影响程序的资源一般而言分为4个：CPU、内存、IO、网络。本文着重讲解一下在linux系统下，如何查看高CPU占用率的进程，线程。
编写python代码模拟真实场景
#-*- coding:utf-8 -*-
import time, threading
#测试线程的个数
num = 500
def loop():
print 'thread %s is running...' % threading.current_thread().name
k = 0
while k < 500:
k += 1
time.sleep(1)
def special():
print 'thread %s is running...' % threading.current_thread().name
while True:
pass
#启动一些普通线程
for i in range(num):
t = threading.Thread(target=loop, name='normal-' + str(i))
t.start()
t = threading.Thread(target=special, name='special')
t.start()
问题排查时使用的命令
如何确定高cpu消耗的进程
命令1：top
[root@VM_0_2_centos ~]# top
top - 14:17:48 up 182 days, 16:55, 4 users, load average: 0.67, 0.52, 0.35
Tasks: 197 total, 1 running, 196 sleeping, 0 stopped, 0 zombie
%Cpu(s): 98.3 us, 1.7 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 1883616 total, 70996 free, 1452144 used, 360476 buff/cache
KiB Swap: 0 total, 0 free, 0 used. 227156 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
12282 root 20 0 4766756 10940 2116 S 95.7 0.6 0:06.04 python2
4501 root 20 0 222060 83480 2084 S 2.7 4.4 12:18.02 YDService
11671 root 20 0 1997604 56264 760 S 0.7 3.0 220:44.13 java
15259 root 20 0 742296 13476 1488 S 0.7 0.7 559:54.71 barad_agent
15587 root 20 0 203224 15088 584 S 0.3 0.8 17:22.58 supervisord
24216 zabbix 20 0 150312 1580 124 S 0.3 0.1 3:42.66 zabbix_server
32639 mysql 20 0 1195728 404816 3368 S 0.3 21.5 185:39.43 mysqld
1 root 20 0 190864 2660 1272 S 0.0 0.1 21:27.73 systemd
2 root 20 0 0 0 0 S 0.0 0.0 0:01.30 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 8:30.35 ksoftirqd/0
5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H
7 root rt 0 0 0 0 S 0.0 0.0 0:00.01 migration/0
8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcu_bh
9 root 20 0 0 0 0 S 0.0 0.0 58:24.59 rcu_sched
10 root rt 0 0 0 0 S 0.0 0.0 1:25.38 watchdog/0
命令2：用ps -eo pid,pcpu | sort -n -k 2 （当然，可以tail一下）
提示：按第2列正序排列
[root@VM_0_2_centos ~]# ps -eo pid,pcpu | sort -n -k 2 | tail
99 0.0
PID %CPU
11555 0.1
4501 0.1
707 0.1
10177 0.2
15259 0.3
11671 0.4
32639 0.4
12282 97.2
如何确定高cpu消耗的线程
命令1：top -H
[root@VM_0_2_centos ~]# top -H
top - 14:21:38 up 182 days, 16:59, 4 users, load average: 50.62, 22.48, 8.84
Threads: 923 total, 2 running, 921 sleeping, 0 stopped, 0 zombie
%Cpu(s): 97.4 us, 2.6 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 1883616 total, 78292 free, 1452984 used, 352340 buff/cache
KiB Swap: 0 total, 0 free, 0 used. 226120 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
12793 root 20 0 4766756 10940 2116 R 95.0 0.6 3:47.29 python2
25 root 20 0 0 0 0 S 0.3 0.0 5:51.00 kswapd0
4516 root 20 0 222108 83528 2096 S 0.3 4.4 0:25.31 YDService
11839 root 20 0 1997604 56264 760 S 0.3 3.0 159:24.41 java
13799 root 20 0 158600 3120 1592 R 0.3 0.2 0:00.03 top
15258 root 20 0 158196 8676 1356 S 0.3 0.5 105:26.68 barad_agent
32651 mysql 20 0 1195728 404816 3368 S 0.3 21.5 2:34.47 mysqld
32658 mysql 20 0 1195728 404816 3368 S 0.3 21.5 7:10.84 mysqld
1 root 20 0 190864 2660 1272 S 0.0 0.1 21:27.74 systemd
2 root 20 0 0 0 0 S 0.0 0.0 0:01.30 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 8:30.36 ksoftirqd/0
5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H
7 root rt 0 0 0 0 S 0.0 0.0 0:00.01 migration/0
8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcu_bh
9 root 20 0 0 0 0 S 0.0 0.0 58:24.67 rcu_sched
10 root rt 0 0 0 0 S 0.0 0.0 1:25.38 watchdog/0
12 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kdevtmpfs
13 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 netns
命令2：ps H -eo pid,tid,pcpu | sort -n -k 3
提示：按第3列正序排列
[root@VM_0_2_centos ~]# ps H -eo pid,tid,pcpu | sort -n -k 3 | tail
892 892 0.0
895 895 0.0
9156 9156 0.0
9 9 0.0
99 99 0.0
PID TID %CPU
15259 15282 0.1
707 707 0.1
11671 11839 0.2
12282 12793 96.1
进程号 线程号 cpu占用率
假如我知道高cpu消耗的进程号是多少了，查看它的线程信息的方法为
命令1：pstree -p pid
[root@VM_0_2_centos ~]# pstree -p 12282
python2(12282)-+-{python2}(12283)
|-{python2}(12284)
|-{python2}(12285)
|-{python2}(12286)
|-{python2}(12287)
|-{python2}(12288)
|-{python2}(12289)
|-{python2}(12290)
|-{python2}(12291)
|-{python2}(12292)
命令2：查看线程的详细信息：cat /proc/进程号/task/线程号/status
[root@VM_0_2_centos ~]# cat /proc/12282/task/12793/status
Name: python2
Umask: 0022
State: R (running)
Tgid: 12282
Ngid: 0
Pid: 12793
PPid: 3248
TracerPid: 0
Uid: 0 0 0 0
Gid: 0 0 0 0
FDSize: 256
Groups: 0
VmPeak: 4766756 kB
VmSize: 701540 kB
VmLck: 0 kB
VmPin: 0 kB
VmHWM: 10968 kB
VmRSS: 8152 kB
RssAnon: 6012 kB
RssFile: 2140 kB
RssShmem: 0 kB
VmData: 570192 kB
VmStk: 132 kB
VmExe: 4 kB
VmLib: 4724 kB
VmPTE: 168 kB
VmSwap: 0 kB
Threads: 2
SigQ: 1/7283
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000001001000
SigCgt: 0000000180000002
CapInh: 0000000000000000
CapPrm: 0000001fffffffff
CapEff: 0000001fffffffff
CapBnd: 0000001fffffffff
CapAmb: 0000000000000000
Seccomp: 0
Cpus_allowed: 1
Cpus_allowed_list: 0
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: 0
nonvoluntary_ctxt_switches: 84797
命令3： top -H -p pid（实时显示）
[root@VM_0_2_centos ~]# top -H -p 12282
top - 14:26:49 up 182 days, 17:04, 4 users, load average: 4.68, 15.42, 10.21
Threads: 2 total, 1 running, 1 sleeping, 0 stopped, 0 zombie
%Cpu(s): 99.7 us, 0.3 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 1883616 total, 92920 free, 1436232 used, 354464 buff/cache
KiB Swap: 0 total, 0 free, 0 used. 244296 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
12793 root 20 0 701540 8152 2140 R 97.7 0.4 8:46.09 python2
12282 root 20 0 701540 8152 2140 S 0.0 0.4 0:00.03 python2
命令4： ps -efL | grep pid
查看该进程下所有的线程
[root@VM_0_2_centos ~]# ps -efL | grep 12282 | grep -v grep
root 12282 3248 12282 0 2 14:17 pts/2 00:00:00 python2 test.py
root 12282 3248 12793 96 2 14:17 pts/2 00:10:50 python2 test.py
结束语：
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