I've noticed that my boot time lately has been unusually slow. I am running 12.04 a laptop with a 2.40GHz CPU and 4GB of RAM. I've run bootchart and dmesg, but I'm not sure how to use them to address the issue.

Here's the bootchart:


Here's the dmesg output (it was too long to paste here): http://pastebin.com/bspNtsux.

Any help would be much appreciated. Let me know if I can provide any more information. Thanks in advance.

  • 1
    Seems your boot performance is really IO bound. Especially ureadahead is taking almost 20 secs (!) essentially waiting for the disk...
    – alci
    Jan 18, 2013 at 8:52
  • Try disabling ureadahead and post the bootchart. I wonder if that can shave away that 20sec.
    – John Siu
    Jan 21, 2013 at 19:10
  • This might mean that your disk is slowly gtting old, and it's time for a replacement; or not.
    – Wolfer
    Jan 24, 2013 at 16:46

1 Answer 1


I don't know what boot time you are expecting, and how long it used to take on this machine. I think the ureadahead part is quite long, but I'm not sure, as I use SSDs for years now...

Anyway, you can have a look at the post http://ubuntuforums.org/showthread.php?t=1434502 which explains ureadahead.

From this post, you can try the following:

  • trigger ureadahead reprofile

    sudo rm /var/lib/ureadahead/*.pack

    then reboot once to reprofile, and once again to see the result.

  • remove ureadahead and see if things get better (they will most probably get worse, but who knows ?)

    sudo mv /etc/init/ureadahead.conf /etc/init/ureadahead.disable

    then reboot and see if things are better. To reactivate ureadhead, rename /etc/init/ureadahead.disable back to /etc/init/ureadahead.conf

Does it help ?

  • Thanks for the suggestions. Unfortunately, they don't seem to have helped. Could you explain what you meant when you said that my boot performance was IO bound?
    – Mandy
    Jan 21, 2013 at 3:06
  • 1
    This means that looking at the first part of the chart, one can see that most of the time, disk activity is at its max, while CPU is not. So CPU is waiting for disk Input /Output.
    – alci
    Jan 21, 2013 at 8:19

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