IMHO, protected memory is far more important than multicore support.

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@ssolie

>We are still working on utilizing the built-in local bus support for Xena.

Any possibility to get more details?

-does xena have DMA access to system RAM?
(to me it seems possible that xena can communicate with DMA services of PA6T, but it is not 100% clear from specs so far)

-what kind of bandwidth has been seen between PA6T and xena?
(I believe it's absolute maximum is around 30MB/s)

@Trevor

Is decision made about xena on next HW release?
-does the next board have xena as well?
-does the next board have xorro?
-does the next HW have more easily accessible xena I/O?
-is the next HW going to be shipped with xorro I/O board?

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@WolfToTheMoon

I think it would be very cool to be able to start AOS4 in experimental memory protected mode.
I wonder if something like that is in the plans, IIRC, some mp stuff was put in ExecSG.

(Linux has taught me that MP does not make the system stable, you should also have stable services and apps. +it's not nice that linux usually kills missbehaving apps without any notice, I rather see GrimReaper, save what I was doing, reboot+restore in three seconds.)

Last edited by KimmoK on 05-Dec-2012 at 08:25 AM.
Last edited by KimmoK on 05-Dec-2012 at 08:24 AM.

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@broadblues

You know, that's really interesting. We really shouldn't be complaining about lack of things that Windows also lacks. Unfortunately a lot of software that has been ported to Windows only work within Cygwin, but using the same solution on AmigaOS is somehow considered "not Amiga-ish enough".

Actually, I've come to realize what a bunch of whiners we really are.

Even this post is whining about something :-p

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Quote:

ssolie wrote: @coriolis Quote: Can we expect for SMP at the new versions of AmigaOS 4? I think that is stupid to release a quite expensive X1000 and don't make support for SMP and Xena. Yes, you can expect multi-core support in AmigaOS 4.

So this means that there'll be no SMP support, but something like AMP.
Quote:

Xena support is already available via the xena.resource. We are still working on utilizing the built-in local bus support for Xena.

The XCore is good to be used as a microcontroller, but it's almost useless for other purposes.

A 30MB/s local bus is too slow, and we don't even know its latencies.

128KB of total RAM (code and data; splitted into 64KB for each core) is too little to make something interesting.

IMO it doesn't have sense to spend time with the XCore. In most cases the PA6T core(s) will do the job MUCH faster than, and without the strong effort required by the XCore protocol communication and programming (you have a new processor to study and learn how to code with it).

Last edited by cdimauro on 09-Dec-2012 at 09:11 AM.

@cdimauro

Quote:

So this means that there'll be no SMP support, but something like AMP.

I don´t think that was meaning of ssolies´ words. Sure, you can be right, or not.

@pavlor

Many guys have talked about SMP, AMP, and even BMP. He wrote "multicore" instead. That's enough for me to think that at least SMP will not be supported.

But Solie can be more clear, of course, talking about what kind of multicore support will be implemented.

@cdimauro

Quote:

SMP, AMP, and even BMP. He wrote "multicore" instead.

Since all three of those are multi-core support of some kind, there is no logic in assuming any 1 of them is more true than the other.

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@broadblues

SMP is the most useful, but the much more difficult to implement, especially for an Amiga / like o.s..

Hiding information after so much time when people, instead, speaks clearly about the terms, let me think that you don't want to know that you are working to the less compelling multicore model.

@cdimauro

It's useless to try to read between the lines an other simular OS, Linux has SMP support and so, its not unlikely AmigaOS will to, Linux is based on concept of Unix, and so is AmigaOS but from TRIPOS a UNIX vagient.

All the protection mechanisms are in place to preserve synchronicity between one or more cores are already in place whit in the OS, I really se no need to go AMP, when system is prefectly to support SMP.

AMP was some thing they where forced to do on WarpUP because the OS at the time did not support PowerPC, only when programs where designed to run inside WarpUP is was possible to take advantage of the CPU power.

While whit SMP the OS and all its tasks as scheduled on different cores, I might point out that there has been talked about updarting the task schedular I by Thomas or Hans-Jürgen in AmiWest 2011, I belive.

The biggest problem now there is so mutch technology going in to the OS, at the same time, and development team is not that big, it seams to me its more important to get current hardware supported.

And so the current issues we are having whit composition and OpenGL has addressed first, you can't build on shaky foundation.

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@cdimauro

AmigaOS was one of the first operating systems if not the first operating system that truly was multitasking, so many of issues whit synchronicity between programs (tasks & processes) is not unknown.

It might be that we see programs miss behaving that did not before, or the system might get more unstatable, who knows, but at end of the day programs will be better written, and this issues will decrees, and we get more CPU power to play whit.

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Quote:

NutsAboutAmiga wrote: @cdimauro It's useless to try to read between the lines an other simular OS, Linux has SMP support and so, its not unlikely AmigaOS will to, Linux is based on concept of Unix, and so is AmigaOS but from TRIPOS a UNIX vagient.

Tripos wan't a Unix variant: it was a different o.s..

The Amiga o.s. used only some part of Tripos, for AmigaDOS and some commands.

Kickstart/Workbench had nothing to do with Unix, albeit the ASCII character 0x0a to mark the EOL, and the / used as path separator.
Quote:

All the protection mechanisms are in place to preserve synchronicity between one or more cores are already in place whit in the OS, I really se no need to go AMP, when system is prefectly to support SMP.

How can you state this? The Amiga o.s. lacked SMP support from the beginning.

Take a look at ExecBase and at some (critical) vars that can be poked by any application at any time, without using any protection or synchronization mechanism.
Quote:

NutsAboutAmiga wrote: @cdimauro AmigaOS was one of the first operating systems if not the first operating system that truly was multitasking, so many of issues whit synchronicity between programs (tasks & processes) is not unknown.

See above: they are pretty well known, and are very difficult to be solved without breaking compatibility with existing software.
Quote:

It might be that we see programs miss behaving that did not before, or the system might get more unstatable, who knows, but at end of the day programs will be better written, and this issues will decrees, and we get more CPU power to play whit.

SMP support is not as easy as you can think. The o.s. must be changed to make it possible without making disasters. It's not easy, since the Amiga o.s. was written without any protection in mind, even for its system structures.

@cdimauro

Quote:

SMP support is not as easy as you can think. The o.s. must be changed to make it possible without making disasters. It's not easy, since the Amiga o.s. was written without any protection in mind, even for its system structures.

We used to hope for miracles.

@cdimauro

Memory protection was not the type of protection I was taking about, you don't need memory protection to make application synchronize data, its different mechanism.

Quote:

Take a look at ExecBase and at some (critical) vars that can be poked by any application at any time, without using any protection or synchronization mechanism.

It as always been stated when poking system structures you need to use Permit() and Forbid(), this includes all lists.

Quote:

See above: they are pretty well known, and are very difficult to be solved without breaking compatibility with existing software.

Most programs supports it already, Permit() and Forbid() has worked perfectly well, on a single core CPU's.

Last edited by NutsAboutAmiga on 09-Dec-2012 at 01:55 PM.

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@pavlor

Quote:

pavlor wrote: @cdimauro Quote: SMP support is not as easy as you can think. The o.s. must be changed to make it possible without making disasters. It's not easy, since the Amiga o.s. was written without any protection in mind, even for its system structures. We used to hope for miracles.

Miracles, or MMU help?

@cdimauro

The MMU has nothing to do whit it, look up atomic operations.

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Quote:

NutsAboutAmiga wrote: @cdimauro Memory protection was not the type of protection I was taking about, you don't need memory protection to make application synchronize data, its different mechanism.

You need it on Amiga o.s. / like, because system structures are easily accessible by any program.

So, you need to protect / arbiter their access.
Quote:

Quote: See above: they are pretty well known, and are very difficult to be solved without breaking compatibility with existing software. Most programs supports it already, Permit() and Forbid() has worked perfectly well, on a single core CPU's.

Calling those APIs can be easily tracked, but programs can directly access system structures such as the nested tasks counter.

It wasn't forbidden by Commodore, and macros were available to skip the APIs calls (saving some clock cycles).

The same applies to Enable() and Disable().

Quote:

NutsAboutAmiga wrote: @cdimauro The MMU has nothing to do whit it, look up atomic operations.

Atomic operations can be used on same cases (semaphores, mutexes), but not to protect (all) system structures, as I said before.

@ssolie

Hey Steven,
Thanks for taking the time to address these questions.

For any of you who aren't aware of his work, he's one of the developers assisting Hans-Joerg and Thomas.

With people like this doing the software and Trevor paying for hardware development, OS4 has an advantage over the other NG OS'.

I expect to see lower cost systems being introduced in the future by A-eon.

@cdimauro

Quote:

Calling those APIs can be easily tracked, but programs can directly access system structures such as the nested tasks counter.

That has nothing to do whit SMP support or not, if the program is writen by idiot then its writen by a idiot.

If you accessing functions whit in libraries directly, whit out calling OpenLibrary, then your probely to lazy to even think about incrementing and decrementing the lib counter.

Quote:

It wasn't forbidden by Commodore, and macros were available to skip the APIs calls (saving some clock cycles).

Your are allowed to access system structures if you do it whit forbid() and premit(), the only problem is that some of structures might change and so its written in the header files.

And your absolutely forbidden not to use forbid and permit when reading any system structure.

Even when your sending a break signal you need to call forbid()!

Forbid();
task = FindTask(“HelloWorld”);
Signal(task,SIGBREAKF_CTRL_C);
Permit();

Last edited by NutsAboutAmiga on 09-Dec-2012 at 04:56 PM.
Last edited by NutsAboutAmiga on 09-Dec-2012 at 04:54 PM.
Last edited by NutsAboutAmiga on 09-Dec-2012 at 04:46 PM.

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