Date: Sun, 30 Mar 2014 12:51:35 -0700 (PDT) From: "Chris H" <bsd-lists@bsdforge.com> To: "John-Mark Gurney" <jmg@funkthat.com> Cc: freebsd-stable@freebsd.org Subject: Re: where's the full copy of dmesg(8)? Message-ID: <f159c4c9d6db6e98409078b23740dcec.authenticated@ultimatedns.net> In-Reply-To: <20140330162118.GN60889@funkthat.com> References: <d3e160a01d1af1af67980b151cc57da3.authenticated@ultimatedns.net> <53378975.1000905@egr.msu.edu> <9da21869740371e51b0e684f493676ef.authenticated@ultimatedns.net> <20140330162118.GN60889@funkthat.com>
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> Chris H wrote this message on Sun, Mar 30, 2014 at 01:28 -0700: >> Greetings, Adam, and thank you for your reply. >> > On 03/29/2014 21:37, Chris H wrote: >> >> Greetings, >> >> I'm testing on 9.2-STABLE, and was experimenting on an AMD sempron >> >> (140). Booting from the boot-only, or DVD-1 DVD's doesn't emit the >> >> entire dmesg(8) output. Building, and installing a custom kernel also >> >> didn't provide the full dmesg(8) output. >> >> Specifically; it omits the top N lines (N = as yet, undetermined Number). >> >> I have no idea why, or how to correct this. I'm pretty confident >> >> the processor, and motherboard (MSI) are not too new for FreeBSD. >> > >> > I am almost certain you want to increase kern.msgbufsize at the boot >> > loader before booting. >> > >> > % sysctl -d kern.msgbufsize >> > kern.msgbufsize: Size of the kernel message buffer >> >> Interesting. Given that every system I run has (default) value of 65536. >> Can you, or anyone suggest what the correct, of better value should be? >> Or better, what the formula to determine that value is? I'm not finding >> either of those answers in the man(1) pages, or the documentation. >> >> Thanks again, for your thoughtful reply. > > Well, you're booting w/ bootverbose set, which is why you're running > out of dmesg space... choosing a default that doesn't waste memory is > hard, because some systems have complicated PCI bus layouts and many > devices, that you'd have to set it very large to be fine for all > systems, and that would be a waste on 99% of them... > > If you do find a system where a normal (non-bootverbose) boot cannot > fit in dmesg, let us know... Thank you for the reply. Indeed. I boot verbose on all the systems. Yet they all appear to have a large enough window to provide the top of the boot messages. Given that this was 9.x (others are releng_8). I thought perhaps there was a difference that caused this /apparent/ anomaly. There is a "noisy" message regarding miibus0 (32 additional lines) that appears to be a complaint. So I can easily see where this would have pushed the top of the message buffer out of the window. In the end, not having an "official" formula. I simply bumped the window size by 512, until I got the information (messages) I would normally expect to see. Thank you very much for taking the time to respond. --Chris > > Thanks. > > -- > John-Mark Gurney Voice: +1 415 225 5579 > > "All that I will do, has been done, All that I have, has not." >
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