JOSM rendering is very slow especially on UHD displays

[*Martin*]

After upgrading to UHD (4K) monitor I experience slow rendering in JOSM which makes mapping no more pleasant. Slowdown is higher if I move map outside of boundaries of downloaded data (see attached video) but it is also slow on normal editing, or with just panning signle layer of background imagery.

JOSM Version: 17447 (reproducible also on current josm-tested)
JRE: OpenJDK 16 (reproducible also on OpenJDK 15)
OS: Debian Bullseye
HW: Radeon RX 5500 (HW acceleration enabled), AMD Ryzen 3900X, 64GB RAM

I run JOSM like this:

java -Dsun.java2d.uiScale=2 -Dsun.java2d.opengl=True -jar ~/josm-tested.jar

In the 2nd line of the console output I see:

OpenGL pipeline enabled for default config on screen 0

Parameter -Dsun.java2d.opengl=True actually makes no difference for the speed.

[ezekielf@…]

I am also experiencing this issue. The status report below lists the scaled resolution of 2560×1440, but the native display resolution is 3840×2160. If I resize the JOSM window to around 1/4 to 1/3 of the screen, panning, zooming, and draw operations are smooth and feel similar to running JOSM on the laptop's built in display (2880×1800) or on the 1920×1200 external display I used previously. With the JOSM window filling the screen on the 3840×2160 display, panning, zooming, and draw operations are very laggy.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2022-01-02 21:24:43 +0100 (Sun, 02 Jan 2022)
Revision:18360
Build-Date:2022-01-02 20:26:19
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (18360 en) Mac OS X 12.2.1
OS Build number: macOS 12.2.1 (21D62)
Memory Usage: 519 MB / 4096 MB (239 MB allocated, but free)
Java version: 11.0.13+8-LTS, Azul Systems, Inc., OpenJDK 64-Bit Server VM
Look and Feel: com.apple.laf.AquaLookAndFeel
Screen: Display 731479689 2560×1440 (scaling 2.00×2.00) Display 731479690 2560×1440 (scaling 2.00×2.00) Display 69733382 1440×900 (scaling 2.00×2.00)
Maximum Screen Size: 2560×1440
Best cursor sizes: 16×16→16×16, 32×32→32×32
Environment variable LANG: en_US.UTF-8
System property file.encoding: UTF-8
System property sun.jnu.encoding: UTF-8
Locale info: en_US
Numbers with default locale: 1234567890 -> 1234567890
VM arguments: [-Djava.util.Arrays.useLegacyMergeSort=true, --add-exports=jdk.deploy/com.sun.deploy.config=ALL-UNNAMED, --add-opens=java.desktop/javax.swing.text.html=ALL-UNNAMED, --add-reads=java.naming=ALL-UNNAMED,java.desktop, --add-exports=java.base/sun.security.action=ALL-UNNAMED,java.desktop, --add-reads=java.base=ALL-UNNAMED,java.desktop, --add-exports=java.naming/com.sun.jndi.toolkit.url=ALL-UNNAMED,java.desktop, --add-opens=java.base/jdk.internal.loader=ALL-UNNAMED, --add-exports=java.desktop/com.apple.eawt=ALL-UNNAMED, --add-exports=java.desktop/sun.awt=ALL-UNNAMED,java.desktop, --add-opens=java.base/jdk.internal.ref=ALL-UNNAMED, --add-exports=java.base/sun.security.validator=ALL-UNNAMED,java.desktop, --add-exports=java.desktop/com.sun.imageio.plugins.jpeg=ALL-UNNAMED, --add-exports=java.base/sun.net.www.protocol.jar=ALL-UNNAMED,java.desktop, --add-exports=java.base/jdk.internal.util.jar=ALL-UNNAMED,java.desktop, --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED, --add-exports=java.base/com.sun.net.ssl.internal.ssl=ALL-UNNAMED,java.desktop, --add-exports=javafx.graphics/com.sun.javafx.application=ALL-UNNAMED, --add-modules=java.scripting,java.sql,javafx.controls,javafx.media,javafx.swing,javafx.web, --add-exports=java.desktop/sun.awt.X11=ALL-UNNAMED,java.desktop, --add-exports=java.desktop/sun.applet=ALL-UNNAMED,java.desktop,jdk.jsobject, --add-exports=java.base/sun.net.www.protocol.http=ALL-UNNAMED,java.desktop, --add-opens=java.base/java.lang=ALL-UNNAMED, --add-exports=java.base/sun.security.util=ALL-UNNAMED,java.desktop, --add-exports=java.desktop/com.sun.imageio.spi=ALL-UNNAMED, --add-reads=java.desktop=ALL-UNNAMED,java.naming, --add-opens=java.base/java.nio=ALL-UNNAMED, --add-exports=java.base/sun.security.x509=ALL-UNNAMED,java.desktop, --add-opens=java.desktop/javax.imageio.spi=ALL-UNNAMED, --add-exports=java.desktop/javax.jnlp=ALL-UNNAMED,java.desktop, --add-exports=java.base/sun.security.provider=ALL-UNNAMED,java.desktop]

Plugins:
+ FastDraw (35893)
+ apache-commons (35893)
+ apache-http (35893)
+ buildings_tools (35916)
+ conflation (0.6.9)
+ contourmerge (v0.1.8)
+ jna (35893)
+ jts (35893)
+ mapwithai (1.9.8)
+ measurement (35893)
+ shrinkwrap (v1.0.4)
+ terracer (35893)
+ todo (30306)
+ undelete (35893)
+ utilsplugin2 (35893)
+ wikipedia (605)

Map paint styles:
+ https://josm.openstreetmap.de/josmfile?page=Styles/MapWithAI&zip=1

[ezekielf@…]

I tried launching JOSM with the -Dsun.java2d.uiScale=1 flag and that made the performance much smoother. Here's a short video comparison: ​https://youtu.be/bKO1RqSx3c4
Looks to me like the UI scaling has a significant negative impact on performance.

[skyper]

General (java) system settings and the graphic card driver might come into play, here. The wrong native resolution might be an indicator.

@ezekielf:
Please, try it with java 17 and check your general java system settings. Do other java programs show the same behavior on your system?

[ezekielf@…]

I've tried with java 17 and am seeing the same behavior. I normally use JOSM via OpenWebStart and that is using java 11. What general java system settings would be useful to see? JOSM is the only java program I use, so I have nothing to compare it to.

[skyper]

Replying to ezekielf@…:

I've tried with java 17 and am seeing the same behavior.

Thanks, but not the best news as this would have been an easy solution.

I normally use JOSM via OpenWebStart and that is using java 11.

How did you install JOSM? Current macOS-package ships java 17.

What general java system settings would be useful to see?

Sorry, I have no clue about macOS. Someone else needs to answer this and probably talk off.

[taylor.smock]

I did a bit of profiling for #21901, and the hatching was surprisingly expensive when panning. I'd expect it to be the same when not panning.

[stoecker]

See ​https://github.com/JOSM/josm/pull/155