应用程序速度慢，JVM频繁挂起，使用单CPU设置和Java 12 +

java java-14 freeze

2022-09-01 13:23:52

我们有一个客户端应用程序（经过10多年的开发）。它的JDK最近从OpenJDK 11升级到OpenJDK 14。在单CPU（禁用超线程）Windows 10设置（以及只有一个可用CPU的VirtualBox机器内部）上，与Java 11相比，应用程序的启动速度非常慢。此外，它大部分时间都使用100%的CPU。我们还可以重现将处理器关联设置为仅一个 CPU （）的问题。c:\windows\system32\cmd.exe /C start /affinity 1 ...

在我的VirtualBox机器中启动应用程序并以最少的手动交互执行查询的一些测量：

打开JDK 11.0.2：36 秒
OpenJDK 13.0.2：约 1.5 分钟
打开JDK 13.0.2 与： 46 秒-XX:-UseBiasedLocking
打开JDK 13.0.2 与： 40 秒-XX:-ThreadLocalHandshakes
打开JDK 14：5-6 分钟
打开JDK 14 与： 3-3，5 分钟-XX:-UseBiasedLocking
OpenJDK 15 EA Build 20： ~4，5 分钟

只有使用的 JDK（以及提到的选项）已更改。（在 Java 14 中不可用。-XX:-ThreadLocalHandshakes

我们尝试记录 JDK 14 对 .-Xlog:all=debug:file=app.txt:uptime,tid,level,tags:filecount=50

使用 OpenJDK 11.0.2 计算每秒的对数行似乎非常顺利：

$ cat jdk11-log/app* | grep "^\[" | cut -d. -f 1 | cut -d[ -f 2 | sort | uniq -c | sort -k 2 -n
  30710 0
  44012 1
  55461 2
  55974 3
  27182 4
  41292 5
  43796 6
  51889 7
  54170 8
  58850 9
  51422 10
  44378 11
  41405 12
  53589 13
  41696 14
  29526 15
   2350 16
  50228 17
  62623 18
  42684 19
  45045 20

另一方面，OpenJDK 14似乎有有趣的安静时期：

$ cat jdk14-log/app* | grep "^\[" | cut -d. -f 1 | cut -d[ -f 2 | sort | uniq -c | sort -k 2 -n
   7726 0
   1715 5
  10744 6
   4341 11
  42792 12
  45979 13
  38783 14
  17253 21
  34747 22
   1025 28
   2079 33
   2398 39
   3016 44

那么，在1-4秒，7-10秒和14-20秒之间发生了什么？

...
[0.350s][7248][debug][class,resolve        ] jdk.internal.ref.CleanerFactory$1 java.lang.Thread CleanerFactory.java:45
[0.350s][7248][debug][class,resolve        ] jdk.internal.ref.CleanerImpl java.lang.Thread CleanerImpl.java:117
[0.350s][7248][info ][biasedlocking        ] Aligned thread 0x000000001727e010 to 0x000000001727e800
[0.350s][7248][info ][os,thread            ] Thread started (tid: 2944, attributes: stacksize: default, flags: CREATE_SUSPENDED STACK_SIZE_PARAM_IS)
[0.350s][6884][info ][os,thread            ] Thread is alive (tid: 6884).
[0.350s][6884][debug][os,thread            ] Thread 6884 stack dimensions: 0x00000000175b0000-0x00000000176b0000 (1024k).
[0.350s][6884][debug][os,thread            ] Thread 6884 stack guard pages activated: 0x00000000175b0000-0x00000000175b4000.
[0.350s][7248][debug][thread,smr           ] tid=7248: Threads::add: new ThreadsList=0x0000000017254500
[0.350s][7248][debug][thread,smr           ] tid=7248: ThreadsSMRSupport::free_list: threads=0x0000000017253d50 is freed.
[0.350s][2944][info ][os,thread            ] Thread is alive (tid: 2944).
[0.350s][2944][debug][os,thread            ] Thread 2944 stack dimensions: 0x00000000177b0000-0x00000000178b0000 (1024k).
[0.350s][2944][debug][os,thread            ] Thread 2944 stack guard pages activated: 0x00000000177b0000-0x00000000177b4000.
[0.351s][2944][debug][class,resolve        ] java.lang.Thread java.lang.Runnable Thread.java:832
[0.351s][2944][debug][class,resolve        ] jdk.internal.ref.CleanerImpl jdk.internal.misc.InnocuousThread CleanerImpl.java:135
[0.351s][2944][debug][class,resolve        ] jdk.internal.ref.CleanerImpl jdk.internal.ref.PhantomCleanable CleanerImpl.java:138
[0.351s][2944][info ][biasedlocking,handshake] JavaThread 0x000000001727e800 handshaking JavaThread 0x000000000286d800 to revoke object 0x00000000c0087f78
[0.351s][2944][debug][vmthread               ] Adding VM operation: HandshakeOneThread
[0.351s][6708][debug][vmthread               ] Evaluating non-safepoint VM operation: HandshakeOneThread
[0.351s][6708][debug][vmoperation            ] begin VM_Operation (0x00000000178af250): HandshakeOneThread, mode: no safepoint, requested by thread 0x000000001727e800

# no log until 5.723s

[5.723s][7248][info ][biasedlocking          ]   Revoked bias of currently-unlocked object
[5.723s][7248][debug][handshake,task         ] Operation: RevokeOneBias for thread 0x000000000286d800, is_vm_thread: false, completed in 94800 ns
[5.723s][7248][debug][class,resolve          ] java.util.zip.ZipFile$CleanableResource java.lang.ref.Cleaner ZipFile.java:715
[5.723s][7248][debug][class,resolve          ] java.lang.ref.Cleaner jdk.internal.ref.CleanerImpl$PhantomCleanableRef Cleaner.java:220
[5.723s][7248][debug][class,resolve          ] java.util.zip.ZipFile$CleanableResource java.util.WeakHashMap ZipFile.java:716
...

稍稍稍之后的第二个停顿：

...
[6.246s][7248][info ][class,load              ] java.awt.Graphics source: jrt:/java.desktop
[6.246s][7248][debug][class,load              ]  klass: 0x0000000100081a00 super: 0x0000000100001080 loader: [loader data: 0x0000000002882bd0 of 'bootstrap'] bytes: 5625 checksum: 0025818f
[6.246s][7248][debug][class,resolve           ] java.awt.Graphics java.lang.Object (super)
[6.246s][7248][info ][class,loader,constraints] updating constraint for name java/awt/Graphics, loader 'bootstrap', by setting class object
[6.246s][7248][debug][jit,compilation         ]   19       4       java.lang.Object::<init> (1 bytes)   made not entrant
[6.246s][7248][debug][vmthread                ] Adding VM operation: HandshakeAllThreads
[6.246s][6708][debug][vmthread                ] Evaluating non-safepoint VM operation: HandshakeAllThreads
[6.246s][6708][debug][vmoperation             ] begin VM_Operation (0x000000000203ddf8): HandshakeAllThreads, mode: no safepoint, requested by thread 0x000000000286d800
[6.246s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026b0800, is_vm_thread: true, completed in 1400 ns
[6.246s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026bb800, is_vm_thread: true, completed in 700 ns
[6.246s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026ef800, is_vm_thread: true, completed in 100 ns
[6.246s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026f0800, is_vm_thread: true, completed in 100 ns
[6.246s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026f1800, is_vm_thread: true, completed in 100 ns
[6.246s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026f4800, is_vm_thread: true, completed in 100 ns
[6.247s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x0000000002768800, is_vm_thread: true, completed in 100 ns
[6.247s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x000000000276e000, is_vm_thread: true, completed in 100 ns
[6.247s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x0000000017268800, is_vm_thread: true, completed in 100 ns
[6.247s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x000000001727e800, is_vm_thread: true, completed in 800 ns

# no log until 11.783s

[11.783s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x000000000286d800, is_vm_thread: true, completed in 6300 ns
[11.783s][6708][info ][handshake               ] Handshake "Deoptimize", Targeted threads: 11, Executed by targeted threads: 0, Total completion time: 5536442500 ns
[11.783s][6708][debug][vmoperation             ] end VM_Operation (0x000000000203ddf8): HandshakeAllThreads, mode: no safepoint, requested by thread 0x000000000286d800
[11.783s][7248][debug][protectiondomain        ] Checking package access
[11.783s][7248][debug][protectiondomain        ] class loader: a 'jdk/internal/loader/ClassLoaders$AppClassLoader'{0x00000000c0058628} protection domain: a 'java/security/ProtectionDomain'{0x00000000c058b948} loading: 'java/awt/Graphics'
[11.783s][7248][debug][protectiondomain        ] granted
[11.783s][7248][debug][class,resolve           ] sun.launcher.LauncherHelper java.awt.Graphics LauncherHelper.java:816 (reflection)
[11.783s][7248][debug][class,resolve           ] jdk.internal.reflect.Reflection [Ljava.lang.reflect.Method; Reflection.java:300
[11.783s][7248][debug][class,preorder          ] java.lang.PublicMethods$MethodList source: C:\Users\example\AppData\Local\example\stable\jdk\lib\modules
...

然后是第三个：

...
[14.578s][7248][debug][class,preorder          ] java.lang.InheritableThreadLocal source: C:\Users\example\AppData\Local\example\stable\jdk\lib\modules
[14.578s][7248][info ][class,load              ] java.lang.InheritableThreadLocal source: jrt:/java.base
[14.578s][7248][debug][class,load              ]  klass: 0x0000000100124740 super: 0x0000000100021a18 loader: [loader data: 0x0000000002882bd0 of 'bootstrap'] bytes: 1338 checksum: 8013ed55
[14.578s][7248][debug][class,resolve           ] java.lang.InheritableThreadLocal java.lang.ThreadLocal (super)
[14.578s][7248][debug][jit,compilation         ]  699       3       java.lang.ThreadLocal::get (38 bytes)   made not entrant
[14.578s][7248][debug][vmthread                ] Adding VM operation: HandshakeAllThreads
[14.578s][6708][debug][vmthread                ] Evaluating non-safepoint VM operation: HandshakeAllThreads
[14.578s][6708][debug][vmoperation             ] begin VM_Operation (0x000000000203d228): HandshakeAllThreads, mode: no safepoint, requested by thread 0x000000000286d800
[14.578s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026b0800, is_vm_thread: true, completed in 1600 ns
[14.578s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026bb800, is_vm_thread: true, completed in 900 ns
[14.578s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026ef800, is_vm_thread: true, completed in 100 ns
[14.578s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026f0800, is_vm_thread: true, completed in 100 ns
[14.578s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026f1800, is_vm_thread: true, completed in 100 ns
[14.578s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x00000000026f4800, is_vm_thread: true, completed in 0 ns
[14.578s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x0000000002768800, is_vm_thread: true, completed in 0 ns
[14.578s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x000000000276e000, is_vm_thread: true, completed in 0 ns
[14.578s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x0000000017268800, is_vm_thread: true, completed in 0 ns
[14.579s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x000000001727e800, is_vm_thread: true, completed in 900 ns

# no log until 21.455s

[21.455s][6708][debug][handshake,task          ] Operation: Deoptimize for thread 0x000000000286d800, is_vm_thread: true, completed in 12100 ns
[21.455s][6708][info ][handshake               ] Handshake "Deoptimize", Targeted threads: 11, Executed by targeted threads: 0, Total completion time: 6876829000 ns
[21.455s][6708][debug][vmoperation             ] end VM_Operation (0x000000000203d228): HandshakeAllThreads, mode: no safepoint, requested by thread 0x000000000286d800
[21.455s][7248][debug][class,resolve           ] sun.security.jca.Providers java.lang.InheritableThreadLocal Providers.java:39
[21.455s][7248][info ][class,init              ] 1251 Initializing 'java/lang/InheritableThreadLocal'(no method) (0x0000000100124740)
[21.455s][7248][debug][class,resolve           ] java.lang.InheritableThreadLocal java.lang.ThreadLocal InheritableThreadLocal.java:57
[21.456s][7248][debug][class,preorder          ] sun.security.jca.ProviderList source: C:\Users\example\AppData\Local\example\stable\jdk\lib\modules
[21.456s][7248][info ][class,load              ] sun.security.jca.ProviderList source: jrt:/java.base
[21.456s][7248][debug][class,load              ]  klass: 0x00000001001249a8 super: 0x0000000100001080 loader: [loader data: 0x0000000002882bd0 of 'bootstrap'] bytes: 11522 checksum: bdc239d2
[21.456s][7248][debug][class,resolve           ] sun.security.jca.ProviderList java.lang.Object (super)
...

以下两行似乎很有趣：

[11.783s][6708][info ][handshake               ] Handshake "Deoptimize", Targeted threads: 11, Executed by targeted threads: 0, Total completion time: 5536442500 ns
[21.455s][6708][info ][handshake               ] Handshake "Deoptimize", Targeted threads: 11, Executed by targeted threads: 0, Total completion time: 6876829000 ns

这些握手需要5.5秒和6.8秒，这正常吗？

我遇到了与以下命令一起运行的update4j演示应用程序（与我们的应用程序完全无关）的相同减速（和类似的日志）：

Z:\swing>\jdk-14\bin\java -Xlog:all=debug:file=app.txt:uptime,tid,level,tags:filecount=50 \
    -jar update4j-1.4.5.jar --remote http://docs.update4j.org/demo/setup.xml

我应该寻找什么来使我们的应用在单CPU Windows 10设置上再次更快？我可以通过更改应用程序中的某些内容或添加JVM参数来解决此问题吗？

这是JDK错误吗，我应该报告它吗？

更新2020-04-25：

据我所知，日志文件还包含GC日志。以下是第一个 GC 日志：

$ cat app.txt.00 | grep "\[gc"
[0.016s][7248][debug][gc,heap          ] Minimum heap 8388608  Initial heap 60817408  Maximum heap 1073741824
[0.017s][7248][info ][gc,heap,coops    ] Heap address: 0x00000000c0000000, size: 1024 MB, Compressed Oops mode: 32-bit
[0.018s][7248][info ][gc               ] Using Serial
[22.863s][6708][info ][gc,start                ] GC(0) Pause Young (Allocation Failure)
[22.863s][6708][debug][gc,heap                 ] GC(0) Heap before GC invocations=0 (full 0): def new generation   total 17856K, used 15936K [0x00000000c0000000, 0x00000000c1350000, 0x00000000d5550000)
...

不幸的是，它似乎并不相关，因为它在第三次暂停后开始。

更新2020-04-26：

使用OpenJDK 14，应用程序在我的（单CPU）VirtualBox机器（在i7-6600U CPU上运行）中使用100%的CPU。虚拟机具有 3，5 GB RAM。根据任务管理器，40%+是免费的，磁盘活动是0%（我猜这意味着没有交换）。向虚拟机添加另一个 CPU（并为物理机启用超线程）使应用程序再次足够快。我只是想知道，在JDK开发过程中，在（罕见的）单CPU机器上损失性能以使JVM在多核/超线程CPU上更快，这是故意的权衡吗？

答案 1

TL;DR：这是一个以 JDK-8244340 为归档的 OpenJDK 回归，已在 JDK 15 Build 24 （2020/5/20）中修复。

我没有这样做，但我可以用一个简单的你好世界重现这个问题：

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello world");
    }
}

我用了这两个批处理文件：

main-1cpu.bat，这会将进程限制为只有一个 CPU：java

c:\windows\system32\cmd.exe /C start /affinity 1 \
    \jdk-14\bin\java \
    -Xlog:all=trace:file=app-1cpu.txt:uptime,tid,level,tags:filecount=50 \
    Main

main-full.bat，则该进程可以使用两个 CPU：java

c:\windows\system32\cmd.exe /C start /affinity FF \
    \jdk-14\bin\java \
    -Xlog:all=trace:file=app-full.txt:uptime,tid,level,tags:filecount=50 \
    Main

（不同之处在于日志文件的值和名称。为了便于阅读，我已经包装了它，但用包装可能不适用于Windows。affinity\

在VirtualBox（带有两个CPU）中的Windows 10 x64上的一些测量结果：

PS Z:\main> Measure-Command { .\main-1cpu.bat }

...    
TotalSeconds      : 7.0203455
...


PS Z:\main> Measure-Command { .\main-full.bat }

...
TotalSeconds      : 1.5751352
...


PS Z:\main> Measure-Command { .\main-full.bat }

...
TotalSeconds      : 1.5585384
...


PS Z:\main> Measure-Command { .\main-1cpu.bat }

...
TotalSeconds      : 23.6482685
...

生成的跟踪日志包含您可以在问题中看到的类似暂停。

在没有跟踪日志的情况下运行速度更快，但单CPU和双CPU版本之间的差异仍然很明显：~4-7秒与~400毫秒。Main

我已将此发现发送到热点dev@openjdk邮件列表，那里的开发人员确认这是JDK可以更好地处理的事情。您也可以在线程中找到假定的修复程序。另一个关于热点运行时回归的线程dev@。JIRA 修复问题：JDK-8244340

答案 2

根据我的经验，JDK的性能问题主要与以下问题之一有关：

JIT 编译
VM 配置（堆大小）
气相色谱算法
JVM/JDK 中的更改会破坏已知运行良好的应用程序
（哦，我忘了提到类加载...）

如果您只使用OpenJDK11以来的默认JVM配置，也许您应该将一些更突出的选项设置为固定值，例如GC，堆大小等。

也许一些图形分析工具可以帮助跟踪您的问题。像Retrace，AppDynamics或FlightRecorder等。这些提供了有关堆，GC周期，RAM，线程，CPU负载等在给定时间的整体状态的概述，而不是日志文件可以提供的。

我是否正确地理解您的应用程序在运行的第一秒内（在 OpenJDK11 下）向日志写入了大约 30710 行？为什么它“只”在第一秒内在OpenJDK14下写了7k行？对于一个刚刚在不同JVM上启动的应用程序来说，这似乎是一个巨大的差异......例如，是否确定没有大量异常堆栈跟踪转储到日志中？

其他数字有时甚至更高，所以也许减速与异常日志记录有关？或者甚至交换，如果RAM变低？

实际上我在想，如果应用程序没有将任何内容写入日志，这是平稳运行没有问题的标志（除非它在这段时间内完全冻结）。从12-22秒（在OpenJDK14案例中）发生的事情是我更关心的事情......伐木的线路穿过屋顶...为什么？

之后，日志记录下降到大约1-2k行的历史低值...这是什么原因？？（好吧，也许是GC在第二个22点开始，并做了一个白板，解决了一些事情......？

另一件事可能是你关于“单CPU”机器的陈述。这是否也意味着“单核”（Idk，也许你的软件是在传统硬件或其他东西上量身定制的）？

“单 CPU”VM 是否在这些计算机上运行？但我认为，我对这些假设是错误的，因为现在几乎所有的CPU都是多核的......但是我会调查一个多线程问题（死锁）问题。