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      /  AckOne High-End Will Run PA Semi Multi-core
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Hans 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:01:50
#141 ]
Elite Member
Joined: 27-Dec-2003
Posts: 4927
From: New Zealand

@Jorge

Quote:

Jorge wrote:
@Hans

:

Well, for the Amiga, whatever shader language you'd choose, there's nothing available (or even possible) at this point.


True. The Friedens said that a MESA implementation would come once a new graphics system was in place. This should include GLSL. My point was that GLSL is a better choice than Cg.

Quote:

Can we agree, that we should start to walk before we begin to run ? Currently Amiga is crawling. Getting OS4 on a multicore - even without optimal performance - could prepare the next step (which probably won't be OS4 any more). We have a chicken and egg problem here. Seems the HW will come, an OS can be made available for it, everything else will take another 2+ years anyway. In that time, people can play OS4, some might even be able to make some money. How long do you want to wait to make another version of AmigaOS ? Add some more features and delay it another 2 years ?


I'd be perfectly happy if forbid/permit initially stalled both CPUs. It's a temporary step. They can improve things step by step.

Hans

Last edited by Hans on 06-May-2007 at 06:26 PM.
Last edited by Hans on 06-May-2007 at 06:03 PM.

_________________
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CodeSmith 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:05:56
#142 ]
Elite Member
Joined: 8-Mar-2003
Posts: 3045
From: USA

@debrun

Remember also that the initial market for these boards is going to be just a few hundred. That could well fit into the "samples" volume, since "full production" volume for chips usually means millions.

Right now I'm more worried about the licensing lawsuit though.


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adiaux 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:11:08
#143 ]
Super Member
Joined: 1-Jun-2006
Posts: 1249
From: Unknown

@Kronos

Don't bother, they *don't want* to understand...

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CodeSmith 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:15:00
#144 ]
Elite Member
Joined: 8-Mar-2003
Posts: 3045
From: USA

@takemehomegrandma

I guess that means that every time anything goes wrong with OS4, we can count on you two to come tell us it's because of SMP and Forbid?

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DrBombcrater 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:18:07
#145 ]
Super Member
Joined: 6-Feb-2004
Posts: 1382
From: UK

@CodeSmith

Quote:
You're falling into the familiar trap of comparing artificial benchmarks across cpu architectures. PPC and x86 instruction sets are so different that the only benchmarks that really count are wall-clock ones. I'd like to see comparisons of say the time it takes to do a ray trace, or to encode a certain piece of music into MP3. Then we can do meaningful comparisons.

SpecInt scores are all we have to go on right now for the PA Semi chip, which possibly isn't a good sign. Manufactuers of high performing chips usually scream as many benchmark results as possible, as loudly as possible.

But, yes, I agree. Results from more real-world tests would be much more informative.

Quote:
Wide range available? There are just a handful of NB chips than can talk Hypertransport, and in any case you're constrained by the 2000MT/s bandwidth so you can't just keep adding peripherals. The description of PCI express support is a bit confusing, but it sounds like you get what most x86 NBs give you: 1x16 and a few more lanes split between x8, x4, x2 and x1. Sure, you don't get 2x16 Crossfire support, but I think only one NB from NVidia supports that.

There's a ton of hypertransport system chips out there. I could name 20 of them just from memory. Bandwidth issue are not a problem with HT because you simply hang a second system controller chip from another HT link (Opterons have up to 3 HT links, for example). This is how NVidia's 'server/workstation' chipsets work, they're really just two desktop syscontroller chips working in tandem.

I must confess, I don't really understand how the 1682 handles PCIe. It seems to have 24 'serial lanes', some of which are used by on-board devices like the ethernet controllers, with the others being available for PCIe use. It's an interesting and potentially very flexible system, but I've seen references to an upper limit of 8 PCIe lanes which would be rather less than optimal.

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itix 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:23:27
#146 ]
Elite Member
Joined: 22-Dec-2004
Posts: 3398
From: Freedom world

@Hans

Quote:

Yes it would still run, and it would be slower than it should, because Forbid()/permit() will stall all cores.


And what about SysBase->ThisTask ?

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CodeSmith 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:27:32
#147 ]
Elite Member
Joined: 8-Mar-2003
Posts: 3045
From: USA

@DrBombcrater

Fair enough, but you have to admit that the vast majority of consumer boards use only one HT link. I'm not sure how well the 1682 would do in a server environment, too many questions are unanswered. I still think it would make a pretty slick workstation, the requirements are much lower there.


@Kronos, takemehomegrandma

Read DrBombcrater's post, this is how one argues his point. Facts and logical deduction, not innuendo and condescention.

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Hans 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:28:37
#148 ]
Elite Member
Joined: 27-Dec-2003
Posts: 4927
From: New Zealand

@itix

Quote:

itix wrote:
@Hans

Quote:

Yes it would still run, and it would be slower than it should, because Forbid()/permit() will stall all cores.


And what about SysBase->ThisTask ?


Were people ever supposed to read that directly?

Hans

_________________
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adiaux 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:34:08
#149 ]
Super Member
Joined: 1-Jun-2006
Posts: 1249
From: Unknown

@CodeSmith

There are two ways of obtaining things like real SMP and real memory protection

1) Kiss all bakwards compatibility (I'd like to call that *Amiga* compatibility) and Amiga applications goodbye, create a *new* OS based on modern concepts (why not throw in multi-user support as well when you are at it, and a POSIX layer, for easy porting of modern applications like browsers, office programs, etc), and call that OS "AmigaOS" instead of what we all know and recognize as Amiga today.

(But since it won't be Amiga anymore, other than by the name, why bother in the first place? Why not simply use one of the OS's that already have all these features, and have a huge stack of modern applications as well, instead of beginning to climb the first steps on a stairway at the height of Mount Everest?)

2) Sandbox the Amiga envireonment altogether in order to keep it as Amiga compatible as possible, and run all "modern" features outside of that box, and simply accept that whatever is *inside* the box won't ever benefit from those OS features.

(But wouldn't that be like ... MorphOS? (Quick now: spit-spit-spit, salt over the shoulder, ten Ave-Maria!))

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Moxee 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:35:30
#150 ]
Team Member
Joined: 20-Aug-2003
Posts: 6291
From: County Yakima, WA State, USA

@ssolie

Quote:

ssolie wrote:
@takemehomegrandma
Quote:
OK, let's try with some pedagogy for two-yearolds

AmigaOS is evolving beyond your little box analogy. The box is changing. The pieces are changing. Some people can't handle change and stay with the same box and pieces and are happy to play with them the way they are until they die. Enjoy your little box while the adults move on to bigger and better things.


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CodeSmith 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:37:48
#151 ]
Elite Member
Joined: 8-Mar-2003
Posts: 3045
From: USA

@itix

SysBase would probably have to be different for each CPU. That's not a huge deal because the first page frame has to be virtualized anyway (the null pointer detection code has to special-case address 4).

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CodeSmith 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:39:30
#152 ]
Elite Member
Joined: 8-Mar-2003
Posts: 3045
From: USA

@takemehomegrandma

Oooh. NOW I get it. This has been an OS4 vs MOS ####ing contest all along. Sorry, I should have realized this sooner.

We're done here.

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Jorge 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:39:39
#153 ]
Cult Member
Joined: 20-Oct-2003
Posts: 657
From: Scottsdale, AZ

@Hans

Quote:
True. The Friedens said that a MESA implementation would come once a new graphics system was in place. This should include GLSL. My point was that GLSL is a better choice than Cg.


The main reason for that is, that vmem cannot be allocated statically (e.g. GPU kernel would need that to load code, etc.). MESA includes all that in the latest 6.x version, but is heavily dependent on DRI (which includes drivers for NVidea and ATI to some extend). Problem is, DRI would take over the HW - which in case of the AmigaOS is in strong conflict with P96 which does not allow anyone else to manage memory in vmem and is not flexible enough to add this functionality.

One more thought about sharing system structures: This can be implemented thru access restrictions and exceptions, IMO. As long as a new API is used, a mech allowing legal access to data structures can be implemented, while an old code exception would copy the data into a private address space to manipulate (or whatever), still not a 100% sandbox. AllocSysObject() in OS4 is a step in that direction.

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Jorge 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:44:00
#154 ]
Cult Member
Joined: 20-Oct-2003
Posts: 657
From: Scottsdale, AZ

@CodeSmith

Would that imply that every core has its own address space ? For a plain OS4 port, is this required ? Can you sync page tables between cores ? Or does each have its own ?
(See, proves what do I know - nothing :) Say, we postpone MP for a simply SMP imp.

_________________
AmigaOne XE G3/933/VIA/FM801/R200 (fixed),
G3SE/600/Voodoo3/Sil680/RTL8139/SBLive! (noiseless!)
A1-MK2/G3/933/R200/CMI8738
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itix 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:45:34
#155 ]
Elite Member
Joined: 22-Dec-2004
Posts: 3398
From: Freedom world

@Hans

Quote:

Were people ever supposed to read that directly?


Yes they were. Commodore developers documented it like the rest of ExecBase and it is not marked private.

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CodeSmith 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:53:24
#156 ]
Elite Member
Joined: 8-Mar-2003
Posts: 3045
From: USA

@Jorge

No, no. It's like this: OS4 on single CPUs already makes use of the MMU in order to (among other things) cause an exception when reading or writing to the very first few KB of memory - this is done to catch a common programming error in C and asm. Problem is, memory address 4 contains a pointer to Exec's data and function table, so reading from address 4 is valid. That means that the code that gets run when an exception is caused needs to check if it was a read from address 4 and allow it.

The data that is pointed at by address 4 contains a lot of information about the system, including CPU-specific data. That means that there needs to be a separate copy of this data for each CPU, because some parts of it will be different for each CPU. So what would happen is that the code I mentioned in the paragraph above, which checks for address 4, would return a different value depending on the CPU that was doing the memory access.

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Hans 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:54:38
#157 ]
Elite Member
Joined: 27-Dec-2003
Posts: 4927
From: New Zealand

@itix

Quote:

itix wrote:
@Hans

Quote:

Were people ever supposed to read that directly?


Yes they were. Commodore developers documented it like the rest of ExecBase and it is not marked private.


It doesn't mean that they wanted people to use it. I thought that they were begging people to use the exec functions instead. Not marking it as private is definitely asking for trouble though. BTW, how many apps would break if we denied them access to sysbase?

Anyway, one possibility would be a separate sysbase for each core. No need to clone the OS and run a separate copy on each core, just clone a few parts. If necessary, the MMU could be used to provide the correct sysbase per core.

Another possibility with forbid/permit would be to lock the other core out of system structures (and possibly regions of shared memory) during the forbid. That way, the other core could continue running tasks that don't require access to system structures.

Hans

_________________
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https://keasigmadelta.com/ - More of my work.

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itix 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:56:03
#158 ]
Elite Member
Joined: 22-Dec-2004
Posts: 3398
From: Freedom world

@CodeSmith

Quote:

SysBase would probably have to be different for each CPU. That's not a huge deal because the first page frame has to be virtualized anyway (the null pointer detection code has to special-case address 4).


It does not work. Programs cache and pass ExecBase around and wrong programs could use wrong ExecBase. This option was brainstormed six years ago and it got scrapped quickly.

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adiaux 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 18:59:16
#159 ]
Super Member
Joined: 1-Jun-2006
Posts: 1249
From: Unknown

@ssolie

Quote:
AmigaOS is evolving beyond your little box analogy. The box is changing. The pieces are changing. Some people can't handle change and stay with the same box and pieces and are happy to play with them the way they are until they die. Enjoy your little box while the adults move on to bigger and better things.


When the box becomes "something else", when all the pieces becomes "something else", it is then when it will no longer be *Amiga*.

I have been at bigger and better things since ages, thank you. Professionally, I could not live without Windows. Only Windows has all the features I need, as well as all the applications I need, in order to earn my daily bread.

I appreciates Amiga for what it is. The Amiga as it is today (as in OS4 and MorphOS) *does* have its merits, and it could have a future, at least if you identify its strengths and its weaknesses, if you identify what it *can* be, and what it can *not* be, and make a development strategy accordingly.

If you fail doing this, and start running in all kinds of irrational directions with your OS development, then you will end up with a mess, an OS that is impossibly positioned for *any* market.

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Jorge 
Re: AckOne High-End Will Run PA Semi Multi-core
Posted on 6-May-2007 19:00:18
#160 ]
Cult Member
Joined: 20-Oct-2003
Posts: 657
From: Scottsdale, AZ

@CodeSmith

Ah, OK. But this would only be necessary for per core context (save/restore) and some other things. I don't have the Execbase in my head, but could that simply point to a cpu extension ? ThisTask shouldn't be a problem as long as the task can save/restore its context on the cpu. Well, I gotta stop here before I start talking crap. Gotta look into details to get a better idea how it could work. (there are some fundamental question if you have one scheduler or one per core and how to you handle multiple running states in the system, etc.).

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