Java gc 回收导致 cpu 虚高，用了 jstack 分析，一点头绪都没有，希望大家帮忙分析一下

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2020-04-08 15:47:54 Full thread dump Java HotSpot(TM) Server VM (25.152-b16 mixed mode):

"threadDeathWatcher-3-1" #29 daemon prio=1 os_prio=0 tid=0x1cf3e800 nid=0x5d6c sleeping[0x1845c000] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at org.apache.hbase.thirdparty.io.netty.util.ThreadDeathWatcher$Watcher.run(ThreadDeathWatcher.java:152) at org.apache.hbase.thirdparty.io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:138) at java.lang.Thread.run(Thread.java:748)

"RpcClient-timer-pool1-t1" #25 daemon prio=5 os_prio=0 tid=0x16d91800 nid=0x5d6b sleeping[0x184ad000] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at org.apache.hbase.thirdparty.io.netty.util.HashedWheelTimer$Worker.waitForNextTick(HashedWheelTimer.java:560) at org.apache.hbase.thirdparty.io.netty.util.HashedWheelTimer$Worker.run(HashedWheelTimer.java:459) at java.lang.Thread.run(Thread.java:748)

"Idle-Rpc-Conn-Sweeper-pool2-t1" #26 daemon prio=5 os_prio=0 tid=0x1cd51400 nid=0x5d68 waiting on condition [0x193fe000] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x32b10890> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078) at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093) at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809) at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)

"ReadOnlyZKClient-linux1:2181,linux2:2181,linux3:2181@0x01b403ee" #22 daemon prio=10 os_prio=0 tid=0x1faf7000 nid=0x5d65 waiting on condition [0x197fd000] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x32bf7ff8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078) at java.util.concurrent.DelayQueue.poll(DelayQueue.java:259) at org.apache.hadoop.hbase.zookeeper.ReadOnlyZKClient.run(ReadOnlyZKClient.java:303) at org.apache.hadoop.hbase.zookeeper.ReadOnlyZKClient$$Lambda$27/31456712.run(Unknown Source) at java.lang.Thread.run(Thread.java:748)

"OkHttp ConnectionPool" #18 daemon prio=5 os_prio=0 tid=0x1b4cf400 nid=0x5d5f in Object.wait() [0x1ddad000] java.lang.Thread.State: TIMED_WAITING (on object monitor) at java.lang.Object.wait(Native Method) at java.lang.Object.wait(Object.java:460) at com.squareup.okhttp.ConnectionPool.performCleanup(ConnectionPool.java:305) - locked <0x329bedb8> (a com.squareup.okhttp.ConnectionPool) at com.squareup.okhttp.ConnectionPool.runCleanupUntilPoolIsEmpty(ConnectionPool.java:242) at com.squareup.okhttp.ConnectionPool.access$000(ConnectionPool.java:54) at com.squareup.okhttp.ConnectionPool$1.run(ConnectionPool.java:97) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)

"Thread-3" #16 prio=5 os_prio=0 tid=0x1dc7d000 nid=0x5d57 runnable [0x1ddfe000] java.lang.Thread.State: RUNNABLE at java.net.SocketInputStream.socketRead0(Native Method) at java.net.SocketInputStream.socketRead(SocketInputStream.java:116) at java.net.SocketInputStream.read(SocketInputStream.java:171) at java.net.SocketInputStream.read(SocketInputStream.java:141) at java.net.SocketInputStream.read(SocketInputStream.java:127) at redis.clients.jedis.util.RedisInputStream.ensureFill(RedisInputStream.java:199) at redis.clients.jedis.util.RedisInputStream.readByte(RedisInputStream.java:43) at redis.clients.jedis.Protocol.process(Protocol.java:154) at redis.clients.jedis.Protocol.read(Protocol.java:219) at redis.clients.jedis.Connection.readProtocolWithCheckingBroken(Connection.java:309) at redis.clients.jedis.Connection.getRawObjectMultiBulkReply(Connection.java:276) at redis.clients.jedis.JedisPubSub.process(JedisPubSub.java:123) at redis.clients.jedis.JedisPubSub.proceed(JedisPubSub.java:117) at redis.clients.jedis.Jedis.subscribe(Jedis.java:2779) at redis.clients.jedis.JedisCluster$153.execute(JedisCluster.java:1693) at redis.clients.jedis.JedisCluster$153.execute(JedisCluster.java:1690) at redis.clients.jedis.JedisClusterCommand.runWithAnyNode(JedisClusterCommand.java:76) at redis.clients.jedis.JedisCluster.subscribe(JedisCluster.java:1696) at com.flo.recommend.init.RedisSubThread.run(RedisSubThread.java:28) at java.lang.Thread.run(Thread.java:748)

"commons-pool-evictor-thread" #14 prio=5 os_prio=0 tid=0x1dc4e800 nid=0x5d56 runnable [0x1e3ad000] java.lang.Thread.State: RUNNABLE at java.lang.Throwable.fillInStackTrace(Native Method) at java.lang.Throwable.fillInStackTrace(Throwable.java:783) - locked <0xcf435f08> (a java.lang.IllegalStateException) at java.lang.Throwable.<init>(Throwable.java:265) at java.lang.Exception.<init>(Exception.java:66) at java.lang.RuntimeException.<init>(RuntimeException.java:62) at java.lang.IllegalStateException.<init>(IllegalStateException.java:55) at org.apache.commons.pool2.impl.BaseGenericObjectPool.assertOpen(BaseGenericObjectPool.java:713) at org.apache.commons.pool2.impl.GenericObjectPool.evict(GenericObjectPool.java:721) at org.apache.commons.pool2.impl.BaseGenericObjectPool$Evictor.run(BaseGenericObjectPool.java:1077) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)

"Thread-1" #11 prio=5 os_prio=0 tid=0x1eaee400 nid=0x5d54 sleeping[0x1e3fe000] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at com.flo.recommend.reduce.PushUrlCache.run(PushUrlCache.java:55) at java.lang.Thread.run(Thread.java:748)

"Thread-0" #10 prio=5 os_prio=0 tid=0x1e90d400 nid=0x5d53 runnable [0x1e652000] java.lang.Thread.State: RUNNABLE at com.flo.recommend.util.MyLevenshtein.levenshtein(MyLevenshtein.java:19) at com.flo.recommend.mahout.DistancesRedue.apprun(DistancesRedue.java:70) at com.flo.recommend.init.RedisInit.initAppInfo(RedisInit.java:129) at com.flo.recommend.init.RedisInit.run(RedisInit.java:37) at java.lang.Thread.run(Thread.java:748)

"mysql-cj-abandoned-connection-cleanup" #9 daemon prio=5 os_prio=0 tid=0x1fc77800 nid=0x5d52 runnable [0x20d95000] java.lang.Thread.State: RUNNABLE at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findResource(URLClassLoader.java:566) at java.lang.ClassLoader.getResource(ClassLoader.java:1096) at java.lang.ClassLoader.getResource(ClassLoader.java:1091) at java.lang.ClassLoader.getResource(ClassLoader.java:1091) at com.mysql.jdbc.AbandonedConnectionCleanupThread.checkThreadContextClassLoader(AbandonedConnectionCleanupThread.java:112) at com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:79) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)

"Service Thread" #8 daemon prio=9 os_prio=0 tid=0x216aac00 nid=0x5d50 runnable [0x00000000] java.lang.Thread.State: RUNNABLE

"C1 CompilerThread2" #7 daemon prio=9 os_prio=0 tid=0x216a7800 nid=0x5d4f waiting on condition [0x00000000] java.lang.Thread.State: RUNNABLE

"C2 CompilerThread1" #6 daemon prio=9 os_prio=0 tid=0x216a6400 nid=0x5d4e waiting on condition [0x00000000] java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" #5 daemon prio=9 os_prio=0 tid=0x216a4400 nid=0x5d4d runnable [0x00000000] java.lang.Thread.State: RUNNABLE

"Signal Dispatcher" #4 daemon prio=9 os_prio=0 tid=0x216a2c00 nid=0x5d4c runnable [0x00000000] java.lang.Thread.State: RUNNABLE

"Finalizer" #3 daemon prio=8 os_prio=0 tid=0x21688800 nid=0x5d4b in Object.wait() [0x28a7d000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143) - locked <0x29ebc1b0> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:164) at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)

"Reference Handler" #2 daemon prio=10 os_prio=0 tid=0x21685c00 nid=0x5d4a in Object.wait() [0x2157d000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) at java.lang.Object.wait(Object.java:502) at java.lang.ref.Reference.tryHandlePending(Reference.java:191) - locked <0x29ebc3b0> (a java.lang.ref.Reference$Lock) at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)

"main" #1 prio=5 os_prio=0 tid=0xf7607000 nid=0x5d44 in Object.wait() [0xf7788000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x29ebc4b0> (a io.netty.channel.AbstractChannel$CloseFuture) at java.lang.Object.wait(Object.java:502) at io.netty.util.concurrent.DefaultPromise.await(DefaultPromise.java:231) - locked <0x29ebc4b0> (a io.netty.channel.AbstractChannel$CloseFuture) at io.netty.channel.DefaultChannelPromise.await(DefaultChannelPromise.java:131) at io.netty.channel.DefaultChannelPromise.await(DefaultChannelPromise.java:30) at io.netty.util.concurrent.DefaultPromise.sync(DefaultPromise.java:337) at io.netty.channel.DefaultChannelPromise.sync(DefaultChannelPromise.java:119) at io.netty.channel.DefaultChannelPromise.sync(DefaultChannelPromise.java:30) at com.flo.recommend.HttpServer.main(HttpServer.java:110) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)

"VM Thread" os_prio=0 tid=0x21681000 nid=0x5d49 runnable

"GC task thread#0 (ParallelGC)" os_prio=0 tid=0xf7610800 nid=0x5d45 runnable

"GC task thread#1 (ParallelGC)" os_prio=0 tid=0xf7611c00 nid=0x5d46 runnable

"GC task thread#2 (ParallelGC)" os_prio=0 tid=0xf7613000 nid=0x5d47 runnable

"GC task thread#3 (ParallelGC)" os_prio=0 tid=0xf7614400 nid=0x5d48 runnable

"VM Periodic Task Thread" os_prio=0 tid=0x216bf000 nid=0x5d51 waiting on condition

JNI global references: 431

20 条回复 • 2020-04-27 17:59:52 +08:00

myz2018

2020-04-09 10:40:43 +08:00

cpu 看 top -H 。然后找到对应的线程号。转 16 机制。然后再用 jstack.看。ps.你怎么知道是 gc 导致的？

araraloren

2020-04-09 10:51:32 +08:00

虚高是什么意思。。？

realpg

2020-04-09 10:53:16 +08:00

我好奇你是怎么得出“虚” 这个结论的

Aresxue

2020-04-09 10:55:34 +08:00

gc 占用的 cpu 已经很少了，不知道你怎么先入为主得出这个结论的。顺便吐槽下 gc 日志不给，只给个线程的快照有什么用

hcymk2

2020-04-09 10:58:10 +08:00

github.com/oldratlee/useful-scripts/blob/master/show-busy-java-threads

securityCoding

2020-04-09 11:30:41 +08:00

jvm 调优是门玄学,劝君慎入此道

simonlu9

2020-04-09 11:53:24 +08:00

@myz2018 我也是按照这个方法去定位 cpu 线程的，确实是回收线程导致 cpu 很高

simonlu9

2020-04-09 11:53:46 +08:00

@araraloren cpu 达到 300%

huntcool001

2020-04-09 12:06:10 +08:00

是 JDK8 吗? 改 G1,重启,问题解决. /doge

tt0411

2020-04-09 12:17:52 +08:00

先确定下是不是 gc 问题: dump gc 日志, 看看 gc 时间和频率; cpu 300% 不太像是 gc 导致的

icegreen

2020-04-09 13:53:28 +08:00

jstat -gcutil 1000

ty916

2020-04-09 13:58:14 +08:00

可以试试 jmap -dump:format=b,file=serviceDump.dat 进程号导出 dump 文件，然后用 jprofile 分析下，那个类占用内存最大，定位到那个线程，再看线程的堆栈日志

CFM880

2020-04-09 14:05:24 +08:00

难道不是先定位 cpu 占用过高的进程，后定位该进程下的哪个线程 CPU 占用过高的么
top -m 10 -n 1 -s cpu
top -t | grep "pid"

gz911122

2020-04-09 14:08:15 +08:00

我好奇你是怎么得出“虚” 这个结论的

simonlu9

2020-04-09 14:30:45 +08:00

@huntcool001 是的，jdk8 环境,我试试

rihkddd

2020-04-09 15:42:48 +08:00

如果你已经确定了是 GC 导致的 CPU 占用，问题其实是要找内存泄漏点。可行的方法，使用 jcmd 统计堆内对象计数（先把问题复现），主要关注排名靠前的自己代码中 new 的对象，基本然后关注一下 new 这些对象的地方，基本上大概可以确定。还不是很确定可以用 idea 调试，关注上述代码逻辑，看是不是持续的，idea 调试的时候有窗口可以看到对象计数，占用内存大小。调试下来基本上都能找到问题点。

bobuick

2020-04-09 15:51:47 +08:00

gc 日志一打，分分钟就知道是不是 gc 导致的 cpu 高了。

simonlu9

2020-04-10 09:58:06 +08:00

@rihkddd 是的，找到了 AtomicLong 类型占用内存最多，但是引用的类有很多，现在用排除法来试试那部分代码出的问题

ElmerZhang

2020-04-10 10:17:57 +08:00

很久没用 Java 了，是 mat 已经过时了么？为什么没人提到这个呢？我印象中分析内存泄漏的话 mat 比 jprofiler 方便。

simonlu9

2020-04-27 17:59:52 +08:00

@simonlu9 已解决