Date: Wed, 12 Jul 2000 14:54:51 +0100 From: Ben Smithurst <ben@FreeBSD.org> To: Greg Lehey <grog@lemis.com> Cc: doc@FreeBSD.ORG Subject: Re: small update to handbook about debug kernels Message-ID: <20000712145451.D11000@strontium.scientia.demon.co.uk> In-Reply-To: <20000712103922.A29642@wantadilla.lemis.com> References: <20000711131846.L11000@strontium.scientia.demon.co.uk> <20000712103922.A29642@wantadilla.lemis.com>
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Greg Lehey wrote:
> I think you should look from the viewpoint of the modern kernel:
>
> If you are using version 2 or 3 of FreeBSD, you will need to strip
> the kernel manually... Note that if you run an a.out kernel with
> debugging symbols, the whole kernel will be loaded into memory...
Is this better:
<para>If you are using FreeBSD 3 or earlier, you should make a stripped
copy of the debug kernel, rather than installing the large debug
kernel itself:</para>
<screen>&prompt.root; <userinput>cp kernel kernel.debug</userinput>
&prompt.root; <userinput>strip -g kernel</userinput></screen>
<para>This stage isn't necessary, but it is recommended. (In
FreeBSD 4 and later releases this step is performed automatically
at the end of the kernel <command>make</command> process.)
When the kernel has been stripped, either automatically or by
using the commands above, you may install it as usual by typing
<command>make install</command>.</para>
<para>If you install and boot the debug kernel, without stripping
it as described above, symbol table lookup time for some programs
will drastically increase. Note also that older releases of
FreeBSD (up to but not including 3.1) used a.out kernels by
default, which must have their symbol tables permanently resident
in physical memory. With the larger symbol table in an unstripped
debug kernel, this is wasteful. Recent FreeBSD releases use ELF
kernels where this is no longer a problem.</para>
? It's a bit longer, but has a bit more detail, I think.
--
Ben Smithurst / ben@FreeBSD.org / PGP: 0x99392F7D
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