Bug 419075

Summary:	okular is very slow with pdf files
Product:	[Applications] okular	Reporter:	humufr
Component:	PDF backend	Assignee:	Okular developers <okular-devel>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	aacid, yurchor
Priority:	NOR
Version:	1.9.3
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description humufr 2020-03-21 13:41:15 UTC

SUMMARY


STEPS TO REPRODUCE
1. open a 'large' pdf with images (it is easier to see it) like that one: 

https://www.dropbox.com/s/qcxcbyyppg8p2ui/DRAGONS-GuideDuJoueur.pdf?dl=0

2. Read the document 


OBSERVED RESULT

It is slow to draw a page. It took seconds to do it and it is increasing little by little and the CPU usage is going through the rough. I remove every option I can to improve the performance but nothing change. I tried with evince and the problem is not there.

EXPECTED RESULT

Smooth reading of pdf file.

SOFTWARE/OS VERSIONS

Linux/KDE Plasma: 
(available in About System)

Arch Linux

KDE Plasma Version: 5.18.3
KDE Frameworks Version: 5.68.0
Qt Version: 5.14.1

ADDITIONAL INFORMATION

Processor: 12 x intel Core I7-8750H
Memory: 15,2 GiB of RAM

Comment 1 Albert Astals Cid 2020-03-21 13:47:21 UTC

Okular doesn't do any PDF rendering by itself. If PDF rendering is slow please open a bug at poppler issue tracker https://gitlab.freedesktop.org/poppler/poppler/issues/new?issue

Comment 2 humufr 2020-03-21 18:00:02 UTC

As I mention it does not happen with evince so it coule be poppler but the qt specific part. I will be surprised that I am the only one affected but I have a workaround (using evince).

Comment 3 Yuri Chornoivan 2020-03-21 19:38:53 UTC

Quick testing (Core 2 Duo E4700, SSD Kigston A400, 6GB of RAM). Fit page to width, time to load 14th page from the first page, cold start.

Poppler-based viewers:

Okular 1.10.70 (poppler 0.86.1) - 10 secs
Evince 3.32.1 - 5 secs
qpdfview 0.4.18beta - 10 secs

Non-popler-based:

MuPDF 1.16.1 - 1 sec
FoxIt Reader for Linux 2.4.4.0991 - 1 sec

Comment 4 humufr 2020-03-28 13:21:16 UTC

Issue open on poppler as asked. I cannot see why this bug has been closed with 'resolved upstream'. Perhaps it is true but without more information on the commit or solved issue on poppler it is difficult to be sure that the problem will not be forgotten and that will be a shame. Okular used to be the best pdf reader on linux and going to evince is kind of going backwards but the rendering problem is killing okular (I am pretty sure that most of the okular usage is to open pdf file).

https://gitlab.freedesktop.org/poppler/poppler/-/issues/899