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alci
Asked: 2013-01-14 03:08:28 +0800 CST

How may I improve my boot / shutdown time?

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I have a pretty decent laptop (Intel Core i7-3520M CPU @ 2.90GHz, SataII SSD from Samsung, 8GB Ram), but I not satisfied with my boot and shutdown times... I have installed bootchart, and am trying to interpret it, but I don't understand some parts.

Bootchart output

In particular, I don't get what is happening during the first 10 seconds, when there is almost no CPU utilization, nor I/Os. What is happening then ? (there seem to be only udevd, modprobe and plymouth running).

On the other end of my daily work, I also experiente slow shutdown. No shotdown chart here, so I'm even more clueless...

Update I have come accross a hint saying hitting the up key while shutting down gives access to the console (I had been fighting with F1 / Alt F1 before that). So I have seen that the long shutdown time seems to have to do with rpcbind and modem-manager being unable to quit cleanly... Any idea?

Update 2 I have uninstalled rpcbind, as well as modemmanager. This made things better for shutdown, but I still have several seconds waiting between the 'All processes ended within 1 seconds' message, and the real shutdown. Just then, I get a quick message I was unable to read yet, but I suspect some sort of timeout to occur...

Update 3 Ok, I think I have narrowed things down to the execution of resume and wait-for-root during the first 10 seconds of the boot process. This is taking more than 5 secs, with no disk nor noticable CPU activity. I noticed that swap UUID in /etc/initramfs/conf.d/resume does not match with the real UUID of my swap partition, which happens to be... crypted. Maybe that is the point ? Any hint on initramfs-tools and cryptswap ?

12.10

2 Answers

  1. Best Answer

    Ok, I have found the problem. As I was feeling, the 5 seconds waiting on resume and wait-for-root is not normal.

    Googling around, I finally found this bug report: 5 second delay on wait-for-root

    Essentially, it states that the 5 secs wait is due to a wrong entry in /etc/initramfs-tools/conf.d/resume.

    It turns out that my swap is encrypted, and I had the initial installation UUID in /etc/initramfs-tools/conf.d/resume. I tried to put the one given by blkid for /dev/mapper/cryptswap1, but it didn't work...

    I finally just commented out the entry in the file, and the 5 seconds delay is gone. Any way, hibernate is not enabled on my system (I think it is disabled by default in Ubuntu). Notice the # at the beginning of the entry.

    #RESUME=UUID=3835540d-0cb4-46fc-b39a-de9ff88dcefd

    then run:

    sudo update-initramfs -u

    So here is my latest bootchart:

    bootchart

    Much better. Regarding shutdown, removing rpcbind and modemmanager did the trick. I now have great boot and shutdown times.

    • 12

  2. Maybe you would want to consider installing your OS on RAM? If real speed is what you are after then that would be it. The difference between SSD loadtime and RAM loadtime is just huge.

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