Bug 363621

Summary:	Krita 3.0 is slower than 2.8
Product:	[Applications] krita	Reporter:	sunwebrw
Component:	OpenGL Canvas	Assignee:	Krita Bugs <krita-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	griffinvalley, halla
Priority:	NOR
Version First Reported In:	3.0 Release Candidate
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description sunwebrw 2016-05-28 07:33:12 UTC

Hi, i was testing 3.0 version from official appimage you provided. Comparing to 2.8 from Kubutnu 14.04 repositories its alot slower. The settings are the same. It doesn't matter if OpenGL enabled/disabled, on 2.8 everything is fast on 3.0 everthying is slow, i can clearly see how line is drawing way after i made a stroke.
Also it crashes when enabling/disabling OpenGL. Maybe it crashes elsewhere as well.
I am using Radeon HD5770 GPU with the latest OSS drivers available from official repositories.

Reproducible: Always

Steps to Reproduce:
0. If you have powerful GPU then choose the size of canvas where its on a border of good and bad performance for 2.8 version and use the same settings for 3.0
1. Open Krita and choose "Basic block" brush, you can use any other brush that is not as simple as the default one
2. Make a fast stroke from(for example) left upper corner to right lower one
3. See how it draws that line when your mouse stopped

Actual Results:  
Slowly draws a line after some time i've made a stroke.

Expected Results:  
Instantly drawing the line following my mouse movements, like in 2.8 version.

Comment 1 wolthera 2016-05-28 19:20:49 UTC

which git hash is your 3.0 build from? (you can find the hash in help->about Krita)

Comment 2 sunwebrw 2016-05-28 20:23:44 UTC

Help about Krita shows its RC1.
Here is the one i've downloaded:
http://files.kde.org/krita/3/linux/krita-3.0-RC-1-master-6f75b0f-x86_64.appimage.mirrorlist

Comment 3 sunwebrw 2016-06-01 04:38:03 UTC

Tried http://files.kde.org/krita/3/linux/krita-3.0-x86_64.appimage
Its not crashing on changing OpenGL enabled/disabled anymore but it is still slow.

Comment 4 Halla Rempt 2017-09-28 14:28:41 UTC

I'm sorry, but there just isn't much we can do with a report like this. Krita 3.x uses a new version of the Qt toolkit, which probably influences some performance characteristics, and we cannot go back to an older version. In general, Krita 3.x is faster for most people, but it's impossible to figure out why that's not the case for everyone.