Upload - GC Log Analyzer

Before you upload

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 stats are not accurate).
Max 33MB file (after compression).
For JDK 11+ decorators: level, tags, time, uptime are needed. Check sample Xlog configuration below.
You can add many log files in one zip/7z archive. Files will be ordered by first line timestamp.

Upload File

Upload from Clipboard

Upload with cURL

Compress your logs:

zip -r logs.zip logs_file.log*

Make sure your logs are not bigger than 33MB after compression.

Upload logs archive to the server:

curl -X POST --form file=@./logs.zip http://gclogs.com/enqueue

In response you'll receive a link to your report. The report will be available for 3 minutes.

Kubernetes

kubectl exec -t <pod> -- curl -X POST --form file=@<path> http://gclogs.com/enqueue

The curl command must be available in the container.

Recommended JVM Arguments

VM Args that I use

-Xlog:codecache=info,
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

Unified logger — changing logs at runtime

sudo -u JVM_USER jcmd `pgrep -x java` VM.log
output="file=/PATH/TO/gc.log"
output_options="filesize=104857600,filecount=5"
what="codecache=info,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

Safepoint & GC Log Analyzer

Before you upload

Kubernetes

Terms of service