Kernelnewbies Digest, Vol 71, Issue 26

Kernelnewbies Digest, Vol 71, Issue 26

[Laurence Rochfort]

The BBC Micro which was 6502 based had an add on that let you connect a Z80
straight onto the same bus.

Different regards "operating system" I know, but it has been tried before.

On Fri, 21 Oct 2016, 17:00 , <kernelnewbies-request@kernelnewbies.org>
wrote:

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> Today's Topics:
>
>    1. Is that possible to implement a single machine with
>       heterogeneous     architecture. (Douglas Su)
>    2. Re: Is that possible to implement a single machine with
>       heterogeneous     architecture. (Felix Bytow)
>    3. Re: Is that possible to implement a single machine with
>       heterogeneous     architecture. (Valdis.Kletnieks at vt.edu)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 21 Oct 2016 03:10:28 +0000
> From: Douglas Su <d0u9.su@outlook.com>
> Subject: Is that possible to implement a single machine with
>         heterogeneous   architecture.
> To: kernelnewbies <kernelnewbies@kernelnewbies.org>
> Message-ID:
>         <
> SN1PR04MB2096827D49CA8F766DA1392EECD40 at SN1PR04MB2096.namprd04.prod.outlook.com
> >
>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hello everyone,
>
>
> Is that possible to install multiple CPUs which have different
> architecture on a single machine? For example, on a single machine with two
> different cpu sockets for X86 and MIPS cpu respectively, and these two cpus
> are inter-connected with some sorts of bus (PCI or other advanced buses).
>
>
> If it is possible, Is this machine still SMP? What will lscpu (or cat
> /proc/cpuinfo) dump?
>
>
> Thx!
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> Message: 2
> Date: Fri, 21 Oct 2016 06:48:16 +0200
> From: Felix Bytow <felix.bytow@googlemail.com>
> Subject: Re: Is that possible to implement a single machine with
>         heterogeneous   architecture.
> To: kernelnewbies at kernelnewbies.org
> Message-ID: <0f45ce48-02da-1e53-8341-0fc9761001ce@googlemail.com>
> Content-Type: text/plain; charset="utf-8"
>
> That question reminds me of this:
>
> https://www.kickstarter.com/projects/udoo/udoo-x86-the-most-powerful-maker-board-ever/description
>
> It is basically a hybrid of an x86 cpu and a microcontroller. Don't know
> if that counts for you^^
>
>
> Am 21.10.2016 um 05:10 schrieb Douglas Su:
> >
> > Hello everyone,
> >
> >
> > Is that possible to install multiple CPUs which have different
> > architecture on a single machine? For example, on a single machine
> > with two different cpu sockets for X86 and MIPS cpu respectively, and
> > these two cpus are inter-connected with some sorts of bus (PCI or
> > other advanced buses).
> >
> >
> > If it is possible, Is this machine still SMP? What will lscpu (or cat
> > /proc/cpuinfo) dump?
> >
> >
> > Thx!
> >
> >
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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> ------------------------------
>
> Message: 3
> Date: Fri, 21 Oct 2016 09:49:49 -0400
> From: Valdis.Kletnieks at vt.edu
> Subject: Re: Is that possible to implement a single machine with
>         heterogeneous   architecture.
> To: Douglas Su <d0u9.su@outlook.com>
> Cc: kernelnewbies <kernelnewbies@kernelnewbies.org>
> Message-ID: <51610.1477057789@turing-police.cc.vt.edu>
> Content-Type: text/plain; charset="us-ascii"
>
> On Fri, 21 Oct 2016 03:10:28 -0000, Douglas Su said:
>
> > Is that possible to install multiple CPUs which have different
> architecture
> > on a single machine? For example, on a single machine with two different
> cpu
> > sockets for X86 and MIPS cpu respectively, and these two cpus are
> > inter-connected with some sorts of bus (PCI or other advanced buses).
>
> Is it possible?  Probably.
>
> Is it worth the effort?  Probably not - I suspect that things like the
> IBM Power-based Cell architecture (used in the Playstation 3 and the
> Blue Gene supercomputers), or GPU accelerators from NVidia, are as far
> as you can reasonably stretch the idea.
>
> For starters, you'd probably *not* be able to do a full SMP (symmetric
> multi
> processing) - at best you'll probably get an asymmetric system where only
> one processor architecture can handle things like interrupts and
> scheduling,
> and one architecture basically only run userspace compute code.
>
> Going any further will end up requiring *two* copies of kernel code (one
> for
> each architecture), and figuring out how to merge the interrupt vectors
> for the two architectures.   Then you get into other ugly stuff like
> handling
> differing virtual memory layouts, keeping two sets of page tables in sync,
> and so on.
>
> And $DEITY help you if the two architectures are different endian-ness.
>
> In the dim dark past (1989-ish) I actually had to sysadmin a system that
> was a
> heterogeneous cluster - an IBM 3090 running AIX/370 and a network of
> i386-based
> IBM PS2's) running a variant of AIX 1.2, and clustering software from
> Locus,
> branded as TCF (Transparent Computing Facility).  Total nightmare for the
> sysadmin - users were *always* forgetting which node they did a compile
> on, so
> they'd end up with a bunch of .o files compile for the 3090, and some for
> i386,
> and wonder why their program wouldn't link. And that was just the *start*
> of
> the headaches - when IBM shipped AIX 3.1 for the RS/6000 Power line, we
> were
> early adopters and migrated away from TCF.
>
> I'll note that although IBM went on to support Unix-based systems on the
> System/370 architecture (AIX/ESA, and now Linux), TCF was quietly swept
> into the dustbin of history.
>
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> End of Kernelnewbies Digest, Vol 71, Issue 26
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Kernelnewbies Digest, Vol 71, Issue 26

[Valdis.Kletnieks at vt.edu]

On Fri, 21 Oct 2016 17:04:50 -0000, Laurence Rochfort said:

> The BBC Micro which was 6502 based had an add on that let you connect a Z80
> straight onto the same bus.

If I remember correctly, that one was basically an either/or - you could
boot the 6502, or the Z80, but you couldn't run both at the same time....
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Kernelnewbies Digest, Vol 71, Issue 26

[Laurence Rochfort]

Ah yes, you're correct. The Z80 ran the program and the 6502 then handled
I/O.

https://en.wikipedia.org/wiki/Tube_%28BBC_Micro%29?wprov=sfla1

On Fri, 21 Oct 2016, 18:40 , <Valdis.Kletnieks@vt.edu> wrote:

> On Fri, 21 Oct 2016 17:04:50 -0000, Laurence Rochfort said:
>
> > The BBC Micro which was 6502 based had an add on that let you connect a
> Z80
> > straight onto the same bus.
>
> If I remember correctly, that one was basically an either/or - you could
> boot the 6502, or the Z80, but you couldn't run both at the same time....
>
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omap watchdog

[Cor Peters]

Hello everybody

I was looking into an issue with the omap-wdt.c. The  watchdog driver not is 
reporting a different boot status when a reset is being triggered by the 
watchdog.

>From what I gathered, the issue is that in the omap_wdt_probe function,
pdev->dev->platform_data requires to be a reference to the PRM module,
however it has not been set, and I was wondering how this should work in 
an environment that uses the device tree method. (Link to usage:
http://lxr.free-electrons.com/source/drivers/watchdog/omap_wdt.c#L268 ).

My questions are as follows:
1) Is my assertion correct that the current method does not work when
   the driver is being initialised from an device tree instead of a old style 
   board file.
2) If that is the case, what would be the best method of fixing this 
   situation.

Thank you very much in advance.

omap watchdog

[Daniel.]

Seems a bug to me, you should post it to linux-omap :)

Regards,

2016-10-27 6:14 GMT-02:00 Cor Peters <cpeters@victronenergy.com>:
> Hello everybody
>
> I was looking into an issue with the omap-wdt.c. The  watchdog driver not is
> reporting a different boot status when a reset is being triggered by the
> watchdog.
>
> >From what I gathered, the issue is that in the omap_wdt_probe function,
> pdev->dev->platform_data requires to be a reference to the PRM module,
> however it has not been set, and I was wondering how this should work in
> an environment that uses the device tree method. (Link to usage:
> http://lxr.free-electrons.com/source/drivers/watchdog/omap_wdt.c#L268 ).
>
> My questions are as follows:
> 1) Is my assertion correct that the current method does not work when
>    the driver is being initialised from an device tree instead of a old style
>    board file.
> 2) If that is the case, what would be the best method of fixing this
>    situation.
>
> Thank you very much in advance.
>
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> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



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