检查进程的内存使用

检查单个进程内存使用

• 使用 top -p PID 可以查看单个进程的使用，然后按下 d 输入一个代表采样间隔的秒，就可以按照指定是时间刷新。

• 使用pmap可以详细输出一个进程或线程的内存映射报告

sudo pmap 34751

可以看到详细的报告

34751:   /usr/local/python/bin/python /opt/demo/bin/demo-server --config-file=/etc/demo.conf --log-config=/etc/demo-log.conf
0000000000400000      4K r-x--  /usr/local/python/bin/python2.7
0000000000600000      4K rw---  /usr/local/python/bin/python2.7
0000000000601000  10096K rw---    [ anon ]
0000000041826000      4K -----    [ anon ]
...
00007fff4bab8000     84K rw---    [ stack ]
00007fff4bb42000      4K r-x--    [ anon ]
ffffffffff600000      4K r-x--    [ anon ]
 total           192320K

其中最后输出的total字段值不是进程使用的当前内存，需要使用-x参数来输出扩展字段

-x   extended       Show the extended format.
-d   device         Show the device format.

EXTENDED AND DEVICE FORMAT FIELDS
       Address:   start address of map
       Kbytes:    size of map in kilobytes
       RSS:       resident set size in kilobytes
       Dirty:     dirty pages (both shared and private) in kilobytes
       Mode:      permissions on map: read, write, execute, shared, private (copy on write)
       Mapping:   file backing the map, or ’[ anon ]’ for allocated memory, or  ’[ stack ]’ for the program stack
       Offset:    offset into the file
       Device:    device name (major:minor)

例如 sudo pmap -x 34751 输出显示

34751:   /usr/local/python/bin/python /opt/demo/bin/demo-server --config-file=/etc/demo.conf --log-config=/etc/demo-log.conf
Address           Kbytes     RSS   Dirty Mode   Mapping
0000000000400000       4       4       0 r-x--  python2.7
0000000000600000       4       4       4 rw---  python2.7
0000000000601000   10096    9964    9964 rw---    [ anon ]
...
00007fff4bb42000       4       4       0 r-x--    [ anon ]
ffffffffff600000       4       0       0 r-x--    [ anon ]
----------------  ------  ------  ------
total kB          192320   16360   12512

pmap是从 /proc/PID/maps 和 /proc/PID/smaps 中获取的信息。

检查进程的内存使用并按照内存使用量排序

ps的参数--sort spec可以指定列进行升序和降序排列

--sort spec     specify sorting order. Sorting syntax is [+|-]key[,[+|-]key[,...]] 
                Choose a multi-letter key from the STANDARD FORMAT SPECIFIERS section. 
                The "+" is optional since default direction is increasing numerical or 
                lexicographic order. Identical to k. For example:

                ps jax --sort=uid,-ppid,+pid

例如要检查系统中进程使用内存从高到低排列

ps aux --sort -rss

检查系统进程中超过cpu阀值和memory阀值的方法

MAX_CPU=5
MAX_MEM=10
ps aux | sort -rn -k 3 | awk '$3>$MAX_CPU {ot="";i=11;while(i<=NF) {ot=ot" "$i;i++};print $3,ot}'
ps aux | sort -rn -k 4 | awk '$3>$MAX_MEM {ot="";i=11;while(i<=NF) {ot=ot" "$i;i++};print $4,ot}'

上述统计超过5%的CPU usage的进程，还存在一个缺陷，就是没有计算system，待完善。

参考

• How to find the memory consumption of a particular process in linux for every 5 seconds

• Actual memory usage of a process

• How to measure actual memory usage of an application or process?

• Understanding memory usage on Linux

• Linux process memory usage - how to sort the ps command