Bug 296768

A modern linux should be very responsive with only 80% load, what it can make it slow is exceed memory and so start using swap or disk usage.
Anyway try:
ionice 3 nice digikam
to make it use only spare cpu and disk to see if help

For me, this is not reproducible here (i5 computer). Cleaning all thumbnails DB, and rebuild it (250 Gb of images) do not break computer like this. It still suitable as well.

Gilles Caulier

I would see it as a bug if digikam only uses 20% for a CPU-intensive task - that means it does not use the available hardware.
Now thumbnail regeneration is older code, multithreaded but not prepared for multicore. In fact, there is only one thread. (code can be optimized by removing the need to generate a pixmap - this is only a toy for the progress dialog - and using the prepare... method).

So while I would like to see the thumbnail creation make use of all you four core, it cannot at the moment, and a load of 80% means load on all four cores. Which tool did you use to measure per-process or per-thread CPU use?

Under Kubuntu 11.10, I use system Monitor, showing only "CPU". It
appears to be an average value of the overall load.

If possible, I´d linke to provide more detailed information- just don´t
know, how.

Axel

Am 26.03.2012 21:39, schrieb Marcel Wiesweg:
> https://bugs.kde.org/show_bug.cgi?id=296768
> 
> --- Comment #3 from Marcel Wiesweg <marcel.wiesweg@gmx.de> ---
> I would see it as a bug if digikam only uses 20% for a CPU-intensive task -
> that means it does not use the available hardware.
> Now thumbnail regeneration is older code, multithreaded but not prepared for
> multicore. In fact, there is only one thread. (code can be optimized by
> removing the need to generate a pixmap - this is only a toy for the progress
> dialog - and using the prepare... method).
> 
> So while I would like to see the thumbnail creation make use of all you four
> core, it cannot at the moment, and a load of 80% means load on all four cores.
> Which tool did you use to measure per-process or per-thread CPU use?
>

Dilles:

what specific info do you need for reproducing?

By the way: what is "suitable" for your understanding? if you make one
single click and you have to wait for seconds before reaction- if any?


Axel

Am 25.03.2012 23:20, schrieb Gilles Caulier:
> https://bugs.kde.org/show_bug.cgi?id=296768
> 
> Gilles Caulier <caulier.gilles@gmail.com> changed:
> 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                  CC|                            |caulier.gilles@gmail.com
> 
> --- Comment #2 from Gilles Caulier <caulier.gilles@gmail.com> ---
> For me, this is not reproducible here (i5 computer). Cleaning all thumbnails
> DB, and rebuild it (250 Gb of images) do not break computer like this. It still
> suitable as well.
> 
> Gilles Caulier
>

Francesco,

what is "ionice 3 nice digikam"?

I have no idea. So sorry.


Axel
Am 25.03.2012 23:16, schrieb Francesco Riosa:
> https://bugs.kde.org/show_bug.cgi?id=296768
> 
> Francesco Riosa <francesco+kde@pnpitalia.it> changed:
> 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>              Status|UNCONFIRMED                 |NEEDSINFO
>                  CC|                            |francesco+kde@pnpitalia.it
>          Resolution|---                         |WAITINGFORINFO
> 
> --- Comment #1 from Francesco Riosa <francesco+kde@pnpitalia.it> ---
> A modern linux should be very responsive with only 80% load, what it can make
> it slow is exceed memory and so start using swap or disk usage.
> Anyway try:
> ionice 3 nice digikam
> to make it use only spare cpu and disk to see if help
>

(In reply to comment #6)
> Francesco,
> what is "ionice 3 nice digikam"?
> I have no idea. So sorry.

ionice - set or get process I/O scheduling class and priority
  (make the acces to the disk of a particular program wait for other processes finish their work)
nice - run a program with modified scheduling priority
  (make the usage of the cpu of a particular program wait for other processes to do their work)
basically composing the command like that digikam will be the last to use disk and cpu
you may need to install them and to launch digikam from the command line (a shell)

Axel, this very much seem a system problem, more than a digikam problem.
you may be more lucky in the ubuntu forums, possibly
http://ubuntuforums.org/forumdisplay.php?f=331

try asking there specifying the kubuntu version, the file system used for /home, maybe the digikam version, and other programs which are running at the same time

Not reproducible with 6.0.0