debugging kernel options (was: Re: 6.2-PRE: Fatal Trap?)
freebsd at orchid.homeunix.org
Sat Dec 30 10:26:12 PST 2006
Robert Watson wrote:
>> P.S. out of curiosity - now that I have configured kernel with DDB and
>> KDB options, is there any performance penalty of running such kernel?
> No, it shouldn't really have any effect on performance. The one thing
> to watch out for is that your system will no longer reboot automatically
> on a panic, as it will drop to the debugger, by default. You can change
> this by setting debug.debugger_on_panic to 0, in which case you will
> likely want to set debug.trace_on_panic to 1 so it prints a stack trace
> before rebooting (which is often sufficient, combined with the trap
> frame and panic message to debug the problem).
> Right now these are sysctls, not tunables, but you can change the
> default using options KDB_UNATTENDED (which flips the default to not
> entering the debugger and rebooting) and options KDB_TRACE (which causes
> a trace to be printed on panic by default). Probably they should also
> be tunables so that loader.conf entries will work.
Great explanation, thank you. I turned on debugging on my desktop
computer which, apart from normal every day use, is 'testing' STABLE by
running it :) I'm perfectly fine with the defaults, at least for now.
Cheers and thanks again,
Karol Kwiatkowski <freebsd at orchid dot homeunix dot org>
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 250 bytes
Desc: OpenPGP digital signature
Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20061230/8080aa32/signature.pgp
More information about the freebsd-stable