노트의이 시리즈는 주로 기반으로 "자바 가상 머신에 대한 심층적 인 이해 : JVM은 고급 기능과 모범 사례 2 판은"독서 노트의 책이다.
컬렉션 GC 로그
다른 가비지 컬렉션은, 로그 출력 형식은 다양하지만 몇 가지 공통적 인 특징이있다. 다양한 일반적인 가비지 컬렉터 GC 로그 친숙한 필수적인 단계는 JVM 튜닝을 수행한다.
GC 분석 로그 로그는 일반적으로 사용되는, 제 수집해야 JVM 출력 로그 정보를 인쇄하기 위해 다음과 같은 파라미터가있다 :
| 매개 변수 | 설명 |
|---|---|
| -XX : + PrintGCDetails | GC 정보를 인쇄 |
| -XX : + PrintGCTimeStamps | (기준 시간의 형태) GC 출력 소인 |
| -XX : + PrintGCDateStamps | 타임 스탬프 (형태 일) GC 출력 |
| -XX : + PrintHeapAtGC | 이전과 GC 동안은 정보를 인쇄 힙 |
| -XX : + PrintTenuringDistribution | GC 동안 인쇄 생존자 정보의 대상 연령 분포 |
| -Xloggc : $ CATALINA_HOME / 로그 / gc.log | 로그 파일에 로그를 수집하는 출력 경로를 지정합니다 |
예를 들어, 나는 시작하려면 다음 매개 변수를 사용 :
-Xms28m
-Xmx28m
-XX:PermSize=14M
-XX:MaxNewSize=14m
-XX:MaxPermSize=14m
-XX:+PrintGCDetails
-XX:+PrintGCDateStamps
-Xloggc:E:/logs/gc.log가비지 수집기를 지정하려면 JVM은, 예를 들면 대응하는 매개 변수를 추가 할 필요가 -XX:+UseG1GC, -XX:+UseConcMarkSweepGC다른
-XX : + UseParallelGC 로그 분석
(-XX : + UseParallelGC) 컬렉터 병렬 + 시리얼 올드 컬렉터 조성 JDK1.8 기본 수집기, 로그는 다음과 같습니다 :
Java HotSpot(TM) 64-Bit Server VM (25.131-b11) for windows-amd64 JRE (1.8.0_131-b11), built on Mar 15 2017 01:23:53 by "java_re" with MS VC++ 10.0 (VS2010)
Memory: 4k page, physical 8303556k(2789672k free), swap 16215992k(6967912k free)
CommandLine flags: -XX:InitialHeapSize=29360128 -XX:MaxHeapSize=29360128 -XX:MaxNewSize=14680064 -XX:+PrintGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:-UseLargePagesIndividualAllocation -XX:+UseParallelGC
2018-05-08T19:23:01.815+0800: 0.574: [GC (Allocation Failure) [PSYoungGen: 11264K->1531K(12800K)] 11264K->2283K(27136K), 0.0039021 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-08T19:23:01.906+0800: 0.664: [GC (System.gc()) [PSYoungGen: 6560K->1516K(12800K)] 7311K->2625K(27136K), 0.0030390 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-08T19:23:01.908+0800: 0.667: [Full GC (System.gc()) [PSYoungGen: 1516K->0K(12800K)] [ParOldGen: 1109K->2005K(14336K)] 2625K->2005K(27136K), [Metaspace: 5955K->5955K(1056768K)], 0.0102082 secs] [Times: user=0.00 sys=0.00, real=0.01 secs]
2018-05-08T19:23:01.954+0800: 0.714: [GC (Allocation Failure) [PSYoungGen: 11263K->64K(12800K)] 13269K->2069K(27136K), 0.0005071 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-08T19:23:01.988+0800: 0.748: [GC (Allocation Failure) [PSYoungGen: 11327K->64K(12800K)] 13333K->2069K(27136K), 0.0003509 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-08T19:23:02.019+0800: 0.779: [GC (Allocation Failure) [PSYoungGen: 11328K->128K(12800K)] 13333K->2133K(27136K), 0.0003730 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-08T19:23:02.049+0800: 0.809: [GC (Allocation Failure) [PSYoungGen: 11391K->64K(9728K)] 13397K->2077K(24064K), 0.0003454 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-08T19:24:28.365+0800: 87.124: [GC (System.gc()) [PSYoungGen: 306K->32K(11264K)] 2320K->2045K(25600K), 0.0005228 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-08T19:24:28.365+0800: 87.124: [Full GC (System.gc()) [PSYoungGen: 32K->0K(11264K)] [ParOldGen: 2013K->1706K(14336K)] 2045K->1706K(25600K), [Metaspace: 6027K->6021K(1056768K)], 0.0135435 secs] [Times: user=0.05 sys=0.00, real=0.01 secs]
Heap
PSYoungGen total 11264K, used 324K [0x00000000ff200000, 0x0000000100000000, 0x0000000100000000)
eden space 8192K, 3% used [0x00000000ff200000,0x00000000ff2513a0,0x00000000ffa00000)
from space 3072K, 0% used [0x00000000ffa00000,0x00000000ffa00000,0x00000000ffd00000)
to space 3072K, 0% used [0x00000000ffd00000,0x00000000ffd00000,0x0000000100000000)
ParOldGen total 14336K, used 1706K [0x00000000fe400000, 0x00000000ff200000, 0x00000000ff200000)
object space 14336K, 11% used [0x00000000fe400000,0x00000000fe5aa8f8,0x00000000ff200000)
Metaspace used 6032K, capacity 6242K, committed 6400K, reserved 1056768K
class space used 688K, capacity 756K, committed 768K, reserved 1048576K
현재 힙 사이즈의 초기화를 인쇄하는 데 사용되는 JVM 파라미터의 세번째 라인은 최대 힙을 설정하고, 마지막으로 GC 파라미터를 출력 -XX : + UseParallelGC한다.
네 번째 줄은 가비지 컬렉션 기록, 처음으로 가비지 수집을 시작하는 것입니다. 그런 다음 GC의 발생의 원인 GC (Allocation Failure)객체 할당 실패, GC젊은 GC 영역의 새로운 세대를 대표하는 Full GC그것은 이전 시대가 포함되어 있습니다. [PSYoungGen: 11264K->1531K(12800K)]복구 영역의 크기는 11264K이다 나타냅니다 젊은 전에 복구가 1531K이고, 전체 크기는 12800K이다. 즉시 외부 브래킷 11264K->2283K(27136K)회복 11264K이다 이전에 전체 힙 사이즈를 나타내고, 힙 사이즈 2283K 힙 27136K의 전체 크기를 회수. 0.0039021 secs그것은 쓰레기 수거 시간에 사용됩니다. 알 수있는 바와 같이, 11M의 새로운 세대는 1.5M에 대해되고, 11M의 전체 힙은 GC 후에, 이전 년 0.7M에 관하여이다 2.2M에 대해됩니다.
형식은 전체 GC 로그의 여섯 번째 줄에서 다시 모습과 유사하다.
여섯 번째 행의 처음 GC도 발생한다. GC는 이유입니다 발생한 Full GC (System.gc())코드에 System.gc ()가 전체 GC를 시작하기 때문이다. [PSYoungGen: 1516K->0K(12800K)]0K 회수 전에 회수하는 새로운 세대를 대표 1516K이고, 신세대의 전체 크기는 12800K이다. [ParOldGen: 1109K->2005K(14336K)]기존의에게 전 표현을 재활용하는 것은 복구 후 1109K, 2005K, 14336K 세의 총 크기입니다. 이어서 외측 브래킷, 2625K->2005K(27136K)복구 힙 사이즈 2625K, 2005K에 앞서, 힙 27136K의 전체 크기를 회수. [Metaspace: 5955K->5955K(1056768K)]원 공간 5955K를 복구하기 전에, 5955K, 1056768K의 전체 크기를 회복했다. GC의 0.0102082 초 사용될 때.
마지막으로 로그 정보 스택을 인쇄, 차세대 11264K의 전체 크기가 324K 사용한 새로운 세대 8192K 에덴 영역 크기는 두 영역 생존자 3072K이고, 3 %이었다. 이전 년 14336K의 전체 크기는 1706K를 사용하고있다. 차원 공간은 6032K를 사용하고있다.
-XX : + UseSerialGC 로그 분석
직렬 직렬 오래 + 콜렉터 조성물 컬렉터 (-XX는 : + UseSerialGC)는 로그 다음 :
Java HotSpot(TM) 64-Bit Server VM (25.131-b11) for windows-amd64 JRE (1.8.0_131-b11), built on Mar 15 2017 01:23:53 by "java_re" with MS VC++ 10.0 (VS2010)
Memory: 4k page, physical 8303556k(2575660k free), swap 16215992k(7063788k free)
CommandLine flags: -XX:InitialHeapSize=29360128 -XX:MaxHeapSize=29360128 -XX:MaxNewSize=14680064 -XX:+PrintGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:-UseLargePagesIndividualAllocation -XX:+UseSerialGC
2018-05-08T19:31:03.644+0800: 0.676: [GC (Allocation Failure) 2018-08-08T19:31:03.644+0800: 0.676: [DefNew: 11520K->1408K(12928K), 0.0049897 secs] 11520K->2234K(27264K), 0.0051851 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-08T19:31:03.744+0800: 0.775: [Full GC (System.gc()) 2018-08-08T19:31:03.744+0800: 0.775: [Tenured: 826K->2569K(14336K), 0.0292213 secs] 7147K->2569K(27264K), [Metaspace: 5939K->5939K(1056768K)], 0.0292829 secs] [Times: user=0.02 sys=0.00, real=0.03 secs]
2018-05-08T19:31:03.811+0800: 0.843: [GC (Allocation Failure) 2018-08-08T19:31:03.811+0800: 0.843: [DefNew: 11519K->4K(12928K), 0.0009580 secs] 14088K->2573K(27264K), 0.0010026 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-08T19:31:03.878+0800: 0.909: [GC (Allocation Failure) 2018-08-08T19:31:03.878+0800: 0.909: [DefNew: 11523K->3K(12928K), 0.0003602 secs] 14092K->2572K(27264K), 0.0004109 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-08T19:31:03.935+0800: 0.967: [GC (Allocation Failure) 2018-08-08T19:31:03.935+0800: 0.967: [DefNew: 11523K->3K(12928K), 0.0004648 secs] 14092K->2572K(27264K), 0.0005109 secs] [Times: user=0.02 sys=0.00, real=0.00 secs]
2018-05-08T19:32:31.148+0800: 88.179: [Full GC (System.gc()) 2018-08-08T19:32:31.148+0800: 88.179: [Tenured: 2569K->2540K(14336K), 0.0078915 secs] 13176K->2540K(27264K), [Metaspace: 6017K->6017K(1056768K)], 0.0079582 secs] [Times: user=0.02 sys=0.00, real=0.01 secs]
Heap
def new generation total 12928K, used 458K [0x00000000fe400000, 0x00000000ff200000, 0x00000000ff200000)
eden space 11520K, 3% used [0x00000000fe400000, 0x00000000fe472838, 0x00000000fef40000)
from space 1408K, 0% used [0x00000000fef40000, 0x00000000fef40000, 0x00000000ff0a0000)
to space 1408K, 0% used [0x00000000ff0a0000, 0x00000000ff0a0000, 0x00000000ff200000)
tenured generation total 14336K, used 2540K [0x00000000ff200000, 0x0000000100000000, 0x0000000100000000)
the space 14336K, 17% used [0x00000000ff200000, 0x00000000ff47b1e8, 0x00000000ff47b200, 0x0000000100000000)
Metaspace used 6029K, capacity 6252K, committed 6400K, reserved 1056768K
class space used 691K, capacity 761K, committed 768K, reserved 1048576K
직렬 콜렉터가 거의 사용되지 않는 한, GC 로그 형식은 비슷 [GC신세대 GC의 시작, DefNew 새로운 세대를 나타낸다. GC, GC 이유 미리 신생대 복구의 크기를 발생할 것이다 시간 인쇄 크기를 회수하고, 새로운 세대의 총 크기. 재활용되기 전에 힙 크기, 복구 크기 및 전체 크기를 인쇄, GC는 시간이 많이 걸리는 인쇄 할 수 있습니다.
[Full GC십년 된 GC의 시작은, 종신 이전 시대를 나타냅니다. 의 옛 크기, 복구의 크기, 이전 시대의 전체 크기를 재활용하기 전에, GC, GC의 이유를 발생 시간을 인쇄 할 수 있습니다. 복구 인쇄 힙의 크기, 복구 크기 및 힙의 전체 크기에 이전. 요소의 공간을 인쇄하기 전에 복구 후 복구하고, 전체 크기, GC는 시간이 많이 걸리는 인쇄 할 수 있습니다.
마지막으로, 전체 스택의 사용을 인쇄 할 수 있습니다.
-XX : + UseParNewGC 로그 분석
+ Serilal 오래 ParNew 콜렉터 조성물 (-XX : + UseParNewGC) 로그는 다음과 같다 :
Java HotSpot(TM) 64-Bit Server VM (25.131-b11) for windows-amd64 JRE (1.8.0_131-b11), built on Mar 15 2017 01:23:53 by "java_re" with MS VC++ 10.0 (VS2010)
Memory: 4k page, physical 8303556k(2874368k free), swap 16215992k(9448728k free)
CommandLine flags: -XX:InitialHeapSize=29360128 -XX:MaxHeapSize=29360128 -XX:MaxNewSize=14680064 -XX:+PrintGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:-UseLargePagesIndividualAllocation -XX:+UseParNewGC
2018-05-09T20:41:34.699+0800: 4.632: [GC (Allocation Failure) 2018-08-09T08:41:34.711+0800: 4.633: [ParNew: 11520K->1408K(12928K), 0.0149096 secs] 11520K->2265K(27264K), 0.0271137 secs] [Times: user=0.08 sys=0.00, real=0.03 secs]
2018-05-09T20:41:34.886+0800: 4.808: [Full GC (System.gc()) 2018-08-09T08:41:34.886+0800: 4.808: [Tenured: 857K->2567K(14336K), 0.0091055 secs] 6992K->2567K(27264K), [Metaspace: 5940K->5940K(1056768K)], 0.0091703 secs] [Times: user=0.02 sys=0.00, real=0.01 secs]
2018-05-09T20:41:34.964+0800: 4.887: [GC (Allocation Failure) 2018-08-09T08:41:34.964+0800: 4.887: [ParNew: 11519K->1214K(12928K), 0.0132311 secs] 14086K->3781K(27264K), 0.0132796 secs] [Times: user=0.00 sys=0.00, real=0.01 secs]
2018-05-09T20:41:35.024+0800: 4.946: [GC (Allocation Failure) 2018-08-09T08:41:35.024+0800: 4.946: [ParNew: 12734K->151K(12928K), 0.0004635 secs] 15301K->2719K(27264K), 0.0005408 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-09T20:41:35.057+0800: 4.979: [GC (Allocation Failure) 2018-08-09T08:41:35.057+0800: 4.979: [ParNew: 11671K->38K(12928K), 0.0003371 secs] 14239K->2605K(27264K), 0.0003801 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-09T20:42:59.030+0800: 88.953: [Full GC (System.gc()) 2018-08-09T08:42:59.030+0800: 88.953: [Tenured: 2567K->2536K(14336K), 0.0086218 secs] 13341K->2536K(27264K), [Metaspace: 6012K->6012K(1056768K)], 0.0086850 secs] [Times: user=0.02 sys=0.00, real=0.01 secs]
Heap
par new generation total 12928K, used 227K [0x00000000fe400000, 0x00000000ff200000, 0x00000000ff200000)
eden space 11520K, 1% used [0x00000000fe400000, 0x00000000fe438f88, 0x00000000fef40000)
from space 1408K, 0% used [0x00000000fef40000, 0x00000000fef40000, 0x00000000ff0a0000)
to space 1408K, 0% used [0x00000000ff0a0000, 0x00000000ff0a0000, 0x00000000ff200000)
tenured generation total 14336K, used 2536K [0x00000000ff200000, 0x0000000100000000, 0x0000000100000000)
the space 14336K, 17% used [0x00000000ff200000, 0x00000000ff47a1e8, 0x00000000ff47a200, 0x0000000100000000)
Metaspace used 6023K, capacity 6252K, committed 6400K, reserved 1056768K
class space used 691K, capacity 761K, committed 768K, reserved 1048576K
다음은 컬렉터 GC 로그 ParNew + Serilal 올드 조합과 비슷한 형식입니다.
-XX : + UseParallelOldGC 로그 분석
병렬 집 집 + 병렬 오래 조성물 (-XX : + UseParallelOldGC) 로그는 다음과 같다 :
Java HotSpot(TM) 64-Bit Server VM (25.131-b11) for windows-amd64 JRE (1.8.0_131-b11), built on Mar 15 2017 01:23:53 by "java_re" with MS VC++ 10.0 (VS2010)
Memory: 4k page, physical 8303556k(2759076k free), swap 16215992k(7616208k free)
CommandLine flags: -XX:InitialHeapSize=29360128 -XX:MaxHeapSize=29360128 -XX:MaxNewSize=14680064 -XX:+PrintGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:-UseLargePagesIndividualAllocation -XX:+UseParallelOldGC
2018-05-09T20:44:49.341+0800: 0.618: [GC (Allocation Failure) [PSYoungGen: 11264K->1531K(12800K)] 11264K->2274K(27136K), 0.0043755 secs] [Times: user=0.05 sys=0.00, real=0.00 secs]
2018-05-09T20:44:49.478+0800: 0.754: [GC (System.gc()) [PSYoungGen: 6544K->1531K(12800K)] 7286K->2626K(27136K), 0.0064927 secs] [Times: user=0.00 sys=0.00, real=0.01 secs]
2018-05-09T20:44:49.484+0800: 0.761: [Full GC (System.gc()) [PSYoungGen: 1531K->0K(12800K)] [ParOldGen: 1094K->1917K(14336K)] 2626K->1917K(27136K), [Metaspace: 5968K->5968K(1056768K)], 0.0125897 secs] [Times: user=0.03 sys=0.00, real=0.01 secs]
2018-05-09T20:44:49.624+0800: 0.901: [GC (Allocation Failure) [PSYoungGen: 11263K->64K(12800K)] 13181K->1981K(27136K), 0.0227273 secs] [Times: user=0.00 sys=0.00, real=0.02 secs]
2018-05-09T20:44:49.690+0800: 0.967: [GC (Allocation Failure) [PSYoungGen: 11327K->64K(12800K)] 13245K->1981K(27136K), 0.0004702 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-09T20:44:49.729+0800: 1.007: [GC (Allocation Failure) [PSYoungGen: 11328K->64K(12800K)] 13245K->1981K(27136K), 0.0080092 secs] [Times: user=0.00 sys=0.00, real=0.01 secs]
2018-05-09T20:44:49.774+0800: 1.052: [GC (Allocation Failure) [PSYoungGen: 11327K->64K(9728K)] 13245K->1989K(24064K), 0.0019594 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-09T20:46:15.771+0800: 87.048: [GC (System.gc()) [PSYoungGen: 302K->64K(11264K)] 2227K->1989K(25600K), 0.0004195 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-09T20:46:15.771+0800: 87.048: [Full GC (System.gc()) [PSYoungGen: 64K->0K(11264K)] [ParOldGen: 1925K->1704K(14336K)] 1989K->1704K(25600K), [Metaspace: 6039K->6033K(1056768K)], 0.0126567 secs] [Times: user=0.05 sys=0.00, real=0.01 secs]
Heap
PSYoungGen total 11264K, used 324K [0x00000000ff200000, 0x0000000100000000, 0x0000000100000000)
eden space 8192K, 3% used [0x00000000ff200000,0x00000000ff2513a0,0x00000000ffa00000)
from space 3072K, 0% used [0x00000000ffa00000,0x00000000ffa00000,0x00000000ffd00000)
to space 3072K, 0% used [0x00000000ffd00000,0x00000000ffd00000,0x0000000100000000)
ParOldGen total 14336K, used 1704K [0x00000000fe400000, 0x00000000ff200000, 0x00000000ff200000)
object space 14336K, 11% used [0x00000000fe400000,0x00000000fe5aa360,0x00000000ff200000)
Metaspace used 6044K, capacity 6242K, committed 6400K, reserved 1056768K
class space used 688K, capacity 756K, committed 768K, reserved 1048576K
이러한 병렬 컬렉터 + GC 로그의 병렬 올드 수집 조합, JDK1.8와 기본 형식입니다 -XX:+UseParallelGC이하 동일.
-XX : + UseConcMarkSweepGC 로그 분석
-XX : ConcurrentMode 페일 추진이 실패했을 경우는 CMS UseConcMarkSweepGC + + ParNew 콜렉터 콜렉터 콜렉터 바람직 조합 ParNew + 콜렉터 CMS 컬렉터에 사용 + 직렬 오래 조성물, 또는 상기 콜렉터 ParNew + 직렬 오래 사용 지정할 콜렉터 조합. 다음과 같이 로그는 다음과 같습니다
Java HotSpot(TM) 64-Bit Server VM (25.131-b11) for windows-amd64 JRE (1.8.0_131-b11), built on Mar 15 2017 01:23:53 by "java_re" with MS VC++ 10.0 (VS2010)
Memory: 4k page, physical 8303556k(2846816k free), swap 16215992k(7664596k free)
CommandLine flags: -XX:InitialHeapSize=29360128 -XX:MaxHeapSize=29360128 -XX:MaxNewSize=14680064 -XX:MaxTenuringThreshold=6 -XX:OldPLABSize=16 -XX:+PrintGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseConcMarkSweepGC -XX:-UseLargePagesIndividualAllocation -XX:+UseParNewGC
2018-05-09T20:53:14.086+0800: 0.590: [GC (Allocation Failure) 2018-08-09T11:53:14.086+0800: 0.590: [ParNew: 11520K->1407K(12928K), 0.0034803 secs] 11520K->2254K(27264K), 0.0039082 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-09T20:53:14.247+0800: 0.751: [Full GC (System.gc()) 2018-08-09T11:53:14.247+0800: 0.751: [CMS: 846K->1930K(14336K), 0.0103698 secs] 7165K->1930K(27264K), [Metaspace: 5963K->5963K(1056768K)], 0.0104529 secs] [Times: user=0.02 sys=0.00, real=0.01 secs]
2018-05-09T20:53:14.292+0800: 0.795: [GC (Allocation Failure) 2018-08-09T11:53:14.292+0800: 0.795: [ParNew: 11519K->1199K(12928K), 0.0085679 secs] 13450K->3129K(27264K), 0.0086244 secs] [Times: user=0.00 sys=0.00, real=0.01 secs]
2018-05-09T20:53:14.333+0800: 0.836: [GC (Allocation Failure) 2018-08-09T11:53:14.333+0800: 0.836: [ParNew: 12719K->300K(12928K), 0.0002620 secs] 14649K->2230K(27264K), 0.0003041 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-09T20:53:14.364+0800: 0.867: [GC (Allocation Failure) 2018-08-09T11:53:14.364+0800: 0.867: [ParNew: 11820K->75K(12928K), 0.0002787 secs] 13750K->2005K(27264K), 0.0003223 secs] [Times: user=0.00 sys=0.00, real=0.00 secs]
# 并发标记周期开始，根区域扫描
2018-05-09T20:59:47.982+0800: 9.634: [GC concurrent-root-region-scan-start]
2018-05-09T20:59:47.982+0800: 9.652: [GC concurrent-root-region-scan-end, 0.0184308 secs]
# 并发标记
2018-05-09T20:59:47.982+0800: 9.652: [GC concurrent-mark-start]
2018-05-09T20:59:47.982+0800: 9.693: [GC concurrent-mark-end, 0.0406187 secs]
# 重新标记
2018-05-09T20:59:47.982+0800: 9.695: [GC remark 9.695: [Finalize Marking, 0.0005100 secs] 9.695: [GC ref-proc, 0.0003461 secs] 9.696: [Unloading, 0.0069466 secs], 0.0082011 secs]
[Times: user=0.02 sys=0.00, real=0.01 secs]
# 独占清理
2018-05-09T20:59:47.982+0800: 9.703: [GC cleanup 25M->21M(1024M), 0.0027119 secs]
[Times: user=0.00 sys=0.01, real=0.00 secs]
# 并发清理
2018-05-09T20:59:47.982+0800: 9.706: [GC concurrent-cleanup-start]
2018-05-09T20:59:47.982+0800: 9.706: [GC concurrent-cleanup-end, 0.0000167 secs]
2018-05-09T20:54:39.299+0800: 85.803: [Full GC (System.gc()) 2018-08-09T11:54:39.299+0800: 85.803: [CMS: 1930K->1832K(14336K), 0.0089015 secs] 12748K->1832K(27264K), [Metaspace: 6035K->6035K(1056768K)], 0.0089724 secs] [Times: user=0.00 sys=0.00, real=0.01 secs]
Heap
par new generation total 12928K, used 227K [0x00000000fe400000, 0x00000000ff200000, 0x00000000ff200000)
eden space 11520K, 1% used [0x00000000fe400000, 0x00000000fe438cd8, 0x00000000fef40000)
from space 1408K, 0% used [0x00000000fef40000, 0x00000000fef40000, 0x00000000ff0a0000)
to space 1408K, 0% used [0x00000000ff0a0000, 0x00000000ff0a0000, 0x00000000ff200000)
concurrent mark-sweep generation total 14336K, used 1832K [0x00000000ff200000, 0x0000000100000000, 0x0000000100000000)
Metaspace used 6045K, capacity 6252K, committed 6400K, reserved 1056768K
class space used 691K, capacity 761K, committed 768K, reserved 1048576K
현재 인쇄하는 데 사용되는 JVM 매개 변수의 세 번째 줄 -XX:MaxTenuringThreshold=6객체가 6 세의 대상 연령에 새로운 세대의 필요에 이전부터 추진되었다 수단, 그 후 6 GC.
네번째 줄은 영 GC 면적의 새로운 세대, 처음 GC가 발생했습니다. 이어서 GC의 발생 원인은 GC (Allocation Failure), 오브젝트 할당 실패. [ParNew: 11520K->1407K(12928K), 0.0034803 secs]복구가 12928K의 전체 크기의 새로운 세대, 회복이 0.0034803 초를했다, 1407K 후 회복이, 11520K되기 전에 새로운 세대를 나타냅니다. 11520K->2254K(27264K), 0.0039082 secs11520K 회복 전의 힙 사이즈는, 힙 사이즈 2254K, 27264K 힙의 전체 크기 회수.
다섯 번째 줄은 GC가 발생 GC 올드 지역의 오래된, 이번이 처음이다. GC는 발생 이유 System.gc()코드가 호출되기 때문에. [CMS: 846K->1930K(14336K), 0.0103698 secs]기존의 재활용 전 대표는 1930K의 복구 후, 이전 년 14336K의 전체 크기는 복구 0.0103698 초를했다, 846K이었다. 7165K->1930K(27264K)7165K 힙 크기가 복구 이전에, 힙 크기 1930K, 27264K의 힙의 전체 크기를 회복 나타냅니다.
동시 마크주기 뒤에 파라미터 설정하면 -XX:InitiatingHeapOccupancyPercent값을 동시에 표시를 트리거 할 때, 당신은 힙의 몇 퍼센트 점유율을 지정할 수 있습니다, 기본값은 45 %입니다.
마지막으로, 새로운 세대, 옛날, 위안의 공간으로, 사용의 전체 힙을 인쇄 할 수 있습니다.
-XX : + UseG1GC 로그 분석
(-XX : + UseG1GC) G1 병렬 메모리 리콜 동시에 기본 JDK1.9 수집기 지정 G1 수집기, 그것은 매우 다양한 형식이 로그는 다음과 같다 :
Java HotSpot(TM) 64-Bit Server VM (25.131-b11) for windows-amd64 JRE (1.8.0_131-b11), built on Mar 15 2017 01:23:53 by "java_re" with MS VC++ 10.0 (VS2010)
Memory: 4k page, physical 8303556k(2436164k free), swap 16215992k(7422076k free)
CommandLine flags: -XX:InitialHeapSize=29360128 -XX:MaxHeapSize=29360128 -XX:MaxNewSize=14680064 -XX:+PrintGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseG1GC -XX:-UseLargePagesIndividualAllocation
# 新生代GC，young区，暂停0.0022375秒
2018-05-09T20:59:47.639+0800: 0.484: [GC pause (G1 Evacuation Pause) (young), 0.0022375 secs]
# 并行时间1.7ms，4个GC线程
[Parallel Time: 1.7 ms, GC Workers: 4]
# 开始时刻，相对开始时间点，4个线程的最小值、平均值、最大值
[GC Worker Start (ms): Min: 484.4, Avg: 484.4, Max: 484.5, Diff: 0.0]
# 根节点扫描耗时
[Ext Root Scanning (ms): Min: 0.4, Avg: 0.7, Max: 1.6, Diff: 1.2, Sum: 2.7]
# 更新记忆集（RS, Remembered Set）耗时G1中每块区域都有一个RS与之对应，RS记录了该区域被其他区域引用的对象。回收时，就把RS作为根集的一部分，从而加快回收。
[Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
# Processed Buffers就是记录引用变化的缓存空间
[Processed Buffers: Min: 0, Avg: 0.0, Max: 0, Diff: 0, Sum: 0]
# 扫描RS耗时
[Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
# 根扫描耗时
[Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.1]
# 对象拷贝（疏散回收的区域）
[Object Copy (ms): Min: 0.0, Avg: 0.8, Max: 1.1, Diff: 1.1, Sum: 3.3]
# 线程在终止阶段的耗时，线程在终止前，会检查其他线程的队列，看是否有未清理完的Reference。如有则帮助其他线程清理，之后再尝试终止
[Termination (ms): Min: 0.0, Avg: 0.1, Max: 0.1, Diff: 0.1, Sum: 0.3]
# 尝试终止次数
[Termination Attempts: Min: 1, Avg: 1.8, Max: 2, Diff: 1, Sum: 7]
# GC线程花在其他任务中的耗时
[GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
# GC线程耗时
[GC Worker Total (ms): Min: 1.6, Avg: 1.6, Max: 1.6, Diff: 0.0, Sum: 6.5]
# 完成时刻
[GC Worker End (ms): Min: 486.1, Avg: 486.1, Max: 486.1, Diff: 0.0]
[Code Root Fixup: 0.0 ms]
[Code Root Purge: 0.0 ms]
# 清空CardTable耗时，RS是依赖CardTable记录区域存活对象的
[Clear CT: 0.0 ms]
# 其他任务耗时
[Other: 0.5 ms]
# 选取将要被回收的区域的集合耗时
[Choose CSet: 0.0 ms]
# 弱引用、软引用的处理耗时
[Ref Proc: 0.4 ms]
# 弱引用、软引用的入队耗时
[Ref Enq: 0.0 ms]
[Redirty Cards: 0.0 ms]
[Humongous Register: 0.0 ms]
[Humongous Reclaim: 0.0 ms]
# 释放被回收区域的耗时（包含他们的RS）
[Free CSet: 0.0 ms]
# Eden区、Survivor区、堆的回收前大小、回收后大小、以及总大小
[Eden: 5120.0K(5120.0K)->0.0B(11.0M) Survivors: 0.0B->1024.0K Heap: 5120.0K(28.0M)->1631.5K(28.0M)]
[Times: user=0.00 sys=0.00, real=0.00 secs]
# 并发标记周期开始，根区域扫描
2018-05-09T20:59:47.982+0800: 9.634: [GC concurrent-root-region-scan-start]
2018-05-09T20:59:47.982+0800: 9.652: [GC concurrent-root-region-scan-end, 0.0184308 secs]
# 并发标记
2018-05-09T20:59:47.982+0800: 9.652: [GC concurrent-mark-start]
2018-05-09T20:59:47.982+0800: 9.693: [GC concurrent-mark-end, 0.0406187 secs]
# 重新标记
2018-05-09T20:59:47.982+0800: 9.695: [GC remark 9.695: [Finalize Marking, 0.0005100 secs] 9.695: [GC ref-proc, 0.0003461 secs] 9.696: [Unloading, 0.0069466 secs], 0.0082011 secs]
[Times: user=0.02 sys=0.00, real=0.01 secs]
# 独占清理
2018-05-09T20:59:47.982+0800: 9.703: [GC cleanup 25M->21M(1024M), 0.0027119 secs]
[Times: user=0.00 sys=0.01, real=0.00 secs]
# 并发清理
2018-05-09T20:59:47.982+0800: 9.706: [GC concurrent-cleanup-start]
2018-05-09T20:59:47.982+0800: 9.706: [GC concurrent-cleanup-end, 0.0000167 secs]
# 下一轮回收，FullGC，堆的回收前、回收后、以及总大小。Eden、Survivor、元空间的大小。
2018-05-09T20:59:47.982+0800: 0.828: [Full GC (System.gc()) 12M->2223K(28M), 0.0128065 secs]
[Eden: 11.0M(11.0M)->0.0B(12.0M) Survivors: 1024.0K->0.0B Heap: 12.2M(28.0M)->2223.0K(28.0M)], [Metaspace: 5951K->5951K(1056768K)]
[Times: user=0.02 sys=0.00, real=0.01 secs]
# 新生代GC
2018-05-09T20:59:48.040+0800: 0.886: [GC pause (G1 Evacuation Pause) (young), 0.0005693 secs]
[Parallel Time: 0.4 ms, GC Workers: 4]
[GC Worker Start (ms): Min: 886.1, Avg: 886.1, Max: 886.1, Diff: 0.0]
[Ext Root Scanning (ms): Min: 0.2, Avg: 0.2, Max: 0.2, Diff: 0.0, Sum: 0.8]
[Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.2]
[Processed Buffers: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 4]
[Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
[Termination (ms): Min: 0.0, Avg: 0.1, Max: 0.1, Diff: 0.1, Sum: 0.3]
[Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 4]
[GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[GC Worker Total (ms): Min: 0.3, Avg: 0.3, Max: 0.4, Diff: 0.0, Sum: 1.4]
[GC Worker End (ms): Min: 886.5, Avg: 886.5, Max: 886.5, Diff: 0.0]
[Code Root Fixup: 0.0 ms]
[Code Root Purge: 0.0 ms]
[Clear CT: 0.0 ms]
[Other: 0.1 ms]
[Choose CSet: 0.0 ms]
[Ref Proc: 0.0 ms]
[Ref Enq: 0.0 ms]
[Redirty Cards: 0.0 ms]
[Humongous Register: 0.0 ms]
[Humongous Reclaim: 0.0 ms]
[Free CSet: 0.0 ms]
[Eden: 12.0M(12.0M)->0.0B(12.0M) Survivors: 0.0B->2048.0K Heap: 14.2M(28.0M)->3460.3K(28.0M)]
[Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-09T20:59:48.103+0800: 0.949: [GC pause (G1 Evacuation Pause) (young), 0.0004664 secs]
[Parallel Time: 0.3 ms, GC Workers: 4]
[GC Worker Start (ms): Min: 949.2, Avg: 949.3, Max: 949.5, Diff: 0.3]
[Ext Root Scanning (ms): Min: 0.0, Avg: 0.2, Max: 0.2, Diff: 0.2, Sum: 0.6]
[Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Processed Buffers: Min: 0, Avg: 1.0, Max: 2, Diff: 2, Sum: 4]
[Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
[Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 4]
[GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[GC Worker Total (ms): Min: 0.0, Avg: 0.2, Max: 0.3, Diff: 0.3, Sum: 0.8]
[GC Worker End (ms): Min: 949.5, Avg: 949.5, Max: 949.5, Diff: 0.0]
[Code Root Fixup: 0.0 ms]
[Code Root Purge: 0.0 ms]
[Clear CT: 0.0 ms]
[Other: 0.1 ms]
[Choose CSet: 0.0 ms]
[Ref Proc: 0.1 ms]
[Ref Enq: 0.0 ms]
[Redirty Cards: 0.0 ms]
[Humongous Register: 0.0 ms]
[Humongous Reclaim: 0.0 ms]
[Free CSet: 0.0 ms]
[Eden: 12.0M(12.0M)->0.0B(13.0M) Survivors: 2048.0K->1024.0K Heap: 15.4M(28.0M)->2383.6K(28.0M)]
[Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-09T20:59:48.146+0800: 0.992: [GC pause (G1 Evacuation Pause) (young), 0.0004067 secs]
[Parallel Time: 0.3 ms, GC Workers: 4]
[GC Worker Start (ms): Min: 991.9, Avg: 991.9, Max: 991.9, Diff: 0.0]
[Ext Root Scanning (ms): Min: 0.2, Avg: 0.2, Max: 0.2, Diff: 0.0, Sum: 0.8]
[Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Processed Buffers: Min: 1, Avg: 1.3, Max: 2, Diff: 1, Sum: 5]
[Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 4]
[GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
[GC Worker Total (ms): Min: 0.2, Avg: 0.2, Max: 0.2, Diff: 0.0, Sum: 0.9]
[GC Worker End (ms): Min: 992.2, Avg: 992.2, Max: 992.2, Diff: 0.0]
[Code Root Fixup: 0.0 ms]
[Code Root Purge: 0.0 ms]
[Clear CT: 0.0 ms]
[Other: 0.1 ms]
[Choose CSet: 0.0 ms]
[Ref Proc: 0.0 ms]
[Ref Enq: 0.0 ms]
[Redirty Cards: 0.0 ms]
[Humongous Register: 0.0 ms]
[Humongous Reclaim: 0.0 ms]
[Free CSet: 0.0 ms]
[Eden: 13.0M(13.0M)->0.0B(13.0M) Survivors: 1024.0K->1024.0K Heap: 15.3M(28.0M)->2277.1K(28.0M)]
[Times: user=0.00 sys=0.00, real=0.00 secs]
2018-05-09T21:01:18.300+0800: 91.146: [Full GC (System.gc()) 9971K->1815K(28M), 0.0099218 secs]
[Eden: 8192.0K(13.0M)->0.0B(14.0M) Survivors: 1024.0K->0.0B Heap: 9971.7K(28.0M)->1815.8K(28.0M)], [Metaspace: 6026K->6026K(1056768K)]
[Times: user=0.00 sys=0.00, real=0.01 secs]
Heap
garbage-first heap total 28672K, used 1815K [0x00000000fe400000, 0x00000000fe5000e0, 0x0000000100000000)
region size 1024K, 1 young (1024K), 0 survivors (0K)
Metaspace used 6038K, capacity 6252K, committed 6400K, reserved 1056768K
class space used 691K, capacity 761K, committed 768K, reserved 1048576K
G1日志分析详见上面代码中的注释 상기 G1 컬렉터보다 가비지 컬렉션 전에 약간 더 복잡.