Re: Bootloader sequence with time prefix (Kernelnewbies Digest, Vol 30, Issue 24)

Lucas Rangit Magasweran <lucas.magasweran@xxxxxxxx> · Fri, 24 May 2013 07:16:23 -0700



    On 05/20/2013 07:40 AM, Valdis.Kletnieks@xxxxxx
      wrote:
      

      On
        Mon, 20 May 2013 15:07:33 +0530, Dhyan said:
        

        I was working on to measure boottime for  bootime
          optimization.
          

        The bootloader is probably not where you're going to find places
        to optimize.
        

        It's got two jobs to do - load the kernel and load the initrd.
        And it's usually
        

        pretty optimized to do that. About all you can do there is
        minimize the size of
        

        the kernel and initrd so there's less to load (and move to SSD
        if you're really
        

        hardcore).
        

        The only other place to really win in the boot loader is to set
        the "hit any
        

        key to go to the boot menu" timeout to 0 or 1 seconds.  Of
        course, this means
        

        you have little (or zero) chance to enter an alternate kernel or
        commandline.
        

      Valdis is absolutely right.
      

      In case the boot loader is not so optimized or you are trying to
      reduce the boot time by milliseconds try using a GPIO pin and a
      USB logic analyzer (e.g. Salea Logic). Toggle a pin at key places
      in the boot sequence to measure time. Setting up a timer and
      printing relative time over a serial port will negatively impact
      your boot time.
      

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