Profiling for JVM (beta)

What is profiling? Why we need it? This slide tells you the reason.

1. PROFILING FOR JVM How to verify your hypothesis - @eller86
2. Agenda Process to detect the cause of performance problem What is “profiling”? Tools to profile
3. Process to detect the cause of performance problem Make hypothesis from experience and knowledge Get Servlet’s log from middle ware like Jetty Read source code, do debugging, do profiling
4. What is “profiling”? what? why? GC storm algorithm CPU Other reading code heap dump I/O Lock? Waiting other system? I/O GC Other thread dump IZQPUIFTJT WFSJpDBUJPO
5. Tools to profile jmap jstack jstat VisualVM
6. Taking heap dump $ jmap -dump:format=b,file=dump.dat [PID]
7. Taking thread dump $ jstack -l [PID] > thread-dump.txt
8. Judging the reason why JVM uses CPU heavily $ jstat -gcutil [PID] 250 7 S0 S1 E O P YGC YGCT FGC FGCT GCT 12.44 0.00 27.20 9.49 96.70 78 0.176 5 0.495 0.672 12.44 0.00 62.16 9.49 96.70 78 0.176 5 0.495 0.672 12.44 0.00 83.97 9.49 96.70 78 0.176 5 0.495 0.672 0.00 7.74 0.00 9.51 96.70 79 0.177 5 0.495 0.673 0.00 7.74 23.37 9.51 96.70 79 0.177 5 0.495 0.673 0.00 7.74 43.82 9.51 96.70 79 0.177 5 0.495 0.673 0.00 7.74 58.11 9.51 96.71 79 0.177 5 0.495 0.673 GC was fired Young generation GC was fired
9. Detecting method which costs too much time
10. Key point Hypothesis needs verification Know “normal” performance to detect “abnormal” one
11. Reference JDK tools and utilities Browsing heap dump VisualVM Diagnosis documentation @ developerWorks My gist about JVM profiling