Date: Thu, 01 Apr 1999 21:22:11 +1000 From: Stephen McKay <syssgm@detir.qld.gov.au> To: Greg Lehey <grog@lemis.com> Cc: freebsd-hackers@freebsd.org, syssgm@detir.qld.gov.au Subject: Re: Debug kernel by default (was: System size with -g) Message-ID: <199904011122.VAA19831@nymph.detir.qld.gov.au> In-Reply-To: <19990331165139.W413@lemis.com> from Greg Lehey at "Wed, 31 Mar 1999 16:51:39 %2B0930" References: <19990331165139.W413@lemis.com>
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On Wednesday, 31st March 1999, Greg Lehey wrote: >To answer your question: a typical (partially) stripped kernel is >about 1.8 MB in size. The corresponding debug kernel is about 9 MB >(since ELF; a.out debug kernels are about 3 MB larger). This space is >*in memory at all times*, so you don't normally want to load it, but >it's good to have for dump analysis. I think you are slightly out of date. As a test, I just built a debugging kernel and booted my 4.0 box *without* the normal 'strip -g kernel' bit. The old kernel and the new: (Yes, only up to #32 on this box!) -rwxr-xr-x 2 root wheel 8138961 Apr 1 19:05 /kernel -rwxr-xr-x 1 root wheel 1625374 Mar 18 20:09 /kernel.31 -rwxr-xr-x 2 root wheel 8138961 Apr 1 19:05 /kernel.32 The old kernel boot messages (from kernel.31): ... Mar 19 19:12:19 twoflower /kernel: CPU: i486 DX2 (486-class CPU) Mar 19 19:12:19 twoflower /kernel: Origin = "GenuineIntel" Id = 0x435 Stepping =5 Mar 19 19:12:19 twoflower /kernel: Features=0x3<FPU,VME> Mar 19 19:12:19 twoflower /kernel: real memory = 16777216 (16384K bytes) Mar 19 19:12:19 twoflower /kernel: avail memory = 13926400 (13600K bytes) Mar 19 19:12:19 twoflower /kernel: Preloaded elf kernel "kernel" at 0xc02a9000. ... The new kernel boot messages (from kernel.32): ... Apr 1 20:31:48 twoflower /kernel: CPU: i486 DX2 (486-class CPU) Apr 1 20:31:48 twoflower /kernel: Origin = "GenuineIntel" Id = 0x435 Stepping =5 Apr 1 20:31:48 twoflower /kernel: Features=0x3<FPU,VME> Apr 1 20:31:48 twoflower /kernel: real memory = 16777216 (16384K bytes) Apr 1 20:31:48 twoflower /kernel: avail memory = 13914112 (13588K bytes) Apr 1 20:31:48 twoflower /kernel: Preloaded elf kernel "kernel" at 0xc02ac000. ... So it's 13600KB vs 13588K, which is pretty much the same. So, I think that ELF doesn't load the symbol table. From now on I'm going to build a bigger root partition and keep monster debugging kernels. Stephen. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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