373個這樣處於WAITING的http-nio-8081-exec線程
"http-nio-8081-exec-385" #459 daemon prio=5 os_prio=0 tid=0x00007f4b6819a800 nid=0x674e waiting on condition [0x00007f4b2e977000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
用的AbstractQueuedSynchronizer的NonfairSync機制，看來當前線程還沒拿到鎖，阻塞等待持有鎖的線程釋放掉鎖，然后跟其他線程一起搶鎖
- parking to wait for <0x00000006c8ddb088> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:870)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2083)
從任務隊列里拿一個任務，poll如果沒拿到（任務隊列為空）則返回null，否則先加鎖，再拿任務，拿完把鎖釋放掉。鎖的話是ReentrantLock
at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:85)
at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:31)
要去獲得執行什么任務了
at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1073)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
任務線程tashThread run
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
一個處於RUNNABLE的線程，JDK的BUG ？！
"http-nio-8081-exec-386" #461 daemon prio=5 os_prio=0 tid=0x00007f4b74511000 nid=0x683f runnable [0x00007f4b2e773000]
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)
https://www.cnblogs.com/bestruggle/p/9836749.html
https://www.cnblogs.com/lcxdever/p/7481912.html
https://bugs.java.com/bugdatabase/view_bug.do?bug_id=jdk-8075484
該bug摘要信息：
JDK-8075484
SocketInputStream.socketRead0 can hang even with soTimeout set
Export
Details
Type: Bug
Status:RESOLVED
Priority: P3
Resolution: Fixed
Affects Version/s:
8u40
Fix Version/s:
9
Component/s:
core-libs
Labels:
7bpr-critical-approved CPU17_04-critical-SQE-OK CPU17_04-critical-approved noreg-hard webbug
Subcomponent: java.net
Resolved In Build: b137
CPU:
x86_64
OS:
linux
jvm調優
https://zhuanlan.zhihu.com/p/62762455
小綠書有空要看看