[Technical discussion] How limited would a PS3 emulator be by the PS4 hardware?

[Max|Payne]

Before I start, please, hold your drive-bys and witty replies, because this is not about whether or not Sony will do it or how many remasters they want to shove down our throats, but rather if they were to do it, how capable would that emulator be considering the limitations of the PS4 hardware. Understood? Good.

It's impressive how far along RPCS3 has gotten already. A good amount of games are already playable with minor to no noticeable issues. With a good enough computer you can even force them to render in 4K with better framerate. Reverse engineering alone has gotten the emulator this far, so imagine if they had access to the entire technical documentation and know-how that Sony has on the PS3.

Which brings me to point of this thread: realistically, how much could Sony achieve with a PS3 emulator on the PS4?

I'm talking straight emulation, no compatibility patches or anything. Plop the disc or download the digital version you bought on your PS3 and it just runs it right out of the box.

Is the console powerful enough to, at least, emulate at native settings with no other improvements? Could you force better resolutions without compromising performance? Could badly performing games find enough power to stabilize them?

I realize this will be mostly speculation and educated guesses, but I love talking about this stuff, even if my level of knowledge on this is pedestrian at best.

 

[Eolz]

Really limited due to the Cell's architecture and the PS4's CPU. The rest isn't that much of an issue.
edit: And to be fair to MS, they have an absolutely fantastic software experience and engineering team that I doubt that Sony have.

 

[Lowrys]

I have no technical knowledge but my understanding is that the cell processor, which is unique, would be an absolute bitch to emulate easily, if at all.

I'm sure someone more knowledgeable than me will give you a better answer, though.

 

[chrisypoo]

The Jaguar cpu just isn't capable of emulating the cell architecture at a serviceable quality. Not even the Pro's slightly overclocked CPU would be enough; it takes an i7 for rcps3 to be at playable quality last I heard, and the Jaguar isn't even in that ball park, no matter how much it's overclocked.

 

[DieH@rd]

As for doing it on PS4... I think it cannot be done.

SPUs are a serious business, a lot of horswpower would be needed for their emulation [even though Sony has access to IBM who have helped MS to create their Power CPU emulation].

; it takes an i7 for rcps3 to be at playable quality last I heard

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You should not compare what Sony could do with crowdfunded attempts of few external developers. Sony would have direct access to IBM, who would provide them great help in X86 emulation, and everything would be more optimized and faster.

 

[Max|Payne]

Could Sony use the GPUs compute features to run the stuff processed by the Cell SPUs?

 

[alr1ght]

Please don't compare a native emulator programmed by Sony to a group of hobbyists. Sony could probably get one up and running.

 

[Deleted member 442]

This is slightly OT but wasn't the PS4 release of USF4 some weird cobbled together port based on the PS3 version that emulated certain system calls? Hence why it had loads of weird bugs at launch? That may very well have just been speculation at the time.

Other Ocean developed that version for Capcom and they are normally known for doing emulated versions for old games like the Mortal Kombat Arcade Collection.

I think the point still stands above that the PS4 can not feasibly emulate a PS3, it's possible that they achieved some compromise between emulating certain pieces of the PS3 hardware and porting other elements of the game to run on PS4.

Likewise it probably wouldn't be worth the investment in time and money to get a fully fledged PS3 emulator to work on the PS4, that ship has sailed. Cross Gen games and re-releases covered the gap for the most part.

 

[ApeEscaper]

You need a more beefier machine to emulate PS3 hardware/software than Xbox 360 for more brute force

There is a PS3 emulator on PC and not Xbox 360 because of demand. Not many devs care to make emulator for Xbox 360 on PC as much as for PS3

You should not compare what Sony could do with crowdfunded attempts of few external developers. Sony would have direct access to IBM, who would provide them great help in X86 emulation, and everything would be more optimized and faster.

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The crowdfunded people have a bunch of access to internal info for the PS3 emulation so it's not far off

 

[Soluzar]

Ask yourself how much more powerful than a PS4 is the computer on which you run the emulator. Now ask yourself how good is that experience.

 

[Deleted member 2474]

Please don't compare a native emulator programmed by Sony to a group of hobbyists. Sony could probably get one up and running.

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Yup. Look at Xenia versus the One's extremely capable 360 emulation. Night and day. Just because RPCS3 requires beefy specs isn't indicative of what a professional team with deep understanding and documentation of the PS3 could do.

 

[Tagg]

Virtually impossible. You would need to distribute the load on the PS3 cell's main processor to instead be spread across the PS4's multiple Jaguar cores, something that would be impossible to reliably schedule without altering the code on a game-by-game basis.

 

[HanzSnubSnub]

Given the complexity of cell, I doubt the results would be anything stellar. It would be a huge accomplishment getting it to even run on Jaguar. Considering the SPU code would have to be entirely simulated, games like Uncharted that heavily rely on this would crawl.

But the more realistic fact is that PlayStation's software team is tiny compared to MS. Rumour is that years of work is going into changing PSN names, something small in comparison to emulation. I really doubt they have the capacity to pull anything like a full blown PS3 emulator off.

 

[Code Artisan]

Is the ps4 jaguar more powerful than the ibm cell?

 

[Patitoloco]

The problem, as others specified, is the super weird Cell architecture. Of course, it's not impossible to emulate (see RPCS3), but at the moment pretty much every game would need to have specific profiles, and that needs of resources I doubt Sony has, but without any doubt Microsoft has.

Still, just to compare it to the Xbox One's backwards compatibility, the 360 emulation is done by a generic emulator that they have integrated at an OS level, with a few tweaks to prevent unexpected bugs. But, if you check out the Xbox OG emulation, even Microsoft is having a lot of problems, and they have to pretty much tailor every instance of the emulator to each game.

 

[RogerL]

Could Sony use the GPUs compute features to run the stuff processed by the Cell SPUs?

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I think this is the only possible way on PS4, in addition this is also how I think games are expected to be implemented.
What was SPU jobs should now be GPGPU jobs.

This might result in a emulator for games that do not try to use every resource available on the PS3...
To get a cycle exact emulation required for some games...

Compare with
https://rpcs3.net/compatibility

 

[Max|Payne]

Just to clear things up for me, were the SPUs the weird part of the Cell or was the main processor unorthodox as well?

 

[senj]

Is the ps4 jaguar more powerful than the ibm cell?

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"More powerful" isn't a one-dimensional thing. They have different strengths and weaknesses. The jaguar's performance in integer calculations on any main thread should be higher. The Cell can juggle many more floating point ops at the same time with much higher peak data bandwidth if you can organize your calculations correctly.

 

[senj]

Just to clear things up for me, were the SPUs the weird part of the Cell or was the main processor unorthodox as well?

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The main processor, the PPU, isn't much different than any single core of the 3 cores in the 360. In fact the cores in the 360 were just lightly modified PPUs.

The SPUs are wild little vector processors. Very nonstandard. Almost like Intel's Larrabee idea, kind of. The relation between the two things, with the PPU acting mostly as a overseer for workload distribution to the SPUs, is also different than what you'd run into in other architectures at the time (although nowadays it's not unlike GPGPU programming paradigm).

 

[Inuhanyou]

Its not possible to run PS3 emulators full speed on jaguar because of the SPU's and other hardware intricacies., hell i have doubts it would even run.

Having access to documentation alone is not enough to bridge a CPU gap of that magnitude which would be required.

 

[Deleted member 5956]

Yup. Look at Xenia versus the One's extremely capable 360 emulation. Night and day. Just because RPCS3 requires beefy specs isn't indicative of what a professional team with deep understanding and documentation of the PS3 could do.

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The XBox One is far too weak to emulate the 360's CPU so they recompile the games executable into x86 code, this is then run natively on the Xbox One. So actually the Xbox One is emulating very little of the 360's hardware and even that is high level, requiring per game workarounds and hacks to run as intended.

Xenia's problem is that no one is interested in working on 360 emulation. Put the same number of people to work on it as have developed Dolphin and you would have a very capable emulator by now.

 

[Deleted member 22585]

The Jaguar cpu just isn't capable of emulating the cell architecture at a serviceable quality. Not even the Pro's slightly overclocked CPU would be enough; it takes an i7 for rcps3 to be at playable quality last I heard, and the Jaguar isn't even in that ball park, no matter how much it's overclocked.

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I'm not very well versed regarding that stuff, so don't be to harsh. But there are straight up ports like TLOU or GOW3 that are handled very well, so it shouldn't be impossible to have a good emulator or is there something I don't get?

 

[Max|Payne]

I'm not very well versed regarding that stuff, so don't be to harsh. But there are straight up ports like TLOU or GOW3 that are handled very well, so it shouldn't be impossible to have a good emulator or is there something I don't get?

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Remasters/ports are adaptations of the game code into different hardware. It's not emulation.

 

[Deleted member 11517]

I'm not very well versed regarding that stuff, so don't be to harsh. But there are straight up ports like TLOU or GOW3 that are handled very well, so it shouldn't be impossible to have a good emulator or is there something I don't get?

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Read post above you, these games are most likely recompiled to run on PS4, and thus not really emulated.

 

[Inuhanyou]

I'm not very well versed regarding that stuff, so don't be to harsh. But there are straight up ports like TLOU or GOW3 that are handled very well, so it shouldn't be impossible to have a good emulator or is there something I don't get?

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Ports are not emulation. Ports are the game code itself recompiled and adapted and fully optimized to the hardware itself, which is incomparable. Emulators are usually brute force affairs that have no fine tuning applied, it is literally running the original game code on the pure brute force of the hardware components.

 

[foolishoptimist]

I remember reading that most 3Rd party games from early in that gen ran entirely on the PPU with no SPU use at all.

So I'd guess there are some games that would be easily emulated. I'd imagine ND games being hardest to emulate with decent performance, without sheer brute force of CPU power.

 

[senj]

I'm not very well versed regarding that stuff, so don't be to harsh. But there are straight up ports like TLOU or GOW3 that are handled very well, so it shouldn't be impossible to have a good emulator or is there something I don't get?

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Porting and recompiling software for a different platform is totally different than emulating the original hardware it ran on, and the performance of one vs the other are largely unrelated.

 

[EightBitNate]

The Jaguar cpu just isn't capable of emulating the cell architecture at a serviceable quality. Not even the Pro's slightly overclocked CPU would be enough; it takes an i7 for rcps3 to be at playable quality last I heard, and the Jaguar isn't even in that ball park, no matter how much it's overclocked.

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I imagine a Jaguar CPU couldn't run Xenia very well either.

 

[Inuhanyou]

The XBox One is far too weak to emulate the 360's CPU so they recompile the games executable into x86 code, this is then run natively on the Xbox One. So actually the Xbox One is emulating very little of the 360's hardware and even that is high level, requiring per game workarounds and hacks to run as intended.

Xenia's problem is that no one is interested in working on 360 emulation. Put the same number of people to work on it as have developed Dolphin and you would have a very capable emulator by now.

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This is why its wrong to compare what MS is doing for BC versus possible PS3 "emulation" on PS4. Its not even the same type of thing.

 

[Deleted member 5956]

Ports are not emulation. Ports are the game code itself recompiled and adapted and fully optimized to the hardware itself, which is incomparable.

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And Naughty Dog said that even porting TLOU was incredibly difficult...

"We expected it to be hell, and it was hell. Just getting an image onscreen, even an inferior one with the shadows broken, lighting broken and with it crashing every 30 seconds … that took a long time. These engineers are some of the best in the industry and they optimized the game so much for the PS3's SPUs specifically. It was optimized on a binary level, but after shifting those things over, you have to go back to the high level, make sure the systems are intact, and optimize it again."

 

[Inuhanyou]

And Naughty Dog said that even porting TLOU was incredibly difficult...

"We expected it to be hell, and it was hell. Just getting an image onscreen, even an inferior one with the shadows broken, lighting broken and with it crashing every 30 seconds … that took a long time. These engineers are some of the best in the industry and they optimized the game so much for the PS3's SPUs specifically. It was optimized on a binary level, but after shifting those things over, you have to go back to the high level, make sure the systems are intact, and optimize it again."

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Exactly.

Even MS's XB1 solution is hit and miss. We can see this in the Dark Souls 1 360 version running on XB1, versus what little we know of the remaster running natively and optimized for the same hardware. sub 720p with sub 30fps in a large amount of areas versus 1080p 60fps. What Bamco did to the Dark Souls 1 code to get it to run is very significant compare to the previous console versions and the PC version

 

[Kuosi]

It would be a nightmare to somehow spread the load to 7 cpu threads efficiently

 

[Dreamboum]

Please don't compare a native emulator programmed by Sony to a group of hobbyists. Sony could probably get one up and running.

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What can be native about two consoles that doesn't share the same architecture at all ?

 

[fiendcode]

Even if CELL is an SPU too far, how about emulating PS1/2 Classics and digital PSP/Vita games? There's a ton of backwards compatibility Sony could be doing.

 

[Green Yoshi]

Is Ryzen fast enough to emulate PS3 games? Then we could see PS3 games in the store of the next PlayStation.

At least PS4 can emulate the Emotion Engine that is also quite complicated due to two vector processors.

 

[Max|Payne]

Even if CELL is an SPU too far, how about emulating PS1/2 Classics and digital PSP/Vita games? There's a ton of backwards compatibility Sony could be doing.

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Sony already has a PS2 emulator that works on PS4. The PS2 classics releases on PS4 are emulated.

 

[Shifty1897]

It's impossible. The PS4 struggles to emulate even PS2 games, as I recently discovered with Rogue Galaxy.

 

[Deleted member 38397]

The XBox One is far too weak to emulate the 360's CPU so they recompile the games executable into x86 code, this is then run natively on the Xbox One. So actually the Xbox One is emulating very little of the 360's hardware and even that is high level, requiring per game workarounds and hacks to run as intended.

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That's incorrect. The game code for every single backward compatible title remains untouched. Even on X1X enhanced titles.

 

[Max|Payne]

That's incorrect. The game code for every single backward compatible title remains untouched. Even on X1X enhanced titles.

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Doesn't XB1 BC basically consist of running the 360's OS on a virtual machine?

 

[Zoph]

Probably not until PS5. I hope Sony are thinking of a way to get that PS3 backlog compatible with a stronger, future x86 architecture.

 

[fiendcode]

Sony already has a PS2 emulator that works on PS4. The PS2 classics releases on PS4 are emulated.

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Yes but I'm talking about the previous Classics (PS3) as backwards compatibility. If you want 1080p and trophies you can get the newer $20 versions.

 

[Deleted member 5956]

That's incorrect. The game code for every single backward compatible title remains untouched. Even on X1X enhanced titles.

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Bill Stillwell, Xbox Platform Lead-

"We take each game, we recompile it so that it runs, but basically we're running it still in a 360, and the team goes through the game with multiple passes."

 

[Deleted member 5956]

double post.

 

[Deleted member 38397]

Bill Stillwell, Xbox Platform Lead-

"We take each game, we recompile it so that it runs, but basically we're running it still in a 360, and the team goes through the game with multiple passes."

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Well you can't argue with Bill. But how do they recompile the PowerPC executable without having access to all the original source code?

Or does he mean that they recompile the virtual 360 emulator with the original game code wrapped inside? (And therefore the code remains unmodified?)

Basically, we have a VGPU - or an Xbox 360 GPU that we've recompiled into x86 - and we run the entire 360 OS stack," explains Bill Stillwell, Xbox Platform Lead. "We take each game, we recompile it so that it runs, but basically we're running it still in a 360, and the team goes through the game with multiple passes."

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I think he means they recompile the VGPU for every game, not the games themselves.

 

[Digital Savior]

If they're just porting instructions over, impossible.

If they take the time to work the code and recompile, plausible.

From information released, it seems like Microsoft uses the second approach. I feel like Sony could, but they probably feel like they don't need to; as they're still selling extremely well.

The last approach would be to include cell hardware in a ps4/5 box. Probably too expensive to do this.

 

[Deleted member 721]

I'm curious to PS5 to be honest, it's too late for 4

 

[gebler]

For Sony, the big problem with emulating the PS3 SPUs would not be their complexity, but the mismatch between the performance characteristics of the SPUs and anything available on the PS4. A single SPU is simply faster than any single core in the PS4 for tasks ideally suited for it, and PS3 games go to great lengths to structure its performance-critical code so that it's a good fit for the SPUs. To get a simplistic idea of the uphill battle, PS3 SPUs run at 3.2 Ghz while the PS4 Jaguar cores are running at 1.6 GHz and its GPU cores at 0.8 GHz (2.13 GHz and 0.911 GHz for the Pro). Granted, a Jaguar core could possibly get more done running at 1.6 GHz than an SPU at 3.2 GHz in general, but for code especially optimized for the SPU, not a chance. And that is even without taking emulation overhead into account, i.e. assuming some kind of impossibly perfect JIT recompiler.

Full-speed PS3 emulation on the PS4 could still be possible, if some effort is spent on each supported game, much like what Microsoft has been doing for the Xbox One and 360. But since the architectural differences are larger, it would probably mean a lot more work per game, e.g. outright replacement of the most problematic engine code with PS4-optimized code.

 

[Y2Kev]

I would be curious to hear Sony actually let an engineer address the question (even if it's Cerny) more than someone like Jim Ryan. I think it's not possible, or not worth their time, but I'd be curious if that were actually the case vs. just the conventional wisdom.

 

[Deleted member 5956]

I think he means they recompile the VGPU for every game, not the games themselves.

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But the VGPU is x86 and the original games code is built around hardware that isn't. So you HAVE to recompile it to also be x86 or it wont run. He pretty clearly states that both the are recompiled in the full quote you posted.

Basically, we have a VGPU - or an Xbox 360 GPU that we've recompiled into x86 - and we run the entire 360 OS stack," explains Bill Stillwell, Xbox Platform Lead. "We take each game, we recompile it so that it runs, but basically we're running it still in a 360, and the team goes through the game with multiple passes."

 

[Max|Payne]

So, realistically, Sony would have to fiddle with the game's code anyway in order to get PS3 emulation on PS4 going smoothly, right?