Long boot

John Hubbard ender8282 at yahoo.com
Sat Dec 20 05:43:16 UTC 2008

H.S.Rai wrote:
>  I had to disable SATA native support.
Why did you have to disable SATA support? I have a machine that I game 
on and it supports SATA without problems. It doesn't sound like SATA is 
your problem thought (read below).
> Normal working is also slow. Firefox, OO windows dimmed too frequenty
> and I have to wait to get response. Most of time HDD's activities make
> be believe that I am working on PC-XT m/c.
Are you running out of RAM and swapping to disk? This could cause 
problems slowdown...
> Now load average  for 1, 5, 15 minutes is 3.72, 4.11, 3.28
This seems really high. What is running and taking up all of you cpu 
time? I had a problem with my machine at work and it turned out that the 
machine frantically swapping memory out.

>> Can you install 'bootchart'?
> Here is output:
> http://picasaweb.google.co.in/hardeep.rai/SOSM#5281656923430016034
> http://picasaweb.google.co.in/hardeep.rai/SOSM#5281656938938897634
Thanks for posting those but unfortunately I could not quite make those 
out. (Resolution was too low). If you look at the graphs you can see 
that everything stops for a while (i.e. no disk IO and no cpu 
utilization). What was 'running' while nothing was happening? Can you 
mail me one off list the pictures (ender8282 at yahoo.com)? I don't think 
it matters which one just so I can read the text.
> It is installed. But It is there with default setting, as I was not aware of it.
Hopefully someone with more knowledge will correct me on this if I am 
wrong but... I believe that you have to boot once with the flag 
'profile' attached to your kernel options. Profiling creates a list of 
the files needed to boot so that the machine can fetch the files before 
it needs them. Since fetching files is 'slow' it is better to have them 
cached and waiting. I assume that if you never profile your boot then 
the readahead list is empty and in a fraction of a millisecond your 
machine finishes running it and moves on to the next step in the boot 
sequence. I am not sure on this though. Maybe readahead is smarter than 
I am (many things are).

Even though I couldn't make out everything on the bootchart it is claer 
that you are not waiting on disk IO or on the CPU so there is something 
else wrong.


To be or not to be, that is the question
                2b || !2b
(0b10)*(0b1100010) || !(0b10)*(0b1100010)
        0b11000100 || !0b11000100
        0b11000100 || 0b00111011
        255, that is the answer.

More information about the ubuntu-users mailing list