Date: Thu, 13 Jul 2000 09:33:24 +0930 From: Greg Lehey <grog@lemis.com> To: Ben Smithurst <ben@FreeBSD.ORG> Cc: doc@FreeBSD.ORG Subject: Re: small update to handbook about debug kernels Message-ID: <20000713093324.A4094@wantadilla.lemis.com> In-Reply-To: <20000712145451.D11000@strontium.scientia.demon.co.uk> References: <20000711131846.L11000@strontium.scientia.demon.co.uk> <20000712103922.A29642@wantadilla.lemis.com> <20000712145451.D11000@strontium.scientia.demon.co.uk>
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On Wednesday, 12 July 2000 at 14:54:51 +0100, Ben Smithurst wrote: > 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. That looks a lot better. I don't think it's too long. Only one thing: does the symbol lookup time increase sufficiently to be noticeable? I don't have any experience with this myself. I'd personally play safe and not mention it. Greg -- Finger grog@lemis.com for PGP public key See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-doc" in the body of the message
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