[systemd-devel] Bootchart speeding up boot time

[Kok, Auke-jan H]

On Mon, Feb 22, 2016 at 11:51 AM, Martin Townsend
<mtownsend1973 at gmail.com> wrote:
> Hi,
>
> Thanks for your reply.  I wouldn't really call this system stripped down, it
> has an nginx webserver, DHCP server, postgresql-server, sftp server, a few
> mono (C#) daemons running, loads quite a few kernel modules during boot,
> dbus, sshd, avahi, and a bunch of other stuff I can't quite remember.  I
> would imagine glibc will be a tiny portion of what gets loaded during boot.
> I have another arm system which has a similar boot time with systemd, it's
> only a single cortex A9 core, it's running a newer 4.1 kernel with a new
> version of systemd as it's built with the Jethro version of Yocto so
> probably a newer version of glibc and this doesn't speed up when using
> bootchart and in fact slows down slightly (which is what I would expect).
> So my current thinking is that it's either be down to the fact that it's a
> dual core and only one core is being used during boot unless a fork/execl
> occurs? Or it's down to the newer kernel/systemd/glibc or some other
> component.
>
> Is there anyway of seeing what the CPU usage for each core is for systemd on
> boot without using bootchart then I can rule in/out the first idea.

Not that I know of, but, to work around the issue of dynamic linking,
one can link systemd-bootchartd statically. It'll become larger, but
you can then clearly ascern that the impact of glibc bits being loaded
are properly recorded by bootchart. And, it's fairly trivial link it
statically.

Auke