Ubuntu 7.10 on a Laptop slow startup

[Derek Broughton]

Robert Spanjaard wrote:

> On Fri, 28 Dec 2007 19:01:11 -0800, NoOp wrote:
> 
>>> Quite often slow boots are the symptom of timeouts and DHCP/DNS lookups
>>> from routers when that informations is superfluous.
>>> 
>>> Before digging into this with any great gusto, you could try installing
>>> bootchart and analysing or posting links to the resulting png files it
>>> produces - these will show you exactly where the delays are occurring in
>>> your machine.
>> 
>> I've always found issues with bootchart:
>> 
>> 1. It causes the system to boot slower (due to creating the chart) 2.
>> I've never been able to interpret just what it is showing. Nice graphic,
>> but can't view much as it's such a large png and there doesn't seem to be
>> any help/explanation as to what you are looking at.
>> 
>> Take http://www.arumes.com/temp/gutsy-20071228-2.png for example; what
>> exactly does that png show? How do you read it?
> 
> Don't you see the blue bar labeled "usplash"?
> 
>> http://www.arumes.com/temp/gutsy-20071228-1.png seems to be somewhat
>> better, but again, how do you read it and determine what is the cause of
>> the slow startup?
> 
> That long blue bar from the other chart is _missing_ in this one, because
> the splkashscreen is disabled.
> 
>> IMHO asking someone to install bootchart doesn't help much unless you
>> provide details as to what they should be looking for in the bootchart.
> 
> The legends are at the top of the chart. This was the first time I used
> it, without any help, and IMO it's quite easy to see (at least partly)
> what's causing the problem. Ofcourse a chart doesn't tell the whole story
> (_why_ is usplash using so much CPU-power?), but it's a good start.
> 
I agree.  I have never used bootchart, but I looked at your two graphics
they seemed obvious and I completely agree with your analysis. I can't
imagine _why_ but there are long periods in the usplash version where
nothing _but_ usplash is running.  My first thought was that the boot
process had probably finished, but you were still only seeing the splash,
but then I realized there was a time slot early on where only usplash was
working.  From what I understand, one of the big time consumers
is "readahead" - and that seems true from your graphics - but when usplash
is running, it starts much later.

And yes, sure bootchart makes the system boot slower (I've no idea if it is
enough extra time to be noticeable), but the relative difference between
the usplash/nousplash boots is still obvious. 
-- 
derek