linux - 使用 `ps -T -p [pid]` 时如何获取整个线程名称

Question

ps -T -p [pid] 和 top -H -p [pid] 只能显示前 15 个字符，如 http-nio-8080 -e，但我想获取整个线程名称，如http-nio-8080-exec-9，我该怎么办？谢谢!

例如:

[root@localhost ~]# ps -T -p 2251
  PID  SPID TTY          TIME CMD
 2251  2251 ?        00:00:00 java
 2251  2808 ?        00:00:03 java
 2251  2821 ?        00:00:00 VM Thread
 2251  2822 ?        00:00:00 Reference Handl
 2251  2823 ?        00:00:00 Finalizer
 2251  2824 ?        00:00:00 Signal Dispatch
 2251  2825 ?        00:00:02 C2 CompilerThre
 2251  2832 ?        00:00:02 C1 CompilerThre
 2251  2835 ?        00:00:00 Sweeper thread
 2251  2851 ?        00:00:00 Service Thread
 2251  2866 ?        00:00:00 VM Periodic Tas
 2251  2867 ?        00:00:00 Common-Cleaner
 2251  6518 ?        00:00:00 Catalina-utilit
 2251  6520 ?        00:00:00 Catalina-utilit
 2251  6531 ?        00:00:00 container-0
 2251  7370 ?        00:00:00 NioBlockingSele
 2251  7374 ?        00:00:00 http-nio-8080-e
 2251  7375 ?        00:00:00 http-nio-8080-e
 2251  7376 ?        00:00:00 http-nio-8080-e
 2251  7377 ?        00:00:00 http-nio-8080-e
 2251  7378 ?        00:00:00 http-nio-8080-e
 2251  7379 ?        00:00:00 http-nio-8080-e
 2251  7380 ?        00:00:00 http-nio-8080-e
 2251  7381 ?        00:00:00 http-nio-8080-e
 2251  7382 ?        00:00:00 http-nio-8080-e
 2251  7383 ?        00:00:00 http-nio-8080-e
 2251  7384 ?        00:00:00 http-nio-8080-C
 2251  7395 ?        00:00:00 http-nio-8080-A

和

[root@localhost ~]# top -H -p 2251
top - 12:00:38 up 15 min,  1 user,  load average: 0.06, 0.11, 0.19
Threads:  28 total,   0 running,  28 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0.0 us,  0.0 sy,  0.0 ni,100.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem :  3880412 total,  2276824 free,   903836 used,   699752 buff/cache
KiB Swap:  1581052 total,  1581052 free,        0 used.  2745864 avail Mem

  PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND
 2251 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.07 java
 2808 root      20   0 3043676 152880  14232 S  0.0  3.9   0:03.00 java
 2821 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.27 VM Thread
 2822 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 Reference Handl
 2823 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 Finalizer
 2824 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 Signal Dispatch
 2825 root      20   0 3043676 152880  14232 S  0.0  3.9   0:02.76 C2 CompilerThre
 2832 root      20   0 3043676 152880  14232 S  0.0  3.9   0:02.07 C1 CompilerThre
 2835 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.01 Sweeper thread
 2851 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 Service Thread
 2866 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.74 VM Periodic Tas
 2867 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 Common-Cleaner
 6518 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.02 Catalina-utilit
 6520 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.12 Catalina-utilit
 6531 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 container-0
 7370 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.05 NioBlockingSele
 7374 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.14 http-nio-8080-e
 7375 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7376 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.03 http-nio-8080-e
 7377 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7378 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7379 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7380 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7381 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7382 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7383 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-e
 7384 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.06 http-nio-8080-C
 7395 root      20   0 3043676 152880  14232 S  0.0  3.9   0:00.00 http-nio-8080-A

它只能显示前 15 个字符，如 http-nio-8080-e，我想获取整个线程名称，如 http-nio-8080-exec-9，我该怎么办？

"http-nio-8080-exec-9" #25 daemon prio=5 os_prio=0 cpu=0.13ms elapsed=1013.48s tid=0x00007fc0708d9000 nid=0x1f waiting on condition  [0x00007fc0506b1000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@11.0.2/Native Method)
        - parking to wait for  <0x00000000c5c22c20> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@11.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@11.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@11.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@11.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@11.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@11.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@11.0.2/Thread.java:834)

Answer 1

线程名称长度限制为 16 个字符(包括终止空字节 \0)。如果包括 \0 在内的长度超过 16 个字节，则字符串会在存储前被截断。

参见 pthread_setname_np和 proc.5 -> 找到 /proc/[pid]/task/[tid]/comm。

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