[KPhotoAlbum] KPhotoAlbum crashes while generating thumbnails during start

[Manfred Usselmann]

Am 06.05.2013 23:10, schrieb Johannes Zarl: 

> On Monday 06 May
2013 22:35:39 Johannes Zarl wrote:
> 
>> I didn't find anything yet in
the strace.log, but I'll keep you posted.
> 
> Ah, just as I was done
sending the other mail, I noticed something: There are 
> some file
accesses to some path under "/mnt/server/...". Are your files lying 
>
on an nfs share, by any chance?
> 
> I imagine that the thumbnail
creation (hitting on a lot of files) may not play 
> along well with a
high-latency storage. AFAIK the ImageManager cancels 
> thumbnail
requests for low-priority thumbnails when others are more urgent. If 
>
you add a high-latency storage into the mix and start scrolling/browsing
your 
> images, most thumbnail requests are probably cancelled before
they start.
> 
> Maybe the long time spent in futexes could also mean
that KPA gets preempted a 
> lot because of NFS being too slow (for
KPA's heavy access patterns). Is it 
> only KPA that becomes slow, or
does it tear down the performance of other 
> desktop programs or the
file manager?

The share is a Windows share (Samba) on a local server
and mounted with the cifs file system. It's usally not slow, no issue at
all with other programs. After loading KPA there are few background
jobs, but they are done quickly. KPA starts becoming slow later even
when I wait until the background jobs are done. 

For testing I select a
path with 25 images (jpegs 1.3 MP, about 300 kB per file). The
thumbnails are displayed very fast. But when I double click on a
thumbnail it takes a while for the detail window to appear (This time:
34 seconds until the image is visible, sometimes it's a bit faster).
PgDn is sometimes fast for a few pictures (e.g. 5 to 6), then there is a
longer delay (typically 5 - 10 seconds). Closing the detail window
sometimes takes very long, but right now it did close immediately.
Clicking on 'Back' takes quite long, opening the 25 image tumbnails
again takes longer than initially (about 10 secs). 

It looks like there
is a lot more network traffic going on than one would expect. All the 25
pictures together are only 7,5 MB. 

For comparison I opened the folder
on the mounted share directly with the default file manager, doubled
clicked on the first image, which opens it with eog and scrolled thru
the images with PgDn. This is fast as lightning. No delay at all.


Manfred 
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