https://github.com/yasuenag/ulviewer
Log viewer for Unified JVM Logging
https://github.com/yasuenag/ulviewer
gclog java9 jvm jvm-logging log-parser ul
Last synced: 3 months ago
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Log viewer for Unified JVM Logging
- Host: GitHub
- URL: https://github.com/yasuenag/ulviewer
- Owner: YaSuenag
- License: lgpl-3.0
- Created: 2016-12-13T13:21:04.000Z (about 9 years ago)
- Default Branch: master
- Last Pushed: 2025-03-15T08:22:34.000Z (9 months ago)
- Last Synced: 2025-04-11T02:31:08.844Z (9 months ago)
- Topics: gclog, java9, jvm, jvm-logging, log-parser, ul
- Language: Java
- Size: 195 KB
- Stars: 19
- Watchers: 3
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
UL Viewer
===================
UL Viewer is log parser for [JEP 158: Unified JVM Logging](http://openjdk.java.net/jeps/158) and [JEP 271: Unified GC Logging](http://openjdk.java.net/jeps/271).
# How to use
## Start application
### Linux x64
```
$ cd ulviewer--Linux-amd64/bin
$ ./ulviewer
```
### Windows x64
* Run `ulviewer.bat`
* If your machine has WSL (Windows Subsystem for Linux), you can run `ulviewer` directly.
* `ulviewer` is shell script.
## Open log(s)
You can open several logs from [File] -> [Open Log] menu.
## Log parser wizard
After selecting logs, Log parser wizard is shown.
You can choose log decorations for parsing. [Field value] column shows the value of decoration. You can choose decoration format on [Decoration] column. [Decoration] is [ChoiceBox](https://docs.oracle.com/javase/8/javafx/api/javafx/scene/control/ChoiceBox.html), so you can choose Unified JVM Logging official log decorations.
After that, you can push [OK] button.
## Check your logs!
Your logs are shown in main window.
* You can set filters through log decoration. You can choose decoration from [ComboBox](https://docs.oracle.com/javase/8/javafx/api/javafx/scene/control/ComboBox.html), and check on [CheckBox](https://docs.oracle.com/javase/8/javafx/api/javafx/scene/control/CheckBox.html).
* If you want to search logs with some keywords, you can search it through search window.
* Copy selected log entry when you press CTRL+C.
### Drawing chart
If you want to draw chart(s), you have to add tag(s) which indicates time to `-Xlog` option as below:
* `time` (`t`)
* `utctime` (`utc`)
* `uptime` (`u`)
* `timemillis` (`tm`)
* `uptimemillis` (`um`)
* `timenanos` (`tn`)
* `uptimenanos` (`un`)
In addition, you have to add `tags` (`tg`) to log tags.
#### Java heap chart
* [Chart] -> [Memory] -> [Java heap]
* You need to open `info` level log (`gc=info`).
* You can check Java heap memory. This chart shows all STW collection (all major/minor GCs)
* You can also check specific GC events when you click the plot on the chart.
#### GC pause time chart
* [Chart] -> [Memory] -> [Pause time]
* You need to open `info` level log (`gc=info`).
* You can check GC STW time.
* You can also check specific GC events when you click the plot on the chart.
#### Metaspace chart
* [Chart] -> [Memory] -> [Metaspace]
* You need to open `info` level log (`gc+metaspace=info`).
* You can check Metaspace usage and capacity. This chart shows Metaspace GC event.
#### CodeCache chart
* [Chart] -> [Memory] -> [CodeCache]
* You need to open `debug` level log (`compilation+codecache=debug`).
* You can check CodeCache usage. This chart stacks CodeCache usage by segments (non-profiled nmethods, profiled nmethods, non-nmethods).
> [!NOTE]
> UL Viewer would use the value of free memory in `compilation+codecache=debug` - it might be different from actual free size.
> Both CodeCache Sweeper (~ JDK 19) and GC (for CodeCache: JDK 20~) use free list like CMS GC to manage reclaimed CodeBlob (for nmethod), it does not affect free memory in CodeCache. Free memory in `compilation+codecache=debug` shows unallocated memory only.
#### Class histogram
* [Chart] -> [Memory] -> [Class histogram]
* You need to open `trace` level log (`gc+classhisto*=trace`).
* You can check class histogram when Full GC is invoked.
#### VM Operations
* [Chart] -> [VM Operations]
* You need to open `debug` level log (`vmoperation=debug`).
* You can check all VM operations.
### Show data table
#### Class loading/unloading
* [Table] -> [Class loading]
* You need to open `debug` level log for class loading, and need to open `info` level log for class unloading (`class+load=debug,class+unload=info`).
* You can check class loading / unloading information.
#### Age table
* [Table] -> [Age table]
* You need to open `trace` level log (`gc+age=trace`).
* You can check age table when GC is invoked.
# How to build
You have to use JDK 17 or later.
```
$ mvn package
```
# License
The GNU Lesser General Public License, version 3.0