From owner-freebsd-current  Wed Feb 17  5:33:56 1999
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Date: Wed, 17 Feb 1999 08:33:53 -0500 (EST)
From: Luoqi Chen <luoqi@watermarkgroup.com>
Message-Id: <199902171333.IAA28121@lor.watermarkgroup.com>
To: julian@whistle.com, luoqi@watermarkgroup.com
Subject: Re:  SMP and SO5.0
Cc: current@FreeBSD.ORG, doconnor@gsoft.com.au
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> I've gone through these patches and I can see that they are really needed
> for SMP where address spaces are shared.
> 
> There are details I didn't get, such as where is the per-processor
> pde pointed, (i.e. where is the per processor KVM range) and is there a
> single page table for each processor that is
> always mapped into the processor specific slot for that process.
> 
I didn't change any of these (that's main reason I chose to have multiple
page directories over a single page directory with a different slot for
each processor and reference the per-processor data through a pointer
in processor local storage, e.g. %fs, which is simply too complicated
without compiler support. In fact I like the 2nd way better), so the
process specific slot is still MPPTDI (KVM 0xff800000-0xffbfffff?).

> another question that is raised I guess is how do we tell gdb to switch
> between processors when reading core-dumps :-).
> 
Tor has sent me a patch which implements a "cpu" command allowing you
to switch among cpus. I've never actually used it, in most of the cases,
you don't really care on which cpu the crash occurred. If you want to
try it, I can send a copy of the gdb patch to you.

-lq


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