slow start up Ubuntu 14.04

[Oliver Grawert]

hi,
Am Montag, den 19.05.2014, 14:22 +0200 schrieb Gary J. Kirkpatrick:

> 
> try this-
> 
> 
> https://www.dropbox.com/s/q9a9zbebd6hdqze/gary14-trusty-20140519-2.png
> 

wow even our ubuntu phones boot faster  ... 
http://people.canonical.com/~ogra/touch-bootcharts/ubuntu-phablet-utopic-39.png

so if you compare your bootchart to mine above you will notice that your
CPU effectively does nothing (you want the whole CPU graph to be as blue
as possible during the boot phase so you make use of all resources you
have...)
your system spends 7-8 sec in the initrd and kernel bringup (this ends
at the first vertical dashed line) 
then i see ureadahead doing a lot of nothing because your disk is
already utilized fully (the second graph at the top (disk throughput)
shows your harddisk maxes out at 35MB/s already ... thats a bit low) 

so as a first action try to disable ureadahed on your system, it is
supposed to load everything in one go into ram usually but your disk
cant cope with that (see in my bootchart how there is a big pink block
above ureadahead in the disk throughput graph and later on only
occasional reads happen throughout the rest of the process)

echo manual | sudo tee -a /etc/init/ureadahead.conf

do the above as a first step to disable ureadahead, that should give you
~10seconds of wasted time back ...

i sadly need to do something else now but will ponder a bit over your
bootchart for other obvious bits ... after all though your disk is way
to slow for a USB 3.0 device, i would expect more than 35MB/s from it,
it forces your CPU into constant I/O wait states ... this might point to
a kernel driver issue with USB 3.0 or the usb-storage module.

the big gap between 44 and 51 seconds where your system just seems to
completely idle surely also deserves attention here ... 

ciao
	oli
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