F13: Delay in screen refresh
Marco Guazzone
marco.guazzone at gmail.com
Mon May 31 09:24:55 UTC 2010
On Mon, May 31, 2010 at 10:51 AM, Mike Fleetwood
<mike.fleetwood at googlemail.com> wrote:
[... cut ...]
> Hi Marco,
>
> I'm no expert but it sound to me like you have a latency issue. For
> some reason your machine is sometimes having to wait 1 to 4 seconds
> before it can give a program (vim, bash, etc.) its CPU time slice,
> hence the apparent delay.
>
> I have seen this kind of thing before when the kernel has to re-try
> disk I/O multiple times on a failing hard drive.
>
> Suggestions:
> 1) Play music! If it pauses when your app pauses it is an OS wide
> issue effecting everything.
I will try tonight at home
> 2) Run top in another window. When top refreshes after the pause does
> any process jump to the top?
No process seems to have a great impact on CPU usage.
These below are the more time consuming processes:
1563 root 20 0 172m 42m 11m S 3.6 2.1 4:39.59 Xorg
2751 marco 20 0 942m 173m 30m S 3.6 8.7 4:32.69 firefox
2790 marco 20 0 419m 19m 10m S 2.0 1.0 2:11.23 npviewer.bin
After refresh, Xorg goes from 1.0 to 2.5 % of CPU. This percentage
increase to ~16% when I switch between wm virtual desktops.
> 3) Check /var/log/messages for any errors.
>
Done, but no meaningful information (or maybe I don't know what to look for).
> Vague ideas:
> 4) Google for investigating latency issues.
> 5) With modern kernels I guess it should be possible to dynamically
> trace it to find the lateny issue, but I have no idea how.
>
> Sorry I can't be more help,
> Mike
Thank you very much for your help.
Hope someone other can help me :)
In addition to system information provided in previous email I add
that my notebook is a DELL Latitude D830
Cheers,
-- Marco
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