JJUG JavaOne 2012 San Francisco 報告会, LT - G1GC のスライドです。 This Presentation Slide is the LT about G1GC at JJUG JavaOne 2012 San Francisco Briefing Meeting(Tokyo/Japan), 2012/11/9, Gree Inc.

1. JJUG JavaOne 2012 San Francisco 報告会
(LT) G1GC チューニング
と G1GC Visualizer
～ CON6583 – G1 Garbage Collector Performance Tuning より ～
2012/11/9
木村英一(@kimuchi583)
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 1

2. 木村 英一 って、誰 ?
武蔵小杉駅 横須賀線口の前に立つビルで
Java案件支援, チューニング 諸々に対応してます。
Twitter : @kimuchi583
URL : http://kimuchi583.at.webry.info/
http://blog.kimu2.jp/
本セッションの内容は、
http://www.myexpospace.com/JavaOne2012/SessionFiles/CON658
3_PDF_6583_0001.pdf
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 2

3. オプションは、これだけ !!
‐Xms6g
‐Xmx6g
‐XX:+UseG1GC
‐XX:MaxGCPauseMillis=200
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 3

4. これらのオプションはダメ !!
‐Xmn
‐XX:MaxNewSize
‐XX:NewSize
‐XX:NewRatio
‐XX:SurvivorRatio
Young 領域は目標達成のために自動的に調整される
(ヒープ全体の20%～80%の範囲で)
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 4

5. Young 領域サイズを指定をすると …
Young 領域のサイズを自動調整しない
一時停止時間の目標設定は無視する
私のほうが Java VM より
上手くチューニングできる
!! 宣言 !!
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 5

6. G1GC の動作状況を分析するには
ログ出力用
[‐verbosegc | ‐XLoggc:<gc.log>]
‐XX:+PrintGC
‐XX:+PrintGCTimeStamps
‐XX:+PrintGCDateStamps
‐XX:+PrintGCDetails
‐XX:+PrintAdaptiveSizePolicy
‐XX:+UnlockExperimentalVMOptions –XX:G1LogLevel=[fine | finer | finest]
チューニング用
‐XX:InitiatingHeapOccupancyPercent=<percent>
‐XX:G1OldCSetRegionLiveThresholdPercent=<percent>
‐XX:G1MixedGCCountTarget=<N>
‐XX:G1HeapWastePercent=<N>
(http://www.oracle.com/technetwork/java/javase/tech/vmoptions-jsp-140102.html)
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 6

7. でも使えるのは、これだけ
ログ出力用
[‐verbosegc | ‐XLoggc:<gc.log>]
‐XX:+PrintGC
‐XX:+PrintGCTimeStamps
‐XX:+PrintGCDateStamps
‐XX:+PrintGCDetails
‐XX:+PrintAdaptiveSizePolicy
‐XX:+UnlockExperimentalVMOptions –XX:G1LogLevel=[fine | finer | finest]
チューニング用
‐XX:InitiatingHeapOccupancyPercent=<percent>
‐XX:G1OldCSetRegionLiveThresholdPercent=<percent>
‐XX:G1MixedGCCountTarget=<N>
‐XX:G1HeapWastePercent=<N>
(http://www.oracle.com/technetwork/java/javase/tech/vmoptions-jsp-140102.html)
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 7

8. G1GC のサイクル
Initial Mark – STW
Root Region Scanning – Concurrent
Concurrent Marking – Concurrent
Remark – STW
Cleanup – STW + Concurrent
Copying(Young GC/Mixed GC) - STW 8
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9

9. Mark Phase Copy phase
Young mode
Mark /Remark Phase Cleanup Phase Copy Phase
高 高 高 高 高 高
高 高 高
Mixed mode
高 高 高 高 高 高
高 低 高 低 高
高 高 低 低 高 高 低 低 高 高
高 低 高 低 高 低
Non-Allocated Eden Survivor Old
Recently copied in Survivor Recently copied in Old
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 9

10. こんな GC ログ、読むのは大変
{Heap before GC invocations=0 (full 0):
garbage-first heap total 16384K, used 5120K [0x03600000, 0x04600000, 0x05a00000)
region size 1024K, 5 young (5120K), 0 survivors (0K)
compacting perm gen total 12288K, used 6053K [0x05a00000, 0x06600000, 0x09a00000)
the space 12288K, 49% used [0x05a00000, 0x05fe9478, 0x05fe9600, 0x06600000)
No shared spaces configured.
2012-08-22T16:37:32.445+0900: G1HR #StartGC 1
0.911: [GC pause (young)
Desired survivor size 524288 bytes, new threshold 15 (max 15)
0.911: [G1Ergonomics (CSet Construction) start choosing CSet, predicted base time: 83.70 ms, remaining time: 116.30 ms, target pause time: 200.00 ms]
0.911: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 5 regions, survivors: 0 regions, predicted young region time: 127.33 ms]
0.911: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 5 regions, survivors: 0 regions, old: 0 regions, predicted pause time: 211.03 ms, target
pause time: 200.00 ms]
G1HR CSET 0x03a00000
:
G1HR ALLOC(Survivor) 0x03b00000
G1HR ALLOC(Old) 0x03c00000
G1HR RETIRE 0x03c00000 0x03ccee20, 0.01186911 secs]
[Parallel Time: 11.0 ms]
[GC Worker Start (ms): 911.1 911.1 911.1 911.1 Avg: 911.1, Min: 911.1, Max: 911.1, Diff: 0.0]
[Ext Root Scanning (ms): 2.6 3.5 3.6 4.6 Avg: 3.6, Min: 2.6, Max: 4.6, Diff: 2.0]
[Update RS (ms): 0.0 0.1 0.0 0.0 Avg: 0.0, Min: 0.0, Max: 0.1, Diff: 0.1]
[Processed Buffers : 0 14 0 0 Sum: 14, Avg: 3, Min: 0, Max: 14, Diff: 14]
[Scan RS (ms): 0.0 0.0 0.0 0.0 Avg: 0.0, Min: 0.0, Max: 0.0, Diff: 0.0]
[Object Copy (ms): 8.2 7.0 7.0 6.0 Avg: 7.1, Min: 6.0, Max: 8.2, Diff: 2.2]
[Termination (ms): 0.0 0.0 0.0 0.0 Avg: 0.0, Min: 0.0, Max: 0.0, Diff: 0.0]
[Termination Attempts : 2 2 1 1 Sum: 6, Avg: 1, Min: 1, Max: 2, Diff: 1]
[GC Worker End (ms): 921.9 921.9 921.9 921.9 Avg: 921.9, Min: 921.9, Max: 921.9, Diff: 0.0]
[GC Worker (ms): 10.9 10.9 10.9 10.8 Avg: 10.9, Min: 10.8, Max: 10.9, Diff: 0.0]
[GC Worker Other (ms): 0.2 0.3 0.3 0.3 Avg: 0.3, Min: 0.2, Max: 0.3, Diff: 0.2]
[Clear CT: 0.1 ms]
[Other: 0.7 ms]
[Choose CSet: 0.0 ms]
[Ref Proc: 0.5 ms]
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 10

11. そこで – JavaOne 2012 になかったネタ
G1GC ログの可視化したい
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 11

12. 本セッションの内容は、
Fin.
http://www.myexpospace.com/JavaOne2012/SessionFiles/CON6583_PDF_65
83_0001.pdf
© 2012 EIICHI KIMURA All Rights Reserved. 2012/11/9 12