[systemd-devel] Can bootchart take advantage of startup completed signal?

Lennart Poettering lennart at poettering.net
Wed Feb 13 11:08:25 PST 2013

On Wed, 13.02.13 09:27, Umut Tezduyar (umut at tezduyar.com) wrote:

> Hi Auke,
> I was wondering if you have tried to take advantage of StartupFinished
> signal sent by systemd (
> http://www.freedesktop.org/wiki/Software/systemd/dbus).
> Would it make sense to register on "StartupFinished" signal and stop taking
> measurements when systemd boots up completely? This would be an alternate
> to "samples=" option. "samples=" option is great but one needs to know how
> long does their system take to boot up so that one can do the math by
> dividing boot up time by freq= option of bootchart. Even then this would be
> a rough estimate.
> Since bootchart starts even before dbus, you won't be able to register for
> the StartupFinished signal until the bus is ready. Registration could be
> done in the bootchart's while loop where the measurements are taken. Then
> the question is, would registration attempts take too much resource?

As Auke mentioned we probably should leave bootchrt running for a
while even after the boot from systemd's view is finished. 

I'd suggest to follow the same scheme how we kill the readahead
collector a few seconds after boot completed, with a timer unit.


Lennart Poettering - Red Hat, Inc.

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