[systemd-devel] bootchart issues on slow hardware

Kok, Auke-jan H auke-jan.h.kok at intel.com
Mon Mar 18 11:40:21 PDT 2013

On Sun, Mar 17, 2013 at 6:54 AM, Kay Sievers <kay at vrfy.org> wrote:
> Here is a chart:
>   http://people.freedesktop.org/~kay/bootchart-20130317-1434.svg
> Rotating media and really cheap hardware looks very sad, and we take
> like 5 times longer to boot than Windows 8.

I've seen many charts like that - in most of them it appears like
readahead isn't helping at all.

> Why does bootchart stop before all the *really* slow desktop stuff starts?

There's some rework needed to make it stop in the same way that e.g.
the readahead collector works - right now it just runs for 20 seconds
or so and exits. This is on my work list to fix.

> Why does bootchart claim an idle time of ~5 sec, not that I wouldn't
> like that, but .... :)

That's when the CPU are below a certain percentage(somewhere below 1%)
for a certain time (0.5sec)... enough to call "idle". Usually this
happens when there is really slow IO. It bears no correlation to the
systemd state.


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