Java Virtual Machine Tuning guide. It describes JVM Memory model and tuning guide

1. JavaStudy Network Daehyub Cho JVM [Java Virtual Machine] Performance Tuning

2. AGENDA Basic concept of JVM Tuning 1 Hotspot compiler 2 Threading Model 3 Memory Model 4

3. Basic Concept of JVM Tuning Basic concept of JVM Tuning

6. Hotspot Compiler Hotspot compiler

15. Threading Threading model

17. Solaris M:N Thread Model Java Application Java Thread JVM Solaris OS OS Kernel Solaris Thread LWP Kernel Thread

19. Solaris 1:1 Thread Model Java Application Java Thread JVM Solaris OS OS Kernel Solaris Thread LWP Kernel Thread

21. JVM Performance Test on Solaris < Solaris 8 with JVM 1.3 > See next page graph!! Architecture Cpus Threads Model %diff in throughput (against Standard Model) Sparc 30 400/2000 Standard --- Sparc 30 400/2000 LWP Synchronization 215%/800% Sparc 30 400/2000 Bound Threads -10%/-80% Sparc 30 400/2000 Alternate One-to-one 275%/900% Sparc 4 400/2000 Standard --- Sparc 4 400/2000 LWP Synchronization 30%/60% Sparc 4 400/2000 Bound Threads -5%/-45% Sparc 4 400/2000 Alternate One-to-one 30%/50% Sparc 2 400/2000 Standard --- Sparc 2 400/2000 LWP Synchronization 0%/25% Sparc 2 400/2000 Bound Threads -30%/-40% Sparc 2 400/2000 Alternate One-to-one -10%/0% Intel 4 400/2000 Standard --- Intel 4 400/2000 LWP Synchronization 25%/60% Intel 4 400/2000 Bound Threads 0%/-10% Intel 4 400/2000 Alternate One-to-one 20%/60% Intel 2 400/2000 Standard --- Intel 2 400/2000 LWP Synchronization 15%/45% Intel 2 400/2000 Bound Threads -10%/-15% Intel 2 400/2000 Alternate One-to-one 15%/35%

23. Memory Tuning Memory Model

25. Generational Garbage Collection

29. Minor GC Eden SS1 SS1 Copy live objects to Survivor area New Object Garbage Lived Object 1 st Minor GC Old Old Old

30. Minor GC 2 nd Minor GC Old Old Old New Object Garbage Lived Object

31. Minor GC OLD 3 rd Minor GC Objects moved old space when they become tenured New Object Garbage Lived Object

33. Major GC Eden SS1 SS2 Eden SS1 SS2 Mark the objects to be removed Eden SS1 SS2 Compact the objects to be removed

46. Best Pause Concurrent GC Best Throughput Parallel GC Better Pause Incremental GC(Train) Better throughput Mark-compact

50. GC Log analysis using AWK script < GC Time >

51. GC Log analysis using HPJtune ※ http://www.hp.com/products1/unix/java/java2/hpjtune/index.html

52. GC Log analysis using AWK script < GC Amount >

55. Jmeter / Threads Histogram

56. Jmeter /Threads Group Histogram

57. Example

58. Example 2004-01-08 오후 7:14 2004-01-09 오전 8 시 전후 2004-01-09 오후 7 시 전후 금요일 업무시간 2004-01-10 오전 10 시 전후 2004-01-10 오후 6 시 전후 PEAK TIME 52000~56000 sec 9 시 ~ 1 시간 가량 Before Tuned Old Area

59. Example Peak Time 시에 Old GC 시간이 4~8 sec 로 이로 인한 Hang 현상 유발이 가능함 Before Tuned GC Time

60. Example 12 일 03:38A 12 일 05:58P 13 일 07:18A 13 일 09:38P 14 일 11:58A 15 일 01:18A 15 일 03:38P 16 일 05:58A 16 일 07:18P 17 일 08:38A 17 일 10:58P Weekend Mon Office Our Tue Office Our Thur Office Our Fri Office Our After AP Tuned GC Time

61. Example 12 일 03:38A 12 일 05:58P 13 일 07:18A 13 일 09:38P 14 일 11:58A 15 일 01:18A 15 일 03:38P 16 일 05:58A 16 일 07:18P 17 일 08:38A 17 일 10:58P Weekend Mon Office Our Tue Office Our Thur Office Our Fri Office Our

62. Summary

64. More Tips More Tips

71. Thank you