Next-gen console operating systems - resources reserved?

[Titanio]

This isn't a new topic, but I've just been looking over some of the things announced for PS3 at E3, and increasingly I'm wondering what kind of resources the OS will require. For example, Sony said at E3 that PS3 could be used for:

Digital Audio
Digital Video
Digital Photographs
Internet Browsing
Video Communication

and all simultaneously with gameplay. Also, in talking about the dual screen output, they talked about multiple applications across two screens, and controlling different channels of entertainment on different screens (which suggests things like one person browsing photos or watching a video on one screen, another playing a game on the other). They also talked about PS3 being "always on" and "always connected" to allow, for example, remote access over the internet from a PSP and the like. This suggests your PSP could "call home" and require attention from your PS3 at any time, including when someone else is playing a game.

Needless to say, X360 is incorporating a good deal of non-gaming functionality too, functionality which it can be called up at anytime too (audio, movies, photos etc.).

My question is - what kind of resources will these things require, and will Sony and MS reserve resources strictly to provide such services on demand, at any time?

Before E3, there was a VERY strong rumour that Sony was going to reserve a SPU for OS related functionality. This seemed to disappear after E3, however. Or has it? Is this still going to happen? It would seem relatively easy to slice off a SPU for the OS if needs be, but I would have thought we might have heard more about that if it were the case.

Or will it be simply another thread in the pot? On X360, this seems the most likely scenario (?)

 

[[maven]]

I'd say that for the 360, there'll simply a low-priority thread (at OS level, not a hardware thread!) that is scheduled automatically (for soundtracks, live, the "guide"). This shouldn't take much processor time away from the game (~5%-10% of a single hardware thread IME) plus a bit of ram (32mb max).
For PS3, much less is known; Sony has been known to post (at best) dubious claims / information; AFAIK noone knows whether the 8th SPU is disabled for yields or for OS functions, but OS tasks would be a lot better suited to the PPE than an SPE (more logic, less number crunching).

As an aside: Here's a Python script to compute Cell yields based on 7 / 8 intact SPEs

 

[Shifty Geezer]

Everyone knows the 8th SPE is disabled for yields! That's what Sony have said. Why some people choose to ignore them on this and imagine 'disabled for yields' means 'included and working but reserved for OS and background tasks' is quite beyond me!

 

[wco81]

Interesting topic. Is there really a demand for these other services to be using up precious memory?

I admit, the XBL feature of swapping game discs without rebooting sounds cool (well for consoles, since it's been that way for PCs all the time).

This is something Sony could use, especially if their game load times remain long, although there's no great clamor for it since both Playstations have been worse than the competition in game load times.

 

[Guden Oden]

Why some people choose to ignore them on this and imagine 'disabled for yields' means 'included and working but reserved for OS and background tasks' is quite beyond me!

It's called "wishful fanb0ythinking"! IMO, we should just consider the 8th (which might well be the 1st, 3rd, whatever) SPU dead and buried until the day PS3 is actually launched and we really know for sure. And even then it will probably still be dead.

 

[Shifty Geezer]

Even if it's alive (and if it was, an 8 SPE Cell surely it'd be reserved for higher-profile hardware like workstations?) it won't be used. There will be 7 active SPE's and 1 dead/inactive SPE, just as Ken Kutaragi has said.

Unless there's a sudden improvement in yields and they go with 8 SPE's, but assuming no changes...

 

[pipo]

Interesting topic. Is there really a demand for these other services to be using up precious memory?

It takes a lot of requirements out of the hands of devco's...

On top of that, a consistant interface is where it's at.

 

[Phil]

I don't think Titanio was refering to yields or anything the like. Regardless if there are 6, 7 or 8 SPE's active due to yields in the final PS3, the topic is about OS and services that require processing as well, which may mean that an additional SPE could be locked to run these services.

So, if CELL in PS3 launches with 7 active SPE's - could it mean that developers will only be able to use and access 6 of them, if one is reserved for "back-end services"?

 

[Pugger]

When the first rumours sufaced about the one SPE being deactivated it was also said that one of the SPE would be used for system resources. I don't know if this true or not.

 

[Shifty Geezer]

To date talk has always been of having 7 SPE's to run game code on. My guess would be that while playing a game, other services are deactiviated. You won't be web-browsing or watching an HD movie on one HDMI output while playing a game on the second. I would imagine that the machine operates without multitasking outside of the Linux HDD OS, just like the PSP either shows movies, pictures, plays music or games. You do one task at a time chosen from the boot-up options. To multitask like a PC would need the HDD kit and wouldn't allow gaming if not least for security/piracy issues.

The online aspect would still be there for games that employ online but I doubt that'll have much overhead at all. Taking a feature like Live!'s capacity to have a message or invitation pop up in game would only need an occasional poll of a messenger service, once every few seconds at worst. For other aspects like...

Needless to say, X360 is incorporating a good deal of non-gaming functionality too, functionality which it can be called up at anytime too (audio, movies, photos etc.).

I don't know that XB360 would allow you to watch movies the same time you play a game . If you want to switch out of the middle of a game to do something else like view someone's pictures there would need to be allowances for the resources that'd take up. Personally I wouldn't bother including those features though. I don't think the usefulness would warrant the drop in resources available to developers. How many people are going to want to stop slap bang in the middle of a game to watch a film say and not be content to save their progress and switch the console into video mode?

one's recent translation shows some 5% of cores 1 and 2 are being used for OS work. It's not a great deal but surely those OS operations are only going to be used a tiny fraction of the time the console is on and playing games?

 

[Mefisutoferesu]

I think of it like Sony has done the footwork to allow these options in an OS level manner, but it's up tot he developers to choose to implement them. So say some FPS dev decides to have realtime video chat for multiplayer with the 2nd screen. Rather than havig to worry about coding and designing this feature Sony's already provided the functionality in the OS, so the devs just have to call that into play and done. Yes, pitifully over simplified, but just to get the idea.

 

[DeanoC]

To date talk has always been of having 7 SPE's to run game code on.

No there hasn't, except for the some physical chip information there has been no public information on how those physical resources are being allocated and what will be available to games code.

 

[Ragemare]

Well in all the technicle papers I have read about Cell (not PS3 specifically) the PPC is reserved just for use by the OS Kernel... well either that or it's only the kernel which can explicitly specify a task to be done on the PPC. Doesn't make much sense to me.

 

[Shifty Geezer]

No there hasn't, except for the some physical chip information there has been no public information on how those physical resources are being allocated and what will be available to games code.

Well yes, but rather I was saying there's never to my knowledge been anything official saying 'there's 7 active SPE's, one of which will be dedicated to OS functions.' So as far as we know all 7 SPE's are available for game processing, but of course some OS functionality might cut into that maximum. In the same way we've just learnt from one's translation that XeCPU has 2 cores that manage OS functions on a part-time basis (5% of each core suggested) it could well be a percentage of PPE or an SPE is used on OS, which of course you're probably privileged to know. Surely a WHOLE SPE would be a lot of float power to waste on monitoring the internet for eMails though . And likewise reserving it for playing movies off an HDD for the second HDMI out would be a terrible waste considering how few users will have a second TV connected.

 

[Pugger]

Shifty, The rumour of the deactivated SPE was doing the rounds way before it was officially announced. I think I still have the mail from the source somewhere and I'm sure in the same mail it said that one of the SPEs was reserved for OS and other system requirements. Now the SPE turned out to be true, as for the OS stuff I don;t know I don't even know if an SPE will be any good at running it. All I know it was in the mail from initial source.

 

[V3]

Sony hasn't really say anything on this but for X360 isn't suppose to be able to switch in and out of game to dashboard, without quiting the game ? So in a way this is like the first multi tasking on console even if it is limited. PSP sort of did the same and its reported it took quite a chunk of memory (8MB?) for OS. Anyone know how much memory the OS occupies in X360 ?

 

[max-pain]

Anyone know how much memory the OS occupies in X360 ?

32 MB

http://www.xbox-scene.com/xbox1data/sep/EEEFuElkZEHGBSxpAf.php

 

[Titanio]

Well in all the technicle papers I have read about Cell (not PS3 specifically) the PPC is reserved just for use by the OS Kernel.

I haven't read everything, but I don't think this is true? Well the devs who were running their games thusfar on the PPE only would be pulling off some sort of miracle if it were true

And yes, in my original post, I was talking about the possibility of one of the 7 SPUs being reserved, leaving 6 for game code. I think that'd be acceptable.

 

[Fafalada]

I think that'd be acceptable.

In the end it doesn't mean a thing if it's acceptable or not since it's not like Sony will ask anyone about this.

That said, this report claims about 3.6% of CPU reserved on 360.
One reserved SPE would be 12.5% - more or less.
Let's not even think about what it would mean if Sony also reserved 4x more memory then MS...

But hey, if they reserve full SPEs, you should get bulletproof DRM in your PS3, so rejoice

 

[Titanio]

In the end it doesn't mean a thing if it's acceptable or not since it's not like Sony will ask anyone about this.

Hehe, true.

That said, this report claims about 3.6% of CPU reserved on 360.
One reserved SPE would be 12.5% - more or less.

Let's not even think about what it would mean if Sony also reserved 4x more memory then MS...

You really think they'd reserve 128MB of memory? That'd be surprising to say the least!

Re. SPEs, given the granularity of the architecture, the multiplicity of "cores", I think a SPE could be relatively easily reserved by Sony. It would be one less SPE, but there'd still be 6 there and the PPE. The impact wouldn't be HUGE for games, and although I'm sure it'd benefit Sony as much or more than the user (as you say, for things like DRM etc), the non-games or "complimentary" functionality or built-in OS services may offset any "pain" even just a little Games could also perhaps take advantage of some of that service directly, so it wouldn't necessarily be a total loss from that perspective.

I do think there will be an overhead though, a reasonable one at that. The things they spoke about at E3, as mentioned in the first post, and the way they talked about them as being "built-in" to the OS and even available during gameplay etc. seems to make that inevitable.