Looking at dmesg log data - Ubuntu

This is a discussion on Looking at dmesg log data - Ubuntu ; I'm trying to understand the log that the kernel produces during boot up. Below are two fragments of what dmesg produces: ...... [ 57.460485] kjournald starting. Commit interval 5 seconds [ 57.460497] EXT3-fs: mounted filesystem with ordered data mode. [ ...

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  1. Looking at dmesg log data

    I'm trying to understand the log that the kernel produces during boot up.
    Below are two fragments of what dmesg produces:
    ......
    [ 57.460485] kjournald starting. Commit interval 5 seconds
    [ 57.460497] EXT3-fs: mounted filesystem with ordered data mode.
    [ 58.872851] usb-storage: device scan complete
    [ 58.908540] scsi 0:0:0:0: Direct-Access Maxtor OneTouch III
    0344 PQ: 0 ANSI: 4
    [ 141.767110] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
    [ 143.748135] NET: Registered protocol family 17
    [ 151.470918] Linux agpgart interface v0.102 (c) Dave Jones
    [ 151.479079] agpgart: Detected Ati IGP9100/M chipset
    ......

    [ 161.257310] lo: Disabled Privacy Extensions
    [ 171.942215] eth0: no IPv6 routers present
    [ 172.189546] ath0: no IPv6 routers present
    [ 236.275308] ACPI: Battery Slot [BAT1] (battery present)
    [ 236.597034] No dock devices found.
    [ 236.745129] input: Power Button (FF) as /class/input/input7
    .....

    Where does the time-stamp number come from? I assume it shows seconds
    elapsed from startup. There are a few major pauses, one from 58.908540
    to 1411.767110 or 72.7 seconds and a 64 second at the 172 second mark.

    I can't tell if it is the step before or the one after that's eating all
    that time. The file debug.log shows some debugging steps in network
    manager (around the 172 mark but for different days)

    Questions:
    1 Do programs like fck write to a log (under normal conditions.) or
    cause the kernel to write to its circ buffer?
    2 Where do I find out more about syslogd and sysklogd, both go to the
    same man page (sysklogd). I'm interested in how it works for ubuntu
    3 I remember seeing a ng item about testing for IPv6 gear being very
    slow when there isn't any. but can't find it any more.
    4 I'm looking for a book/howto/description to give me a good
    understanding of the many pieces that make up networking in Linux.

    Signed Confused in the Snow


  2. Re: Looking at dmesg log data

    Duinen wrote:



    > Questions:
    > 1 Do programs like fck write to a log (under normal conditions.) or
    > cause the kernel to write to its circ buffer?


    The fsck program writes to /var/log/fsck/checkfs
    and /var/log/fsck/checkroot. I'm not sure if it writes to any other
    logs.



    > 3 I remember seeing a ng item about testing for IPv6 gear being very
    > slow when there isn't any. but can't find it any more.


    From your dmesg file it looks like you don't have IPv6. I don't know
    how to test for it, but maybe someone else in here does. To blacklist
    it:

    1) Open your blacklist file:

    If you run Ubuntu:
    sudo nano /etc/modprobe.d/blacklist

    - or -

    If you run Kubuntu:
    kdesu kate /etc/modprobe.d/blacklist

    2) Add this line to the bottom of the file:

    blacklist ipv6

    3) Save the file and exit the editor.

    4) Restart the network:

    sudo /etc/init.d/networking restart

    - or-

    Reboot the computer.

    > 4 I'm looking for a book/howto/description to give me a good
    > understanding of the many pieces that make up networking in Linux.


    This is a great place for documentation:

    http://tldp.org/

    And here are a few links I recommend:

    http://littlergirl.googlepages.com/UsefulLinks.html

    --
    Little Girl

    There is no spoon.


  3. Re: Looking at dmesg log data

    Little Girl wrote:
    > Duinen wrote:
    >
    >
    >
    >> Questions:
    >> 1 Do programs like fck write to a log (under normal conditions.) or
    >> cause the kernel to write to its circ buffer?

    >
    > The fsck program writes to /var/log/fsck/checkfs
    > and /var/log/fsck/checkroot. I'm not sure if it writes to any other
    > logs.
    >
    >
    >
    >> 3 I remember seeing a ng item about testing for IPv6 gear being very
    >> slow when there isn't any. but can't find it any more.

    >
    > From your dmesg file it looks like you don't have IPv6. I don't know
    > how to test for it, but maybe someone else in here does. To blacklist
    > it:
    >
    > 1) Open your blacklist file:
    >
    > If you run Ubuntu:
    > sudo nano /etc/modprobe.d/blacklist
    >
    > - or -
    >
    > If you run Kubuntu:
    > kdesu kate /etc/modprobe.d/blacklist
    >
    > 2) Add this line to the bottom of the file:
    >
    > blacklist ipv6
    >
    > 3) Save the file and exit the editor.
    >
    > 4) Restart the network:
    >
    > sudo /etc/init.d/networking restart
    >
    > - or-
    >
    > Reboot the computer.
    >
    >> 4 I'm looking for a book/howto/description to give me a good
    >> understanding of the many pieces that make up networking in Linux.

    >
    > This is a great place for documentation:
    >
    > http://tldp.org/
    >
    > And here are a few links I recommend:
    >
    > http://littlergirl.googlepages.com/UsefulLinks.html
    >


    Thanks for your help!
    I blacklisted ipv6, but nothing happened. No error messages, no ACK no
    NAK. And most of all no reduced delay. I was going to blame it on top
    posting but I just realized it may be my other buggaboo: case sensitive
    names. I'll have to see if that does something.

  4. Re: Looking at dmesg log data

    Duinen wrote:

    > Little Girl wrote:
    > > Duinen wrote:


    > >> 3 I remember seeing a ng item about testing for IPv6 gear being
    > >> very slow when there isn't any. but can't find it any more.


    > > From your dmesg file it looks like you don't have IPv6. I don't know
    > > how to test for it, but maybe someone else in here does. To
    > > blacklist it:


    > > 1) Open your blacklist file:




    > Thanks for your help!
    > I blacklisted ipv6, but nothing happened. No error messages, no ACK
    > no NAK. And most of all no reduced delay. I was going to blame it
    > on top posting but I just realized it may be my other buggaboo: case
    > sensitive names. I'll have to see if that does something.


    If you followed the instructions, you should see a message
    in /var/log/syslog that says:

    Feb 14 09:59:42 YOURCOMPUTERNAME modprobe: WARNING: Not loading
    blacklisted module ipv6

    But it turns out that you might have wasted your time blacklisting it
    and can reverse the instructions to un-blacklist it since it likely has
    no bearing on network slowdown. I just found this page and if you read
    Yagisan's messages, he makes a lot of sense. If your slowdown is in
    Firefox, he has easy instructions on how to fix it. And if he's right,
    Ubuntu is handling IPv6 for you, so it's not the operating system
    that's the problem - it's the individual programs. It sounds like he
    knows what he's talking about, so it's worth a look:

    http://ubuntuforums.org/archive/index.php/t-87798.html

    --
    Little Girl

    There is no spoon.

  5. Re: Looking at dmesg log data

    Little Girl wrote:
    > Duinen wrote:
    >
    >> Little Girl wrote:
    >>> Duinen wrote:

    >
    >>>> 3 I remember seeing a ng item about testing for IPv6 gear being
    >>>> very slow when there isn't any. but can't find it any more.

    >
    >>> From your dmesg file it looks like you don't have IPv6. I don't know
    >>> how to test for it, but maybe someone else in here does. To
    >>> blacklist it:

    >
    >>> 1) Open your blacklist file:

    >
    >
    >
    >> Thanks for your help!
    >> I blacklisted ipv6, but nothing happened. No error messages, no ACK
    >> no NAK. And most of all no reduced delay. I was going to blame it
    >> on top posting but I just realized it may be my other buggaboo: case
    >> sensitive names. I'll have to see if that does something.

    >
    > If you followed the instructions, you should see a message
    > in /var/log/syslog that says:
    >
    > Feb 14 09:59:42 YOURCOMPUTERNAME modprobe: WARNING: Not loading
    > blacklisted module ipv6


    I do get the message. It helps if you know where to look.
    >
    > But it turns out that you might have wasted your time blacklisting it
    > and can reverse the instructions to un-blacklist it since it likely has
    > no bearing on network slowdown. I just found this page and if you read
    > Yagisan's messages, he makes a lot of sense. If your slowdown is in
    > Firefox, he has easy instructions on how to fix it. And if he's right,
    > Ubuntu is handling IPv6 for you, so it's not the operating system
    > that's the problem - it's the individual programs. It sounds like he
    > knows what he's talking about, so it's worth a look:
    >
    > http://ubuntuforums.org/archive/index.php/t-87798.html
    >


    To me it's not a waste if I learned something, which I have. The lengthy
    pauses I'm seeing during bootup are not network related. Maybe the next
    dmesg line [ 240.719069] ACPI: Battery Slot [BAT1] (battery present)
    has something to do with it.

    Thanks for the link. That is the one I had seen but could not find.

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