JDK 11

Safepoints and Garbage Collector log file analyzer

Whole page is under heavy development, it is tested mostly on G1/Parallel GC on JDK 11. If you have any issues with your log file send me message to ks@gclogs.com.
Current limitations:
  • Logs from JDK 11, 12, 13 - works with flags below, tested on Parallel, CMS and G1.
  • Logs from JDK 9, 10 - should work.
  • Logs from JDK 8 and below - experimental (no GC log support, only safepoint, charts and stas are not accurate, because log file style sucks).
  • Max 10MB file (after compression).
  • For JDK 11+ decorators: level,tags,time,uptime are needed, check sample Xlog configuration below.
  • Max 1 file in compressed archive (will analyze first if there are many).
  • UI is ugly.
  • UI is optimized for Full HD resolution.
  • There is no exception handling at all :)


Import from file ...

File to upload:

Compress logs (*.zip, *.gz, *.xz, *.7z) for fast uploads.

... or paste log here

Log to upload:

Unified logger, changing logs at runtime example:

sudo -u JVM_USER jcmd `pgrep -x java` VM.log
output="file=/PATH/TO/gc.log"
output_options="filesize=104857600,filecount=5"
what="codecache+sweep*=trace,class+unload,class+load,os+thread,safepoint,gc*,gc+stringdedup=debug,gc+ergo=trace,gc+age=trace,gc+phases=trace,gc+humongous=trace,jit+compilation=debug"
decorators="level,tags,time,uptime,pid

VM Args that I use
-Xlog:codecache+sweep*=trace,
class+unload,
class+load,
os+thread,
safepoint,
gc*,
gc+stringdedup=debug,
gc+ergo=trace,
gc+age=trace,
gc+phases=trace,
gc+humongous=trace,
jit+compilation=debug
:file=/tmp/app.log
:level,tags,time,uptime
:filesize=104857600,filecount=5

Simplest VM Args to add JDK > 8
-Xlog:safepoint,
gc*,
gc+heap=trace,
gc+age=trace,
gc+phases=trace,
gc+humongous=trace
:file=/tmp/app.log
:level,tags,time,uptime

Simplest VM Args to add JDK <= 8
-XX:+PrintSafepointStatistics
-XX:PrintSafepointStatisticsCount=1
-XX:LogFile=/tmp/app.log
-XX:+LogVMOutput


Terms of service: Files you are going to upload will be stored on author server, and can be used by author for his purposes. This page is created for author purposes, use it at your own risk.
Author: Krzysztof Ślusarski Email: ks@gclogs.com