Date: Wed, 7 Apr 1999 11:41:27 +0930 From: Greg Lehey <grog@lemis.com> To: Julian Elischer <julian@whistle.com>, Archie Cobbs <archie@whistle.com> Cc: Christopher Michaels <ChrisMic@clientlogic.com>, gjb@comkey.com.au, questions@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Veto? (was: Debug kernel by default (was: System size with -g)) Message-ID: <19990407114127.Y2142@lemis.com> In-Reply-To: <Pine.BSF.3.95.990406110942.759B-100000@current1.whistle.com>; from Julian Elischer on Tue, Apr 06, 1999 at 11:11:08AM -0700 References: <199904061757.KAA73737@bubba.whistle.com> <Pine.BSF.3.95.990406110942.759B-100000@current1.whistle.com>
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On Tuesday, 6 April 1999 at 11:11:08 -0700, Julian Elischer wrote: > On Tue, 6 Apr 1999, Archie Cobbs wrote: > >> Christopher Michaels writes: >>> Maybe I'm a little out of the loop, but as a general user I feel I should >>> voice my opinions (questions). >>> >>> I understand the up-sides of a debug kernel (although I wouldn't mind some >>> clarification), but what are the down sides? >>> - The kernel is larger, correct? Is this just file size or does it take up >>> significantly more memory as well? >> >> You would install two kernels: /kernel and /kernel.debug. The first >> one is a normal kernel (but no debugging info) and this is the one >> you run. So no more memory is used (except on your disk). The second >> you only need as a debug reference for the first when you get a core dump. >> >>> - Does a debug kernel impart any performance hit? >> >> No... the same code is being executed as before. > > The down side is that you really need 32MB to compile a debug kernel > in timescales measurable by humans, and you need an extra 20MB or so of > disk per kernel compile directory. Have you tried this out? I have. I did the following on a 486DX/2-66 with 16 MB, running 2.2.6: time build directory size no symbols 34 min 5 MB symbols 44 min 25 MB So you're right about the size. I don't see a really big difference with the time; after using modern machines, it's painful either way, but people who are used to building kernels on a 386/20 with 8 MB will be delighted :-) I still definitely think that there should be a way to override the symbols for people who really insist on not having them, but I don't think that time or space are such an argument. Does anybody want to execute a power of veto, or shall I commit some changes? Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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