https://bugs.kde.org/show_bug.cgi?id=458491
Bug ID: 458491
Summary: gwenview - cpu inefficiency while creating thumbnails
Product: gwenview
Version: 20.12.3
Platform: Debian stable
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: general
Assignee: gwenview-bugs-n...@kde.org
Reporter: khaluk...@gmail.com
Target Milestone: ---
Created attachment 151693
--> https://bugs.kde.org/attachment.cgi?id=151693&action=edit
(strace file)
Hello guys,
I'm running Debian 11/stable and the gwenview I have is of version 20.12.3
which is like 2 years behind what it is now 😄
Today I launched it for the very first time and after leaving it idle for a
while i noticed it was maxing out CPU.
I look closer with strace and can see it does some repetitive kernel calls to
open various thubmnail files from my home dir, which do not exist. Like it's
trying to identify if there's a thumbnail exist for some image:
=== cut ==
0.000160 openat(AT_FDCWD,
"/home/pi/.cache/thumbnails/normal/c7fcf9994e28aa4446314e8d44702782.png",
O_RDONLY|O_CLOEXEC) = -1 ENOENT (No
such file or directory)
0.000370 openat(AT_FDCWD,
"/home/pi/.cache/thumbnails/normal/c7fcf9994e28aa4446314e8d44702782.png.bmp",
O_RDONLY|O_CLOEXEC) = -1 ENOENT
(No such file or directory)
0.000117 openat(AT_FDCWD,
"/home/pi/.cache/thumbnails/normal/c7fcf9994e28aa4446314e8d44702782.png.cur",
O_RDONLY|O_CLOEXEC) = -1 ENOENT
(No such file or directory)
0.000102 openat(AT_FDCWD,
"/home/pi/.cache/thumbnails/normal/c7fcf9994e28aa4446314e8d44702782.png.fit",
O_RDONLY|O_CLOEXEC) = -1 ENOENT
(No such file or directory)
0.000098 openat(AT_FDCWD,
"/home/pi/.cache/thumbnails/normal/c7fcf9994e28aa4446314e8d44702782.png.fits",
O_RDONLY|O_CLOEXEC) = -1 ENOENT
(No such file or directory)
0.000097 openat(AT_FDCWD,
"/home/pi/.cache/thumbnails/normal/c7fcf9994e28aa4446314e8d44702782.png.gif",
O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
0.000141 openat(AT_FDCWD,
"/home/pi/.cache/thumbnails/normal/c7fcf9994e28aa4446314e8d44702782.png.ico",
O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
=== end of cut ==
And all those calls are attributed to vast majority of time that app was
spending on CPU:
=== cut ==
pi@orangepi4-lts:~$ sudo strace -c -p 70014
strace: Process 70014 attached
^C
strace: Process 70014 detached
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
42.47 0.178028 11 15074 14139 openat
21.86 0.091656 25 3615 read
11.62 0.048727 8 5925 2 newfstatat
7.75 0.032476 10 3068 write
5.08 0.021315 24 862 22 faccessat
4.28 0.017959 19 945 ppoll
2.47 0.010357 11 935 close
1.37 0.005738 9 614 59 statx
1.32 0.005552 6 924 fstat
1.10 0.004626 27 168 getdents64
0.61 0.002575 9 271 ioctl
0.03 0.000109 10 10 lseek
0.01 0.000047 9 5 getuid
0.01 0.000043 8 5 geteuid
0.00 0.000012 12 1 clone
0.00 0.000000 0 2 futex
------ ----------- ----------- --------- --------- ----------------
100.00 0.419220 12 32424 14222 total
=== end of cut ==
Attaching a raw strace log as well for the period of time when this issue was
happening.
I'm guessing there's no need to try to probe each and every filetype for a
thumbnail. I'm 100% sure users are not configuring their thumbnails to be
created in different image formats.
>From the user perspective the issue is like this - when you open some folder
with big amount of images (in my case it was like few thousands) and leave it
idle, the gwenview first maxes out CPU, then goes into SWAP then system
starting to die.
I would be glad if you can give me some URL for build instructions for
gwenview, so I could check the same behavior in the most recent version. I do
have a recent experience of building a Kate :)
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