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