Bug 1400417 - unwanted cache flush in Freetype engine
Summary: unwanted cache flush in Freetype engine
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Fedora
Classification: Fedora
Component: qt5-qtbase
Version: 25
Hardware: x86_64
OS: Linux
unspecified
high
Target Milestone: ---
Assignee: Than Ngo
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2016-12-01 07:29 UTC by Maxim Prohorenko
Modified: 2017-07-26 06:49 UTC (History)
5 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2017-07-26 06:49:13 UTC
Type: Bug

Attachments (Terms of Use)
Patch from QT git (1.19 KB, patch)
2016-12-01 07:29 UTC, Maxim Prohorenko 		no flags Details | Diff
View All Add an attachment (proposed patch, testcase, etc.)


Links
System ID Private Priority Status Summary Last Updated
Qt Bug Tracker QTBUG-49452 0 None None None 2016-12-01 07:31:15 UTC

Description Maxim Prohorenko 2016-12-01 07:29:30 UTC 
Created attachment 1226647 [details]
Patch from QT git

Description of problem:

QT 5 font rendering very slow.

Need fix form qt:

REG: Fix unwanted cache flush in Freetype engine
6f423555eba55ccdf7287071e10576bc1b687fd2

Version-Release number of selected component (if applicable):

Fedora 25

Installed Packages
Name        : qt5
Arch        : noarch
Epoch       : 0
Version     : 5.7.0
Release     : 9.fc25
Size        : 9.0 k
Installed Packages
Name        : qt5-qtbase
Arch        : x86_64
Epoch       : 0
Version     : 5.7.0
Release     : 3.fc25
Size        : 8.3 M
Repo        : @System


How reproducible:
100% load 1 core in Glyph rendering.
If use nvidia driver - GL context freez.
If use nouveau - system too slow.

Steps to Reproduce:
0. Set text anti-aliasing Enable->Full
1. Open kwrite
2. Open qtbase-opensource-src-5.7.0/src/gui/doc/src/richtext.qdoc
3. Switch font to inconsolata
3. Scroll, slow
4. Switch font to consolas
5. Scroll, very slow!


Actual results:
QFontEngineFT::alphaMapForGlyph in top of callgrind

alphaMapFromGlyphData

Fonts very slow


Expected results:
Fast fonts, smooth scrolling.

Additional info:
Apply patch, rebuild qt5-qtbase* .rpm, speedup system.
Comment 1 Rex Dieter 2016-12-01 14:37:35 UTC 
A qt-5.7.1 bugfix update that includes this fix is being worked on.
Comment 2 Than Ngo 2017-07-26 06:49:13 UTC 
it's fixed in latest qt5-qtbase-5.7.1-19 which was pushed into stable f25 last week.
Note You need to log in before you can comment on or make changes to this bug.