Re: [ECOS] SMP on Intel x86

[Nick Garnett <nickg@ecoscentric.com>]

"Steve West" <swest@cyglan.com> writes:

> Hello,
>     I am still having some problems with SMP on Intel x86. I am using
> Core 2 duo CPU's with a Intel DG35EC Motherboard. Problem is that the
> Bios only reports 1 CPU entry in the MP table. I assume this is the
> boot CPU. I know this setup works ok with XP. Xp reports 2 CPU's. Is
> there somthing I am missing with the MP table?

In the 7 years since I wrote this code the state of x86 SMP technology
has moved on considerably. The MP tables are now obsolete and replaced
by ACPI tables, which is what XP is using. Most BIOSes still have an
MP table for backward compatibility, but it only describes a single
CPU.

So the first step is to add code to parse ACPI table.

However, even in 2001 SMP support was experimental and incomplete. It
was just about possible to get simple stand-alone programs up and
running, but RedBoot didn't work, none of the device drivers had been
converted to SMP awareness, some of the test programs didn't work,
debugging was difficult. Little has been done with the code since and
bitrot and changes to the rest of eCos mean that even the minimal
functionality it used to have has probably been lost.

Of course it can probably be fixed, but that is several weeks work.

There is also a question of suitability. eCos is intended for small,
cheap, low power embedded devices. Anything with a Core 2 duo in it
will have plenty of RAM, peripherals, graphics, and high power
consumption. Most likely a PC motherboard. It would make more sense to
run an embedded Linux on that than put the effort in to getting eCos
running.

-- 
Nick Garnett                                      eCos Kernel Architect
eCosCentric Limited    http://www.eCosCentric.com      The eCos experts
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