On Tue, 2004-11-30 at 15:20 -0500, David Malcolm wrote: > On Sun, 2004-11-28 at 20:49 -0500, David Zeuthen wrote: > > Awesome! So... is no-one else going to reply to this email? > > Various comments inline below... > Thanks! > > Hey, > > > > So, I've looked a bit more into the booting process and how to optimize > > it. Mostly based on the discussion triggered by Owen's boot poster > > challenge, here > > > > http://www.redhat.com/archives/fedora-devel-list/2004-November/msg00447.html > > > > and also some experiments that I did - basically replacing rhgb with gdm > > as described here > > > > http://www.redhat.com/archives/fedora-desktop-list/2004-November/msg00066.html > > > > What I've done is a bit crude - I've replaced init(1) with a shell > > script based on /etc/rc.d/rc.sysinit and tried to optimize specifically > > for my system: IBM Thinkpad T41 laptop with a Pentium M processor at > > 1600MHz along with 512MB of RAM. > > If I understand, you're also optimising for a specific user of that > system. Yeah, out of 5189 files (193MB), 231 of them (31MB) are from my home directory. Due to the way I've instrumented the kernel (printk() in fs/namei.c function link_path_walk()) this also includes files that are only stat(2)'ed. Which means that e.g. /home/davidz/Desktop/Stuff/kernel-2.6.9-1.751_EL.i686.rpm of size approx 10MB are loaded. So 193MB is a bit high, however, since files are being stat(2)'ed anyway there will be a disk seek to the inode so to play it safe we need that block as well. Thus, readahead would be better to do on the block layer level; also because shared objects like e.g. libgtk-x11-2.0.so contains a lot of deprecated API's nobody uses anyway (e.g. don't load those pages). > Is it worth splitting the readahead into a system-wide list of > files (enough to get to the login screen), followed by a per-user list > for logging in as a user? Could be done, yeah. > To what extent will the files needed to get > to a usable desktop vary between Alice and Bob? I dunno; if Bob uses, say, 50MB worth of .pdf documents every time he logs in we should preload those (that isn't at all out of the ordinary if Bob uses a lot of reference manuals). The list of files (blocks) should be generated from several criteria including how often they are read. Ideally we always start a daemon in early boot to monitor this and rearrange blocks on the disk when idle or perhaps every week. > > d. The whole init(1) procedure seems dated; perhaps something more > > modern built on top of D-BUS is the right choice - SystemServices > > by Seth Nickell comes to mind [1]. Ideally services to be started > > would have dependencies such as 1) don't start the gdm service > > before /usr/bin/gdm is available; 2) the SSH service would only > > be active when NetworkManager says there is a network connection; > > /usr from LABEL=/usr would only be mounted when there is a volume > > with that label and so forth. Also, such a system would of course > > have support for LSB init scripts. > > (This is probably a whole project on it's own so I'm omitting > > detailed thinking on it for now) > > Hopefully this could also allow us to make system-config-services look a > lot slicker. I've never liked the way it has random text spewage for > each service's status - some kind of widgetry would satisfy my eye-candy > cravings. > Heh, and sweet icons too :-) Cheers, David
