From mboxrd@z Thu Jan 1 00:00:00 1970 From: lucas.magasweran@ieee.org (Lucas Rangit Magasweran) Date: Fri, 24 May 2013 07:16:23 -0700 Subject: Bootloader sequence with time prefix (Kernelnewbies Digest, Vol 30, Issue 24) In-Reply-To: <36844.1369060821@turing-police.cc.vt.edu> References: <36844.1369060821@turing-police.cc.vt.edu> Message-ID: <519F7637.6090303@ieee.org> To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org On 05/20/2013 07:40 AM, Valdis.Kletnieks at vt.edu 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. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20130524/88394228/attachment-0001.html