Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/mgm3746/vmcat
A command line tool to parse Java -XX:+LogVMOutput safepoint statistics.
https://github.com/mgm3746/vmcat
java-support openjdk support-jvm-tuning
Last synced: 2 months ago
JSON representation
A command line tool to parse Java -XX:+LogVMOutput safepoint statistics.
- Host: GitHub
- URL: https://github.com/mgm3746/vmcat
- Owner: mgm3746
- License: epl-2.0
- Created: 2020-09-09T13:44:59.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2023-10-24T15:06:10.000Z (about 1 year ago)
- Last Synced: 2023-10-24T16:30:56.745Z (about 1 year ago)
- Topics: java-support, openjdk, support-jvm-tuning
- Language: Java
- Homepage:
- Size: 492 KB
- Stars: 2
- Watchers: 2
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# vmcat
A command line tool to parse Java -XX:+LogVMOutput and do analysis to support JVM tuning and troubleshooting for OpenJDK and Oracle JDK.
## Supports
OpenJDK8 derivatives:
* AdoptOpenJDK
* Azul
* Microsoft Build of OpenJDK
* Oracle JDK
* Red Hat build of OpenJDK
* etc.
### Recommended JVM Options
>-XX:+UnlockDiagnosticVMOptions -XX:+PrintSafepointStatistics -XX:PrintSafepointStatisticsCount=1 -XX:+LogVMOutput -XX:LogFile=/path/to/vm.log
## Building
Get source:
```
git clone https://github.com/mgm3746/vmcat.git
```
Build it:
```
cd vmcat
mvn clean (rebuilding)
mvn assembly:assembly
mvn javadoc:javadoc
```
## Usage
```
java -jar vmcat-1.0.2-SNAPSHOT.jar --help
usage: vmcat [OPTION]... [FILE]
-h,--help help
-l,--latest latest version
-o,--output output file name (default report.txt)
-t,--threshold threshold (0-100) for throughput bottleneck
reporting
-v,--version version
```
Notes:
1. By default a report called report.txt is created in the directory where the **vmcat** tool is run. Specifying a custom name for the output file is useful when analyzing multiple vm logs.
1. Version information is included in the report by using the version and.or latest version options.
1. Preprocessing is sometimes required (e.g. when non-standard JVM options are used). It removes extraneous logging and makes any format adjustments needed for parsing (e.g. combining logging that the JVM sometimes splits across multiple lines).
1. If threshold is not defined, it defaults to 90.
1. Throughput = (Time outside safepoint) / (Total Time). Throughput of 100 means no time spent in safepoint (good). Throughput of 0 means all time spent in safepoint (bad).
## Report
```
========================================
Throughput less than 5%
----------------------------------------
822.685: RevokeBias [ 3077 0 0 ] [ 0
0 0 15 0 ] 0
822.703: BulkRevokeBias [ 3077 0 1 ] [ 0
0 0 15 58 ] 0
...
4190.458: RevokeBias [ 3085 0 4 ] [ 0
0 1 14 0 ] 0
4190.475: BulkRevokeBias [ 3085 0 1 ] [ 0
0 0 13 39 ] 0
========================================
JVM:
----------------------------------------
Version: OpenJDK 64-Bit Server VM (25.201-b09) for linux-amd64 JRE (1.8.0_201-b09), built on Mar
5 2019 10:14:09 by "mockbuild" with gcc 4.4.7 20120313 (Red Hat 4.4.7-23)
Options: -Xms4G -Xmx4G -XX:+UnlockDiagnosticVMOptions -XX:MetaspaceSize=512M
-XX:MaxMetaspaceSize=1024M -XX:+PrintSafepointStatistics -XX:PrintSafepointStatisticsCount=1
-XX:+LogVMOutput -XX:LogFile=vm.log -verbose:gc -Xloggc:gc.log -XX:+PrintGCDetails
-XX:+PrintGCTimeStamps -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintGCApplicationStoppedTime
-XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=5 -XX:GCLogFileSize=10M
========================================
SUMMARY:
----------------------------------------
Throughput: 88%
Max Pause: 3.121 secs
Total Pause: 900.246 secs
First Timestamp: 0.159 secs
Last Timestamp: 7677.815 secs
========================================
TRIGGERS:
----------------------------------------
# Time (s) Max (s)
ParallelGCFailedAllocation 8491 613.913 68% 3.121
RevokeBias 13007 225.595 25% 1.118
BulkRevokeBias 725 45.937 5% 0.592
no vm operation 535 9.594 1% 0.074
ParallelGCSystemGC 38 2.902 ~0% 0.352
ForceSafepoint 73 1.388 ~0% 0.046
Deoptimize 97 0.917 ~0% 0.084
EnableBiasedLocking 1 ~0.000 ~0% ~0.000
========================================
```
## Copyright
Copyright (c) 2020-2023 Mike Millson
All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse Public License - v 2.0 which accompanies this distribution, and is available at https://www.eclipse.org/legal/epl-2.0/.