaps not unlike SPURS; and they share the same memory. ^_^

 

[Gradthrawn]

It powers a tiny ARM chip (A7 or even just an A5) and the ethernet port and/or WiFi to handle downloads (buffered on a few GBs of cheap flash memory so the harddrive doesn't need to spin all the time?).

That's not going to cut if for full game downloads initiated by the PlayStation App (or auto predicted). In which case, I can't see additional flash storage (slow or not) being cost justified when you might as well just send it all to the HDD.

EDIT

Unless you mean buffering as in storing up a few gig of data first and then sending it to the drive as the flash fills. That way large sequential blocks of data are written instead of potentially smaller chunks. Not sure what kind of power saving that would really offer, though.

 

[ERP]

OK let me throw this out there on Sweetvars post
There is almost nothing in it that I can map back to useful information.

 

[patsu]

Yeah... not unless we receive new info about apps that cannot be adequately handled by the current setup (PSEye ?).

 

[3dilettante]

You talked about that idea before.

What other ARM cores are used to manage HDD and network modules in general and what are their performance level ?

AMD mentioned A5 in their TrustZone announcement, but again PS4 may or may not use TZ.

That ARM CPU may be active outside sleep mode, running some supporting functions.

It's at least claimed that Samsung's latest SSDs are using ARM9 cores, although OCZ latest is said to use a member of the Cortex family, but that's a broad category that includes chips below the A series.

The various architectures have variants that appear in a lot of niches, so it seems plausible enough.

edit:
One thing about counting on the southbridge processor to perform support functions is that the southbridge is not normally cache-coherent. It shouldn't be trying to help with system functions for the main system too much, outside of the usual copies and moves to spaces defined by the OS on the primary CPU.

 

[patsu]

Yap, it'd usually be async and there'd be copying involved if they want to use both at the same time (e.g., unpack and copy somewhere). You can allocate an area of shared memory for IPC if necessary.

I expect the GPU to do all the rendering though. It has a high priority VSHELL queue for OS/XMB use.

 

[Gipsel]

I doubt it's much of a difference if one uses a 0.53mm² A5 (on 40G, including caches) or a roughly same size and speed R5 (one could opt for the slightly smaller R4 of course). Significantly smaller are only the Cortex-M cores (<<0.1mm²), but they are also more limited. And as one needs a few pads anyway, I don't know if it makes a lot of sense to save maybe a cent or two there.

 

[3dilettante]

It's somewhat smaller cores and also an ISA revision that is several back from the A series.
Granted, I'm only assuming this is cheaper to license than going for an A5 or A7 core.