On Tue, Jul 6, 2010 at 2:45 AM, Willie Wong <ww...@math.princeton.edu> wrote: > On Mon, Jul 05, 2010 at 02:17:26PM -0700, Mark Knecht wrote: >> On Mon, Jul 5, 2010 at 12:11 PM, Willie Wong <ww...@math.princeton.edu> >> wrote: >> > On Mon, Jul 05, 2010 at 09:16:14AM -0700, Mark Knecht wrote: >> >> I'm trying to capture the full boot log when booting from the Gentoo >> >> install CD but it seems the buffer isn't deep enough to get the whole >> >> thing. Is there by chance a command line option that will increase the >> >> depth of what's captured by dmesg so that I can get all the way back >> >> to the beginning? >> > >> > pass the following parameter to the kernel on GRUB/LILO: >> > >> > log_buf_len=n >> > >> > where n is a power of two. By default it is 16384. You can change it >> > to 131072 (= 2^17) to get a much larger kernel log ring buffer. If you >> > put in something that is not a power of two, the kernel will ignore >> > the option. >> > >> In my normal booting kernel (on the system hard drive) I did push >> the length up to 18. With that setting dmesg prints all the way back >> to the beginning. However booting the Live CD I hit F1, it shows the >> kernels, so I type >> > > to add to the confusion is probably the fact that the in-kernel > configuration parameter is a bit-shift number, and the boot-time > cmdline parameter is actually 2 to that power. So the in-kernel > configuration parameter should be k (=18 in your case), and the > boot-time parameter should be 2^k (=262144).
Which is exactly why I chose 18 and not 262144. My bad. I switched to 262144 and now I'm getting all the dmesg data back to the very beginning. Thanks! Cheers, Mark
