java9 gc log參數(shù)遷移

Kahn 發(fā)布于2019-08-15 14:30 / 3531人閱讀

摘要：序本文主要研究一下參數(shù)的遷移。比如實例為，為，文件數(shù)為，每個文件，文件名為，為和輸出實例遷移舊版相關參數(shù)遷移舊版運行時參數(shù)遷移小結把的配置統(tǒng)一到了中，可以按照官方給出的新舊參數(shù)映射表進行遷移。

序

本文主要研究一下java9 gc log參數(shù)的遷移。

統(tǒng)一JVM及GC的Logging

java9引進了一個統(tǒng)一的日志框架，對gc log的輸出進行了統(tǒng)一的配置。

相關JEP(JDK Enhancement Proposal)

JEP 158: Unified JVM Logging

JEP 264: Platform Logging API and Service

JEP 271: Unified GC Logging

Xlog語法

-Xlog[:option]
    option         :=  [][:[][:[][:]]]
                       "help"
                       "disable"
    what           :=  [,...]
    selector       :=  [*][=]
    tag-set        :=  [+...]
                       "all"
    tag            :=  name of tag
    level          :=  trace
                       debug
                       info
                       warning
                       error
    output         :=  "stderr"
                       "stdout"
                       [file=]
    decorators     :=  [,...]
                       "none"
    decorator      :=  time
                       uptime
                       timemillis
                       uptimemillis
                       timenanos
                       uptimenanos
                       pid
                       tid
                       level
                       tags
    output-options :=  [,...]
    output-option  :=  filecount=
                       filesize=
                       parameter=value

what

主要是配置tag及l(fā)evel

tag

其中all代表所有的tag，其他的如下：

add，age，alloc，annotation，aot，arguments，attach，barrier，biasedlocking，blocks，bot，breakpoint，bytecode，census，class，classhisto，cleanup，compaction，comparator，constraints，constantpool，coops，cpu，cset，data，defaultmethods，dump，ergo，event，exceptions，exit，fingerprint，freelist，gc，hashtables，heap，humongous，ihop，iklass，init，itables，jfr，jni，jvmti，liveness，load，loader，logging，mark，marking，metadata，metaspace，method，mmu，modules，monitorinflation，monitormismatch，nmethod，normalize，objecttagging，obsolete，oopmap，os，pagesize，parser，patch，path，phases，plab，preorder，promotion，protectiondomain，purge，redefine，ref，refine，region，remset，resolve，safepoint，scavenge，scrub，setting，stackmap，stacktrace，stackwalk，start，startuptime，state，stats，stringdedup，stringtable，subclass，survivor，sweep，system，task，thread，time，timer，tlab，unload，update，verification，verify，vmoperation，vtables，workgang

level

主要分off，trace，debug，info，warning，error

output

- stdout(`Sends output to stdout`)
- stderr(`Sends output to stderr`)
- file=filename(`Sends output to text file(s)`)

有如上三種，其中指定file的話，可以使用%p變量表示當前jvm的pid，用%t表示jvm的啟動時間戳。比如

-Xlog:gc:demoapp-gc-%p-%t.log

輸出的文件名如下：

demoapp-gc-1678-2018-03-01_21-44-18.log

decorators

time -- Current time and date in ISO-8601 format

uptime -- Time since the start of the JVM in seconds and milliseconds (e.g., 6.567s)

timemillis -- The same value as generated by System.currentTimeMillis()

uptimemillis -- Milliseconds since the JVM started

timenanos -- The same value as generated by System.nanoTime()

uptimenanos -- Nanoseconds since the JVM started

pid -- The process identifier

tid -- The thread identifier

level -- The level associated with the log message

tags -- The tag-set associated with the log message

不指定的話，默認是uptime, level, and tags這三個。比如

[3.080s][info][gc,cpu        ] GC(5) User=0.03s Sys=0.00s Real=0.01s

實例

-Xlog:gc=trace:file=gctrace.txt:uptimemillis,pid:filecount=5,filesize=1024

tag為gc，levle為trace，rotate文件數(shù)為5，每個文件1M，文件名為gctrace.txt，decrotators為uptimemillis和pid

輸出實例

[1110ms][1867] GC(2) Pause Remark 17M->17M(256M) 2.024ms
[1110ms][1867] GC(2) Finalize Live Data 0.000ms
[1110ms][1867] GC(2) Pause Cleanup 17M->17M(256M) 0.177ms
[1112ms][1867] GC(2) Concurrent Cycle 7.470ms
[2951ms][1867] GC(3) Pause Initial Mark (Metadata GC Threshold) 149M->30M(256M) 27.175ms
[2951ms][1867] GC(4) Concurrent Cycle
[2972ms][1867] GC(4) Pause Remark 32M->32M(256M) 5.132ms
[2974ms][1867] GC(4) Finalize Live Data 0.000ms
[2974ms][1867] GC(4) Pause Cleanup 32M->32M(256M) 0.214ms
[2976ms][1867] GC(4) Concurrent Cycle 25.422ms

遷移 舊版GC相關參數(shù)遷移

Legacy Garbage Collection (GC) Flag	Xlog Configuration	Comment
G1PrintHeapRegions	-Xlog:gc+region=trace	Not Applicable
GCLogFileSize	No configuration available	Log rotation is handled by the framework.
NumberOfGCLogFiles	Not Applicable	Log rotation is handled by the framework.
PrintAdaptiveSizePolicy	-Xlog:ergo*=level	Use a level of debug for most of the information, or a level of trace for all of what was logged for PrintAdaptiveSizePolicy.
PrintGC	-Xlog:gc	Not Applicable
PrintGCApplicationConcurrentTime	-Xlog:safepoint	Note that PrintGCApplicationConcurrentTime and PrintGCApplicationStoppedTime are logged on the same tag and aren’t separated in the new logging.
PrintGCApplicationStoppedTime	-Xlog:safepoint	Note that PrintGCApplicationConcurrentTime and PrintGCApplicationStoppedTime are logged on the same tag and not separated in the new logging.
PrintGCCause	Not Applicable	GC cause is now always logged.
PrintGCDateStamps	Not Applicable	Date stamps are logged by the framework.
PrintGCDetails	-Xlog:gc*	Not Applicable
PrintGCID	Not Applicable	GC ID is now always logged.
PrintGCTaskTimeStamps	-Xlog:task*=debug	Not Applicable
PrintGCTimeStamps	Not Applicable	Time stamps are logged by the framework.
PrintHeapAtGC	-Xlog:gc+heap=trace	Not Applicable
PrintReferenceGC	-Xlog:ref*=debug	Note that in the old logging, PrintReferenceGC had an effect only if PrintGCDetails was also enabled.
PrintStringDeduplicationStatistics	-Xlog:stringdedup*=debug	Not Applicable
PrintTenuringDistribution	-Xlog:age*=level	Use a level of debug for the most relevant information, or a level of trace for all of what was logged for PrintTenuringDistribution.
UseGCLogFileRotation	Not Applicable	What was logged for PrintTenuringDistribution.

舊版運行時參數(shù)遷移

Legacy Runtime Flag	Xlog Configuration	Comment
TraceExceptions	-Xlog:exceptions=info	Not Applicable
TraceClassLoading	-Xlog:class+load=level	Use level=info for regular information, or level=debug for additional information. In Unified Logging syntax, -verbose:class equals -Xlog:class+load=info,class+unload=info.
TraceClassLoadingPreorder	-Xlog:class+preorder=debug	Not Applicable
TraceClassUnloading	-Xlog:class+unload=level	Use level=info for regular information, or level=trace for additional information. In Unified Logging syntax, -verbose:class equals -Xlog:class+load=info,class+unload=info.
VerboseVerification	-Xlog:verification=info	Not Applicable
TraceClassPaths	-Xlog:class+path=info	Not Applicable
TraceClassResolution	-Xlog:class+resolve=debug	Not Applicable
TraceClassInitialization	-Xlog:class+init=info	Not Applicable
TraceLoaderConstraints	-Xlog:class+loader+constraints=info	Not Applicable
TraceClassLoaderData	-Xlog:class+loader+data=level	Use level=debug for regular information or level=trace for additional information.
TraceSafepointCleanupTime	-Xlog:safepoint+cleanup=info	Not Applicable
TraceSafepoint	-Xlog:safepoint=debug	Not Applicable
TraceMonitorInflation	-Xlog:monitorinflation=debug	Not Applicable
TraceBiasedLocking	-Xlog:biasedlocking=level	Use level=info for regular information, or level=trace for additional information.
TraceRedefineClasses	-Xlog:redefine+class*=level	level=info, =debug, and =trace provide increasing amounts of information.

小結

java9把gc log的配置統(tǒng)一到了Xlog中，可以按照官方給出的新舊參數(shù)映射表進行遷移。

doc

Enable Logging with the JVM Unified Logging Framework

-Xlog Output

Convert GC Logging Flags to Xlog

Convert Runtime Logging Flags to Xlog

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