linux 如何查看进程的线程数？

如何查看当前进程有多少个存活线程呢？可以使用系统自动的top查看也可以使用其他的专门工具查看。下面以zookeeper的进程做例子查看线程（ID 5806）

方法1： pstree -p 5806（进程ID）。如下截图所示： [root@k8s-m1 ~]# ps -ef | grep zook root 2651 2618 0 14:35 pts/2 00:00:00 grep --color=auto zook root 5806 1 0 2019 ? 1-04:03:42 java -Dzookeeper.log.dir=. -Dzookeeper.root.logger=INFO,CONSOLE -cp /opt/zookeeper/zookeeper-3.4.6/bin/../build/classes:/opt/zookeeper/zookeeper-3.4.6/bin/../build/lib/*.jar:/opt/zookeeper/zookeeper-3.4.6/bin/../lib/slf4j-log4j12-1.6.1.jar:/opt/zookeeper/zookeeper-3.4.6/bin/../lib/slf4j-api-1.6.1.jar:/opt/zookeeper/zookeeper-3.4.6/bin/../lib/netty-3.7.0.Final.jar:/opt/zookeeper/zookeeper-3.4.6/bin/../lib/log4j-1.2.16.jar:/opt/zookeeper/zookeeper-3.4.6/bin/../lib/jline-0.9.94.jar:/opt/zookeeper/zookeeper-3.4.6/bin/../zookeeper-3.4.6.jar:/opt/zookeeper/zookeeper-3.4.6/bin/../src/java/lib/*.jar:/opt/zookeeper/zookeeper-3.4.6/bin/../conf: -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=false org.apache.zookeeper.server.quorum.QuorumPeerMain /opt/zookeeper/zookeeper-3.4.6/bin/../conf/zoo.cfg [root@k8s-m1 ~]# [root@k8s-m1 ~]# [root@k8s-m1 ~]# pstree -p 5806 java(5806)─┬─{java}(5809) ├─{java}(5810) ├─{java}(5811) ├─{java}(5812) ├─{java}(5813) ├─{java}(5814) ├─{java}(5815) ├─{java}(5816) ├─{java}(5817) ├─{java}(5818) ├─{java}(5829) ├─{java}(5830) ├─{java}(5831) ├─{java}(5832) ├─{java}(5834) ├─{java}(5835) └─{java}(5836) 方法2：查看进程的系统文件（进程ID 5806） [root@k8s-m1 ~]# cat /proc/5806/status Name: java State: S (sleeping) Tgid: 5806 Ngid: 0 Pid: 5806 PPid: 1 TracerPid: 0 Uid: 0 0 0 0 Gid: 0 0 0 0 FDSize: 256 Groups: 0 VmPeak: 2138728 kB VmSize: 2137972 kB VmLck: 0 kB VmPin: 0 kB VmHWM: 314960 kB VmRSS: 81196 kB VmData: 1946632 kB VmStk: 136 kB VmExe: 4 kB VmLib: 21068 kB VmPTE: 964 kB VmSwap: 40680 kB Threads: 18 SigQ: 0/7288 SigPnd: 0000000000000000 ShdPnd: 0000000000000000 SigBlk: 0000000000000000 SigIgn: 0000000000000003 SigCgt: 2000000181005ccc CapInh: 0000000000000000 CapPrm: 0000001fffffffff CapEff: 0000001fffffffff CapBnd: 0000001fffffffff Seccomp: 0 Cpus_allowed: 3 Cpus_allowed_list: 0-1 Mems_allowed: 00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000001 Mems_allowed_list: 0 voluntary_ctxt_switches: 56 nonvoluntary_ctxt_switches: 34

Threads: 18 就是是该进程的线程数

方法3：top -p 5806（进程ID），然后按H。 Threads: 18 total, 0 running, 18 sleeping, 0 stopped, 0 zombie %Cpu(s): 3.0 us, 1.2 sy, 0.0 ni, 95.6 id, 0.0 wa, 0.0 hi, 0.0 si, 0.2 st KiB Mem : 1884000 total, 115544 free, 631080 used, 1137376 buff/cache KiB Swap: 2097148 total, 1955724 free, 141424 used. 1007888 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 5806 root 20 0 2137972 81196 5132 S 0.0 4.3 0:00.01 java 5809 root 20 0 2137972 81196 5132 S 0.0 4.3 0:01.39 java 5810 root 20 0 2137972 81196 5132 S 0.0 4.3 4:30.45 java 5811 root 20 0 2137972 81196 5132 S 0.0 4.3 4:30.16 java 5812 root 20 0 2137972 81196 5132 S 0.0 4.3 21:35.39 java 5813 root 20 0 2137972 81196 5132 S 0.0 4.3 0:00.09 java 5814 root 20 0 2137972 81196 5132 S 0.0 4.3 0:00.02 java 5815 root 20 0 2137972 81196 5132 S 0.0 4.3 0:00.00 java 5816 root 20 0 2137972 81196 5132 S 0.0 4.3 0:05.06 java 5817 root 20 0 2137972 81196 5132 S 0.0 4.3 0:05.79 java 5818 root 20 0 2137972 81196 5132 S 0.0 4.3 0:00.00 java 5829 root 20 0 2137972 81196 5132 S 0.0 4.3 0:00.00 java 5830 root 20 0 2137972 81196 5132 S 0.0 4.3 399:34.59 java 5831 root 20 0 2137972 81196 5132 S 0.0 4.3 0:02.42 java 5832 root 20 0 2137972 81196 5132 S 0.0 4.3 505:20.46 java 5834 root 20 0 2137972 81196 5132 S 0.0 4.3 13:30.68 java 5835 root 20 0 2137972 81196 5132 S 0.0 4.3 576:26.72 java 5836 root 20 0 2137972 81196 5132 S 0.0 4.3 157:57.50 java