From owner-freebsd-hackers  Fri Apr  5 14:18:21 2002
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Date: Fri, 5 Apr 2002 14:18:38 -0800 (PST)
From: Doug White <dwhite@resnet.uoregon.edu>
To: Alessandro de Manzano <adm@unixmania.net>
Cc: Alfred Perlstein <bright@mu.org>, <hackers@FreeBSD.ORG>
Subject: Re: Is a debug kernel slower than a non-debug one ?
In-Reply-To: <20020405220831.B14188@libero.sunshine.ale>
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On Fri, 5 Apr 2002, Alessandro de Manzano wrote:

> On Fri, Apr 05, 2002 at 12:00:05PM -0800, Alfred Perlstein wrote:
>
> Wow, thanks for the super-fast answer! :))
>
>
> > > on my production servers' kernel so in the very rare case of crash I'll
> > > got a crash dump ( I'ld use also options DDB_UNATTENDED) and could
> > > immediately have a backtrace report.
> > >
> > > ..Am I crazy ? :-))
> >
> > I don't think you'll notice a difference for most stuff, this is how
>
> does the "-g" option (GCC option I guess) disable the "-O" optimizing
> option ?
> If "-g" simply attach the symbols and similar debug info to the
> executable I guess the kernel should not be slower, but I don't know
> GCC very well...

Note that the kernel binary with debugging symbols is left in
/sys/compile/MYKERNEL/kernel.debug while the actual kernel is stripped
before installation into /kernel.

If the debugging kernel was actually loaded it would be gigantic :)

This is all detailed in the Handbook section on kernel debugging, btw.

Doug White                    |  FreeBSD: The Power to Serve
dwhite@resnet.uoregon.edu     |  www.FreeBSD.org


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