[정보] GC 로그 포맷 - HP

HP GC 로그 포맷

GC: %1 %2 %3 %4 %5 %6 %7 %8 %9 %10 %11 %12 %13 %14 %15 %16 %17 %18 %19 %20

각 컬럼별 의미하는 바는 아래와 같다.

%1과 %2 의미	%1: 가비지 콜렉션(GC) 타입을 의미함.            1: Scavenge 또는 New 영역 GC(Minor GC)               %2: 병렬 scavenge인지 의미함                    0: non-parallel scavenge                    n(>0): parallel scavenge, n 은 병렬 GC 스레드의 수를 의미함 2: Old GC 또는 Full GC %2: Full GC 발생 이유: 1: 할당 실패, followed by a failed scavenge, leading to a Full GC 2: Call to System.gc 3: Tenured Generation full 4: Permanent Generation full 5: Scavenge followed by a Train collection 6: CMS Generation full 7: Old generation expanded on last scavenge 8: Old generation too full to scavenge 9: FullGCAlot 10: Allocation profiler triggered 3: background CMS GC 완료 %2: CMS GC 발생 이유: 1: Occupancy > initiatingOccupancy 2: Expanded recently 3: Incremental collection will fail 4: Linear allocation will fail 5: Anticipated promotion 4: background CMS GC 미완료 (exited after yielding to foreground GC) %2: n.m n indicates the GC reason: 1: Occupancy > initiatingOccupancy 2: Expanded recently 3: Incremental collection will fail 4: Linear allocation will fail 5: Anticipated promotion 6: Incremental CMS m indicates the background CMS state when yielding: 0: Resetting 1: Idling 2: InitialMarking 3: Marking 4: FinalMarking 5: Precleaning 6: Sweeping 11: CMS GC 계속
%3 의미	%3: GC 시작 시간(단위: 초) - 기동 후부터 지난 시간
%4 의미	%4: GC 발생 횟수
%5 의미	%5: GC를 유발시킨 메모리 할당 요청 크기(바이트)
%6 의미	%6: Tenuring threshold 값
%7, %8, %9 의미	The report includes the size of each space: Occupied before garbage collection (Before) Occupied after garbage collection (After) Current capacity (Capacity) All values are in bytes Eden Sub-space (within the New Generation) %7: Before %8: After %9: Capacity
%10, %11, %12 의미	Survivor Sub-space (within the New Generation) %10: Before %11: After %12: Capacity
%13, %14, %15 의미	Old Generation %13: Before %14: After %15: Capacity
%16, %17, %18 의미	Permanent Generation (Storage of Reflective Objects) %16: Before %17: After %18: Capacity
%19 의미	%19: The total stop-the-world duration, in seconds.
%20 의미	%20: The total time used in collection, in seconds.          (Concurrent 처리와 stop-the-world를 합친 시간)

HP는 JVM GC 과정을 비주얼시키기 위해 HPjtune이라는 그래픽 툴을 제공한다.

[참조] http://blog.naver.com/bumsukoh/110119881124

[참조] https://www.ibm.com/support/knowledgecenter/SS6QYM_9.2.0/com.ibm.help.perf.manage.doc/c_FND_PM_ComprehensiveHPGCLogs.html