Fedora 16 beta vice Knoppix

Lennart Poettering mzerqung at 0pointer.de
Wed Oct 5 13:09:57 UTC 2011


On Tue, 04.10.11 19:38, Adam Williamson (awilliam at redhat.com) wrote:

> 
> On Tue, 2011-10-04 at 15:53 -0800, Jef Spaleta wrote:
> > On Tue, Oct 4, 2011 at 3:32 PM, JB <jb.1234abcd at gmail.com> wrote:
> > > Let me append "The Blame Game".
> > > # systemd-analyze blame
> > >  32983ms livesys.service
> > >  22828ms NetworkManager.service
> > 
> > That timing for NM is so vastly different than what I'm seeing on my
> > installed F15 system. I am intrigued.
> 
> His numbers are all huge as he's booting live, either from an actual
> rotating shiny disc thing (the antiquity of it all!) or a USB stick.
> Either of which is going to be slower than an HD or SSD.

If this is indeed a boot from CD then it's not really surprising our
numbers are bad since seek times on CDs are awful. If people want to
spend optimizing the boot time here it should be possible to reorder the
files on the squashfs image to minimize seeking. mksquashfs has the
-sort option for that. The data would have to be generated in a two-pass
way: first burn and boot the unordered image, use it to determine the
access order, then pass that to mksquashfs and generate a second,
ordered image. You could use systemd-readahead-collect to collect that
access order information, but you'd need to write a tool to convert
systemd's format to something readable by mksquashfs.

Optimizations like this are always thinkable, but then again spending
the time on optimizing CD boots sounds like a lot of time wasted on
yesterday's technology.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.


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