本文基于OpenJDK 11
最近使用Spring Cloud Gateway的时候，遇到了一个奇怪的问题：
线上有3个 API 网关实例，压力均衡，平稳运行3天后，突然有一个实例，CPU飚高，并且响应时间增加很多，从几十毫秒涨到了几分钟。
线上是 k8s 管理容器，立刻停掉了这个 pod，重建，恢复正常。
线上我们开启了 JFR 记录（可以参考我的另外系列文章：Java 监控 JFR），通过 JMC 查看下出问题的 JFR 记录。
首先我们来看 GC，我们的 GC 算法是 G1，主要通过 G1 Garbage Collection这个事件查看：
发现 GC 全部为 Young GC，且耗时比较正常，频率上也没有什么明显异常。
接下来来看，CPU 占用相关。直接看 Thread CPU Load 这个事件，看每个线程的 CPU 占用情况。发现reactor-http-epoll线程池的线程，CPU 占用很高，加在一起，接近了 100%。
这些线程是 reactor-netty 处理业务的线程，观察其他实例，发现正常情况下，并不会有这么高的 CPU 负载。那么为啥会有这么高的负载呢？通过 Thread Dump 来看一下线程堆栈有何发现.
通过查看多个线程堆栈 dump，发现这些线程基本都处于 Runnable，并且执行的方法是原生方法，和StackWalker相关，例如：
"reactor-http-epoll-2" #75 daemon prio=5 os_prio=0 cpu=25100145.64ms elapsed=306507.26s tid=0x0000556eddcbd000 nid=0x61 runnable [0x00007f8605443000]
java.lang.Thread.State: RUNNABLE
at java.lang.StackStreamFactory$AbstractStackWalker.callStackWalk(java.base@11.0.6/Native Method)
at java.lang.StackStreamFactory$AbstractStackWalker.beginStackWalk(java.base@11.0.6/StackStreamFactory.java:370)
at java.lang.StackStreamFactory$AbstractStackWalker.walk(java.base@11.0.6/StackStreamFactory.java:243)
at java.lang.StackWalker.walk(java.base@11.0.6/StackWalker.java:498)
at org.apache.logging.log4j.util.StackLocator.calcLocation(StackLocator.java:81)
at org.apache.logging.log4j.util.StackLocatorUtil.calcLocation(StackLocatorUtil.java:76)
at org.apache.logging.log4j.spi.AbstractLogger.getLocation(AbstractLogger.java:2201)
at org.apache.logging.log4j.spi.AbstractLogger.logMessageTrackRecursion(AbstractLogger.java:2144)
at org.apache.logging.log4j.spi.AbstractLogger.logMessageSafely(AbstractLogger.java:2127)
at org.apache.logging.log4j.spi.AbstractLogger.logMessage(AbstractLogger.java:2020)
at org.apache.logging.log4j.spi.AbstractLogger.logIfEnabled(AbstractLogger.java:1891)
at org.apache.logging.log4j.spi.AbstractLogger.info(AbstractLogger.java:1436)
at com.xxx.apigateway.filter.AccessCheckFilter.filter(AccessCheckFilter.java:144)
at org.springframework.cloud.gateway.handler.FilteringWebHandler$GatewayFilterAdapter.filter(FilteringWebHandler.java:138)
at org.springframework.cloud.gateway.filter.OrderedGatewayFilter.filter(OrderedGatewayFilter.java:44)
at org.springframework.cloud.gateway.handler.FilteringWebHandler$DefaultGatewayFilterChain.lambda$filter$0(FilteringWebHandler.java:118)
at org.springframework.cloud.gateway.handler.FilteringWebHandler$DefaultGatewayFilterChain$$Lambda$1265/0x0000000800b83440.get(Unknown Source)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:44)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.Mono.subscribe(Mono.java:4105)
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:172)
at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:150)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:76)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:274)
at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:851)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1637)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onNext(MonoFlatMap.java:241)
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2199)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onSubscribe(MonoFlatMap.java:230)
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:150)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:76)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:274)
at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:851)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:73)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onNext(MonoPeekTerminal.java:173)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1637)
at reactor.core.publisher.MonoFilterWhen$MonoFilterWhenMain.innerResult(MonoFilterWhen.java:193)
at reactor.core.publisher.MonoFilterWhen$FilterWhenInner.onNext(MonoFilterWhen.java:260)
at reactor.core.publisher.MonoFilterWhen$FilterWhenInner.onNext(MonoFilterWhen.java:228)
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2199)
at reactor.core.publisher.MonoFilterWhen$FilterWhenInner.onSubscribe(MonoFilterWhen.java:249)
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54)
at reactor.core.publisher.Mono.subscribe(Mono.java:4105)
at reactor.core.publisher.MonoFilterWhen$MonoFilterWhenMain.onNext(MonoFilterWhen.java:150)
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2199)
at reactor.core.publisher.MonoFilterWhen$MonoFilterWhenMain.onSubscribe(MonoFilterWhen.java:103)
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54)
at reactor.core.publisher.Mono.subscribe(Mono.java:4105)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:441)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onNext(FluxConcatMap.java:243)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxDematerialize$DematerializeSubscriber.onNext(FluxDematerialize.java:91)
at reactor.core.publisher.FluxDematerialize$DematerializeSubscriber.onNext(FluxDematerialize.java:38)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxIterable$IterableSubscription.slowPath(FluxIterable.java:243)
at reactor.core.publisher.FluxIterable$IterableSubscription.request(FluxIterable.java:201)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.request(ScopePassingSpanSubscriber.java:76)
at reactor.core.publisher.FluxDematerialize$DematerializeSubscriber.request(FluxDematerialize.java:120)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.request(ScopePassingSpanSubscriber.java:76)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.request(ScopePassingSpanSubscriber.java:76)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:228)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onSubscribe(ScopePassingSpanSubscriber.java:69)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onSubscribe(ScopePassingSpanSubscriber.java:69)
at reactor.core.publisher.FluxDematerialize$DematerializeSubscriber.onSubscribe(FluxDematerialize.java:70)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onSubscribe(ScopePassingSpanSubscriber.java:69)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:139)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:63)
at reactor.core.publisher.InternalFluxOperator.subscribe(InternalFluxOperator.java:53)
at reactor.core.publisher.FluxDefer.subscribe(FluxDefer.java:54)
at reactor.core.publisher.Mono.subscribe(Mono.java:4105)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:441)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onNext(FluxConcatMap.java:243)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxIterable$IterableSubscription.slowPath(FluxIterable.java:243)
at reactor.core.publisher.FluxIterable$IterableSubscription.request(FluxIterable.java:201)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.request(ScopePassingSpanSubscriber.java:76)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:228)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onSubscribe(ScopePassingSpanSubscriber.java:69)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:139)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:63)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at org.springframework.cloud.sleuth.instrument.web.TraceWebFilter$MonoWebFilterTrace.subscribe(TraceWebFilter.java:162)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.Mono.subscribe(Mono.java:4105)
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:172)
at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.netty.http.server.HttpServerHandle.onStateChange(HttpServerHandle.java:64)
at reactor.netty.tcp.TcpServerBind$ChildObserver.onStateChange(TcpServerBind.java:228)
at reactor.netty.http.server.HttpServerOperations.onInboundNext(HttpServerOperations.java:465)
at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:90)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
at reactor.netty.http.server.HttpTrafficHandler.channelRead(HttpTrafficHandler.java:167)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:321)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:308)
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:422)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276)
at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:792)
at io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe$1.run(AbstractEpollChannel.java:387)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:384)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(java.base@11.0.6/Thread.java:834)
"reactor-http-epoll-4" #79 daemon prio=5 os_prio=0 cpu=25266372.53ms elapsed=306415.58s tid=0x0000556eddcc4800 nid=0x65 runnable [0x00007f85e2ff9000]
java.lang.Thread.State: RUNNABLE
at java.lang.StackStreamFactory$AbstractStackWalker.fetchStackFrames(java.base@11.0.6/Native Method)
at java.lang.StackStreamFactory$AbstractStackWalker.fetchStackFrames(java.base@11.0.6/StackStreamFactory.java:386)
at java.lang.StackStreamFactory$AbstractStackWalker.getNextBatch(java.base@11.0.6/StackStreamFactory.java:322)
at java.lang.StackStreamFactory$AbstractStackWalker.peekFrame(java.base@11.0.6/StackStreamFactory.java:263)
at java.lang.StackStreamFactory$AbstractStackWalker.hasNext(java.base@11.0.6/StackStreamFactory.java:351)
at java.lang.StackStreamFactory$StackFrameTraverser.nextStackFrame(java.base@11.0.6/StackStreamFactory.java:520)
at java.lang.StackStreamFactory$StackFrameTraverser.forEachRemaining(java.base@11.0.6/StackStreamFactory.java:581)
at java.util.stream.AbstractPipeline.copyInto(java.base@11.0.6/AbstractPipeline.java:484)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(java.base@11.0.6/AbstractPipeline.java:474)
at java.util.stream.AbstractPipeline.evaluate(java.base@11.0.6/AbstractPipeline.java:550)
at java.util.stream.AbstractPipeline.evaluateToArrayNode(java.base@11.0.6/AbstractPipeline.java:260)
at java.util.stream.ReferencePipeline.toArray(java.base@11.0.6/ReferencePipeline.java:517)
at java.util.stream.ReferencePipeline.toArray(java.base@11.0.6/ReferencePipeline.java:523)
at org.apache.logging.log4j.util.StackLocator$FqcnCallerLocator.apply(StackLocator.java:96)
at org.apache.logging.log4j.util.StackLocator$FqcnCallerLocator.apply(StackLocator.java:90)
at java.lang.StackStreamFactory$StackFrameTraverser.consumeFrames(java.base@11.0.6/StackStreamFactory.java:534)
at java.lang.StackStreamFactory$AbstractStackWalker.doStackWalk(java.base@11.0.6/StackStreamFactory.java:306)
at java.lang.StackStreamFactory$AbstractStackWalker.callStackWalk(java.base@11.0.6/Native Method)
at java.lang.StackStreamFactory$AbstractStackWalker.beginStackWalk(java.base@11.0.6/StackStreamFactory.java:370)
at java.lang.StackStreamFactory$AbstractStackWalker.walk(java.base@11.0.6/StackStreamFactory.java:243)
at java.lang.StackWalker.walk(java.base@11.0.6/StackWalker.java:498)
at org.apache.logging.log4j.util.StackLocator.calcLocation(StackLocator.java:81)
at org.apache.logging.log4j.util.StackLocatorUtil.calcLocation(StackLocatorUtil.java:76)
at org.apache.logging.log4j.spi.AbstractLogger.getLocation(AbstractLogger.java:2201)
at org.apache.logging.log4j.spi.AbstractLogger.logMessageTrackRecursion(AbstractLogger.java:2144)
at org.apache.logging.log4j.spi.AbstractLogger.logMessageSafely(AbstractLogger.java:2127)
at org.apache.logging.log4j.spi.AbstractLogger.logMessage(AbstractLogger.java:2038)
at org.apache.logging.log4j.spi.AbstractLogger.logIfEnabled(AbstractLogger.java:1915)
at org.apache.logging.log4j.spi.AbstractLogger.info(AbstractLogger.java:1451)
at com.xxx.apigateway.filter.CommonLogFilter.filter(CommonLogFilter.java:42)
at org.springframework.cloud.gateway.handler.FilteringWebHandler$GatewayFilterAdapter.filter(FilteringWebHandler.java:138)
at org.springframework.cloud.gateway.filter.OrderedGatewayFilter.filter(OrderedGatewayFilter.java:44)
at org.springframework.cloud.gateway.handler.FilteringWebHandler$DefaultGatewayFilterChain.lambda$filter$0(FilteringWebHandler.java:118)
at org.springframework.cloud.gateway.handler.FilteringWebHandler$DefaultGatewayFilterChain$$Lambda$1265/0x0000000800b83440.get(Unknown Source)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:44)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.Mono.subscribe(Mono.java:4105)
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:172)
at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:150)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:76)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:274)
at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:851)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1637)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onNext(MonoFlatMap.java:241)
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2199)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onSubscribe(MonoFlatMap.java:230)
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:150)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:76)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:274)
at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:851)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:73)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onNext(MonoPeekTerminal.java:173)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1637)
at reactor.core.publisher.MonoFilterWhen$MonoFilterWhenMain.innerResult(MonoFilterWhen.java:193)
at reactor.core.publisher.MonoFilterWhen$FilterWhenInner.onNext(MonoFilterWhen.java:260)
at reactor.core.publisher.MonoFilterWhen$FilterWhenInner.onNext(MonoFilterWhen.java:228)
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2199)
at reactor.core.publisher.MonoFilterWhen$FilterWhenInner.onSubscribe(MonoFilterWhen.java:249)
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54)
at reactor.core.publisher.Mono.subscribe(Mono.java:4105)
at reactor.core.publisher.MonoFilterWhen$MonoFilterWhenMain.onNext(MonoFilterWhen.java:150)
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2199)
at reactor.core.publisher.MonoFilterWhen$MonoFilterWhenMain.onSubscribe(MonoFilterWhen.java:103)
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54)
at reactor.core.publisher.Mono.subscribe(Mono.java:4105)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:441)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onNext(FluxConcatMap.java:243)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxDematerialize$DematerializeSubscriber.onNext(FluxDematerialize.java:91)
at reactor.core.publisher.FluxDematerialize$DematerializeSubscriber.onNext(FluxDematerialize.java:38)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxIterable$IterableSubscription.slowPath(FluxIterable.java:243)
at reactor.core.publisher.FluxIterable$IterableSubscription.request(FluxIterable.java:201)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.request(ScopePassingSpanSubscriber.java:76)
at reactor.core.publisher.FluxDematerialize$DematerializeSubscriber.request(FluxDematerialize.java:120)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.request(ScopePassingSpanSubscriber.java:76)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.request(ScopePassingSpanSubscriber.java:76)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:228)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onSubscribe(ScopePassingSpanSubscriber.java:69)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onSubscribe(ScopePassingSpanSubscriber.java:69)
at reactor.core.publisher.FluxDematerialize$DematerializeSubscriber.onSubscribe(FluxDematerialize.java:70)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onSubscribe(ScopePassingSpanSubscriber.java:69)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:139)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:63)
at reactor.core.publisher.InternalFluxOperator.subscribe(InternalFluxOperator.java:53)
at reactor.core.publisher.FluxDefer.subscribe(FluxDefer.java:54)
at reactor.core.publisher.Mono.subscribe(Mono.java:4105)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:441)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onNext(FluxConcatMap.java:243)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:90)
at reactor.core.publisher.FluxIterable$IterableSubscription.slowPath(FluxIterable.java:243)
at reactor.core.publisher.FluxIterable$IterableSubscription.request(FluxIterable.java:201)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.request(ScopePassingSpanSubscriber.java:76)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:228)
at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onSubscribe(ScopePassingSpanSubscriber.java:69)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:139)
at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:63)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at org.springframework.cloud.sleuth.instrument.web.TraceWebFilter$MonoWebFilterTrace.subscribe(TraceWebFilter.java:162)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.Mono.subscribe(Mono.java:4105)
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:172)
at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
at reactor.netty.http.server.HttpServerHandle.onStateChange(HttpServerHandle.java:64)
at reactor.netty.tcp.TcpServerBind$ChildObserver.onStateChange(TcpServerBind.java:228)
at reactor.netty.http.server.HttpServerOperations.onInboundNext(HttpServerOperations.java:465)
at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:90)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
at reactor.netty.http.server.HttpTrafficHandler.channelRead(HttpTrafficHandler.java:167)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:321)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:295)
at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:792)
at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:475)
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:378)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(java.base@11.0.6/Thread.java:834)
主要和这两个原生方法有关：
java.lang.StackStreamFactory$AbstractStackWalker.callStackWalkjava.lang.StackStreamFactory$AbstractStackWalker.fetchStackFrames
虽然一直有OpenJDK 11 之后， StackWalker性能有问题，不如new Throwable()获取堆栈快的问题。但是考虑到压力是均衡的，其他两个实例并没有这个问题，应该不是本身对于这个类的应用，导致的CPU消耗突然变大。查看 JDK 相关的 JIRA，发现一个有意思的 BUG：Application on JDK11 consume 100% CPU after a few hours of uptime
这里面说，java.lang.StackStreamFactory$AbstractStackWalker.callStackWalk这个原生方法，在 JVM 运行几小时后，突然 CPU 就会飚高到 100%。看来可能确实有些问题。针对这个问题，我也提了个 Issue 到 Log4j 的 JIRA：High CPU consumption using StackWalker
那么为什么会调用这个类呢？Log4j2 打异步日志的时候，如果需要保留日志产生的类还有行号，需要缓存堆栈，那么需要配置includeLocation = true。这个堆栈，如果环境是 java 9 之前，那么通过 new Throwable() 实现， 参考：StackLocator.java 如果环境是 java 9 之后，那么通过 StackWalker 实现：StackLocator.java 这个如果你配置了includeLocation = true，就会缓存堆栈。
对于网关，我们可以不用打印类和行号，配置includeLocation = false可以避免再出现类似的问题。
以后在应用中，
今天的文章JFR定位由于可能的JDK11的bug导致Log4j2 CPU占用100%的问题分享到此就结束了，感谢您的阅读。
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