13.3.虛擬化工具–jinfo詳解

實時查看和調整虛擬機的各項參數。

jinfo命令可以用來查看java進程運行的JVM參數，命令如下：

[root@admin ~]# jinfo --help Usage:jinfo [option] <pid>(to connect to running process)jinfo [option] <executable <core>(to connect to a core file)jinfo [option] [server_id@]<remote server IP or hostname>(to connect to remote debug server)where <option> is one of:-flag <name> to print the value of the named VM flag-flag [+|-]<name> to enable or disable the named VM flag-flag <name>=<value> to set the named VM flag to the given value-flags to print VM flags-sysprops to print Java system properties<no option> to print both of the above-h | -help to print this help message

我們先用 jps 命令查到 PID ，然后可以通過 jinfo 來查看對應進程的參數信息：

[root@admin ~]# jps 43520 Test 35900 Jps

查看JVM參數：

[root@admin ~]# jinfo -flags 43520 Attaching to process ID 43520, please wait... Debugger attached successfully. Server compiler detected. JVM version is 24.45-b08-Dfile.encoding=GBK

再如一個例子下面的Size的單位是Byte：

[admin@hadoop3 ~]$ jinfo -flags 449415 Attaching to process ID 449415, please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.60-b23 Non-default VM flags: -XX:+AlwaysPreTouch -XX:CICompilerCount=15 -XX:CMSInitiatingOccupancyFraction=75 -XX:ErrorFile=null -XX:GCLogFileSize=67108864 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=null -XX:InitialHeapSize=53687091200 -XX:MaxHeapSize=53687091200 -XX:MaxNewSize=3315138560 -XX:MaxTenuringThreshold=6 -XX:MinHeapDeltaBytes=196608 -XX:NewSize=3315138560 -XX:NumberOfGCLogFiles=32 -XX:OldPLABSize=16 -XX:OldSize=50371952640 -XX:-OmitStackTraceInFastThrow -XX:+PrintGC -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintTenuringDistribution -XX:ThreadStackSize=1024 -XX:+UseCMSInitiatingOccupancyOnly -XX:+UseConcMarkSweepGC -XX:+UseFastUnorderedTimeStamps -XX:+UseGCLogFileRotation -XX:+UseParNewGC Command line: -Xms50g -Xmx50g -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -Des.networkaddress.cache.ttl=60 -Des.networkaddress.cache.negative.ttl=10 -XX:+AlwaysPreTouch -Xss1m -Djava.awt.headless=true -Dfile.encoding=UTF-8 -Djna.nosys=true -XX:-OmitStackTraceInFastThrow -Dio.netty.noUnsafe=true -Dio.netty.noKeySetOptimization=true -Dio.netty.recycler.maxCapacityPerThread=0 -Dlog4j.shutdownHookEnabled=false -Dlog4j2.disable.jmx=true -Djava.io.tmpdir=/tmp/elasticsearch-9223305231604688595 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=data -XX:ErrorFile=logs/hs_err_pid%p.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime -Xloggc:logs/gc.log -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=32 -XX:GCLogFileSize=64m -Des.path.home=/home/admin/es/elasticsearch-6.7.1 -Des.path.conf=/home/admin/es/elasticsearch-6.7.1/config -Des.distribution.flavor=default -Des.distribution.type=tar [admin@hadoop3 ~]$

查看系統屬性：

[admin@hadoop3 ~]$ jinfo -sysprops 449415 Attaching to process ID 449415, please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.60-b23 jna.platform.library.path = /usr/lib64:/lib64:/usr/lib:/lib:/usr/lib64/qt-3.3/lib:/usr/lib64/mysql:/usr/lib64//bind9-export java.runtime.name = Java(TM) SE Runtime Environment sun.boot.library.path = /usr/java/jdk1.8.0_60/jre/lib/amd64 java.vm.version = 25.60-b23 es.path.home = /home/admin/es/elasticsearch-6.7.1 log4j.shutdownHookEnabled = false java.vendor.url = http://java.oracle.com/ java.vm.vendor = Oracle Corporation path.separator = : file.encoding.pkg = sun.io java.vm.name = Java HotSpot(TM) 64-Bit Server VM jna.loaded = true sun.os.patch.level = unknown user.country = CN sun.java.launcher = SUN_STANDARD es.networkaddress.cache.negative.ttl = 10 jna.nosys = true java.vm.specification.name = Java Virtual Machine Specification user.dir = /home/admin/es/elasticsearch-6.7.1 java.runtime.version = 1.8.0_60-b27 java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment java.endorsed.dirs = /usr/java/jdk1.8.0_60/jre/lib/endorsed os.arch = amd64 java.io.tmpdir = /tmp/elasticsearch-9223305231604688595 line.separator = es.networkaddress.cache.ttl = 60 es.logs.node_name = hadoop3 java.vm.specification.vendor = Oracle Corporation os.name = Linux io.netty.noKeySetOptimization = true sun.jnu.encoding = UTF-8 jnidispatch.path = /tmp/elasticsearch-9223305231604688595/jna-92668751/jna8806494672259821954.tmp java.library.path = /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib sun.nio.ch.bugLevel = es.logs.cluster_name = elasticsearch java.specification.name = Java Platform API Specification java.class.version = 52.0 sun.management.compiler = HotSpot 64-Bit Tiered Compilers os.version = 3.10.0-862.el7.x86_64 user.home = /home/admin user.timezone = Asia/Shanghai java.awt.printerjob = sun.print.PSPrinterJob file.encoding = UTF-8 java.specification.version = 1.8 es.distribution.type = tar io.netty.recycler.maxCapacityPerThread = 0 user.name = admin es.logs.base_path = /home/admin/es/eslogs java.class.path = /home/admin/es/elasticsearch-6.7.1/lib/elasticsearch-6.7.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/elasticsearch-x-content-6.7.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/elasticsearch-cli-6.7.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/elasticsearch-core-6.7.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/elasticsearch-secure-sm-6.7.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-core-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-analyzers-common-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-backward-codecs-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-grouping-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-highlighter-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-join-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-memory-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-misc-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-queries-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-queryparser-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-sandbox-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-spatial-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-spatial-extras-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-spatial3d-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/lucene-suggest-7.7.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/hppc-0.7.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/joda-time-2.10.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/t-digest-3.2.jar:/home/admin/es/elasticsearch-6.7.1/lib/HdrHistogram-2.1.9.jar:/home/admin/es/elasticsearch-6.7.1/lib/spatial4j-0.7.jar:/home/admin/es/elasticsearch-6.7.1/lib/jts-core-1.15.0.jar:/home/admin/es/elasticsearch-6.7.1/lib/log4j-api-2.11.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/log4j-core-2.11.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/log4j-1.2-api-2.11.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/jna-4.5.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/snakeyaml-1.17.jar:/home/admin/es/elasticsearch-6.7.1/lib/jackson-core-2.8.11.jar:/home/admin/es/elasticsearch-6.7.1/lib/jackson-dataformat-smile-2.8.11.jar:/home/admin/es/elasticsearch-6.7.1/lib/jackson-dataformat-yaml-2.8.11.jar:/home/admin/es/elasticsearch-6.7.1/lib/jackson-dataformat-cbor-2.8.11.jar:/home/admin/es/elasticsearch-6.7.1/lib/jopt-simple-5.0.2.jar:/home/admin/es/elasticsearch-6.7.1/lib/plugin-classloader-6.7.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/java-version-checker-6.7.1.jar:/home/admin/es/elasticsearch-6.7.1/lib/elasticsearch-launchers-6.7.1.jar es.path.conf = /home/admin/es/elasticsearch-6.7.1/config java.vm.specification.version = 1.8 java.home = /usr/java/jdk1.8.0_60/jre sun.java.command = org.elasticsearch.bootstrap.Elasticsearch -d sun.arch.data.model = 64 io.netty.noUnsafe = true user.language = zh java.specification.vendor = Oracle Corporation awt.toolkit = sun.awt.X11.XToolkit java.vm.info = mixed mode java.version = 1.8.0_60 java.ext.dirs = /usr/java/jdk1.8.0_60/jre/lib/ext:/usr/java/packages/lib/ext sun.boot.class.path = /usr/java/jdk1.8.0_60/jre/lib/resources.jar:/usr/java/jdk1.8.0_60/jre/lib/rt.jar:/usr/java/jdk1.8.0_60/jre/lib/sunrsasign.jar:/usr/java/jdk1.8.0_60/jre/lib/jsse.jar:/usr/java/jdk1.8.0_60/jre/lib/jce.jar:/usr/java/jdk1.8.0_60/jre/lib/charsets.jar:/usr/java/jdk1.8.0_60/jre/lib/jfr.jar:/usr/java/jdk1.8.0_60/jre/classes java.awt.headless = true java.vendor = Oracle Corporation file.separator = / java.vendor.url.bug = http://bugreport.sun.com/bugreport/ es.distribution.flavor = default sun.io.unicode.encoding = UnicodeLittle sun.cpu.endian = little log4j2.disable.jmx = true sun.cpu.isalist =

虛擬機的參數可以通過這個命令查看：

java -XX:+PrintFlagsFinal -version | grep manageable

除了通過啟動腳本可以設置參數，PrintGC 默認是打開的，因此我們只需要打開 PrintGCDetails 參數。

jinfo -flag +PrintGC 43520 jinfo -flag +PrintGCDetails 43520

關閉 GC 日志的話同理：

jinfo -flag -PrintGC 43520 jinfo -flag -PrintGCDetails 43520

查看是否開啟GC日志的打印：

jinfo -flag PrintGC 43520 jinfo -flag PrintGCDetails 43520[root@admin ~]# jinfo -flag PrintGC 43520 -XX:-PrintGC[root@admin ~]# jinfo -flag PrintGCDetails 43520 -XX:-PrintGCDetails

常用JVM參數：

-Xms：初始堆大小，默認為物理內存的1/64(<1GB)；默認(MinHeapFreeRatio參數可以調整)空余堆內存小于40%時，JVM就會增大堆直到-Xmx的最大限制 -Xmx：最大堆大小，默認(MaxHeapFreeRatio參數可以調整)空余堆內存大于70%時，JVM會減少堆直到 -Xms的最小限制 -Xmn：新生代的內存空間大小，注意：此處的大小是（eden+ 2 survivor space)。與jmap -heap中顯示的New gen是不同的。整個堆大小=新生代大小 + 老生代大小 + 永久代大小。在保證堆大小不變的情況下，增大新生代后,將會減小老生代大小。此值對系統性能影響較大,Sun官方推薦配置為整個堆的3/8。 -XX:SurvivorRatio：新生代中Eden區域與Survivor區域的容量比值，默認值為8。兩個Survivor區與一個Eden區的比值為2:8,一個Survivor區占整個年輕代的1/10。 -Xss：每個線程的堆棧大小。JDK5.0以后每個線程堆棧大小為1M,以前每個線程堆棧大小為256K。應根據應用的線程所需內存大小進行適當調整。在相同物理內存下,減小這個值能生成更多的線程。但是操作系統對一個進程內的線程數還是有限制的，不能無限生成，經驗值在3000~5000左右。一般小的應用， 如果棧不是很深， 應該是128k夠用的，大的應用建議使用256k。這個選項對性能影響比較大，需要嚴格的測試。和threadstacksize選項解釋很類似,官方文檔似乎沒有解釋,在論壇中有這樣一句話:"-Xss is translated in a VM flag named ThreadStackSize”一般設置這個值就可以了。 -XX:PermSize：設置永久代(perm gen)初始值。默認值為物理內存的1/64。 -XX:MaxPermSize：設置持久代最大值。物理內存的1/4。

: 后面的 + 或 - 表示使用或不使用。

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