[systemd-devel] Improve boot-time of systemd

[Tomasz Torcz]

On Wed, Apr 20, 2011 at 02:43:36AM +0200, Lennart Poettering wrote:
> On Fri, 18.03.11 13:40, Gustavo Sverzut Barbieri (barbieri at profusion.mobi) wrote:
> 
> > 
> > On Fri, Mar 18, 2011 at 10:52 AM, Andrey Borzenkov <arvidjaar at mail.ru> wrote:
> > > On Fri, Mar 18, 2011 at 12:35 PM, fykcee1 at gmail.com <fykcee1 at gmail.com> wrote:
> > >> Hi all,
> > >>
> > >> We did a series boot-time tests of systemd, and found some interesting things:
> > >> (Note the tests were performed on a laptop with a 4-core mips cpu, AMD
> > >> RS780 chipset, 2GB Memory, rotate harddisk with ext4 filesystem,
> > >> debian squeeze, Linux 2.6.36 with fanotify enabled, systemd-v20, only
> > >> boot to console.)
> > >>
> > >> 1. What can readahead affect boot-time?
> > >> Sadly observed negative affect -- boot-time increases at least 1s.
> > >
> > > From subjective feelings (no real measurements) I confirm it.
> > 
> > I noticed it as well, even with my Macbook Pro i7 with 8Gb RAM and
> > 128SSD using btrfs.
> 
> Note that btrfs is actually not particularly fast when mounting.

> We do serialization of fsck on rotating media already. This might be
> something that fixes itself as soon as the btrfs mounting isn't as slow
> anymore as it currently is.

  You can speed up btrfs mounting with free space caching.  Right now it is
enable with -o space_cache mount option. But beware: there was some problem
identified when free space reporting.  I am not sure if fix went to .38 and
.39-rc already.

-- 
Tomasz Torcz                 "God, root, what's the difference?"
xmpp: zdzichubg at chrome.pl         "God is more forgiving."