linux分析、诊断及调优的必备“杀器”

linux分析、诊断及调优的必备“杀器”
 

1、top

top - 02:06:59 up 4 days, 17:14, 2 users, load average: 0.00, 0.00, 0.00

Tasks: 62 total, 1 running, 61 sleeping, 0 stopped, 0 zombie

Cpu(s): 0.2% us, 0.3% sy, 0.0% ni, 97.8% id, 1.7% wa, 0.0% hi, 0.0% si

Mem: 515144k total, 317624k used, 197520k free, 66068k buffers

Swap: 1048120k total, 12k used, 1048108k free, 179632k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

13737 root 17 0 1760 896 1540 R 0.7 0.2 0:00.05 top

238 root 5 -10 0 0 0 S 0.3 0.0 0:01.56 reiserfs/0

1 root 16 0 588 240 444 S 0.0 0.0 0:05.70 init

2 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0

3 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0

4 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/1

5 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/1

6 root 5 -10 0 0 0 S 0.0 0.0 0:00.02 events/0

 

输出列说明：

PID：Process identification.

USER：Name of the user who owns (and perhaps started) the process.

PRI：Priority of the process. (See 1.1.4, “Process priority and nice level” on page 5 for details.)

SIZE：Amount of memory (code+data+stack) used by the process in kilobytes.

RSS：Amount of physical RAM used, in kilobytes.

SHARE：Amount of memory shared with other processes, in kilobytes.

STAT：State of the process: S=sleeping, R=running, T=stopped or traced,D=interruptible sleep, Z=zombie. 

%CPU：Share of the CPU usage (since the last screen update).

%MEM：Share of physical memory.

TIME：Total CPU time used by the process (since it was started).

COMMAND：Command line used to start the task (including parameters).

 

有用的热键：

t ：Displays summary information off and on.

m ：Displays memory information off and on.

A ：Sorts the display by top consumers of various system resources. Useful for quick identification of performance-hungry tasks on a system.

f ：Enters an interactive configuration screen for top. Helpful for setting up top for a specific task.

o ：Enables you to interactively select the ordering within top.

r ：Issues renice command.

k ：Issues kill command.

O or F：enters an interactive configuration screen for processes order.

h：displays help screen.

2、vmstat

procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----

r b swpd free buff cache si so bi bo in cs us sy id wa

0 1 0 1742264 112116 1999864 0 0 1 4 3 3 0 0 99 0

0 1 0 1742072 112208 1999772 0 0 0 2536 1258 1146 0 1 75 24

0 1 0 1741880 112260 1999720 0 0 0 2668 1235 1002 0 1 75 24

0 1 0 1741560 112308 1999932 0 0 0 2930 1240 1015 0 1 75 24

1 1 0 1741304 112344 2000416 0 0 0 2980 1238 925 0 1 75 24

0 1 0 1741176 112384 2000636 0 0 0 2968 1233 929 0 1 75 24

0 1 0 1741304 112420 2000600 0 0 0 3024 1247 925 0 1 75 24

 

输出列说明：

Process (procs) r:The number of processes waiting for runtime

                              b: The number of processes in uninterruptable sleep

Memory                swpd: The amount of virtual memory used (KB)

                              free: The amount of idle memory (KB)

                              buff: The amount of memory used as buffers (KB)

                             cache: The amount of memory used as cache (KB)

Swap                   si: Amount of memory swapped from the disk (KBps)

                             so: Amount of memory swapped to the disk (KBps)

IO                         bi: Blocks sent to a block device (blocks/s)

                             bo: Blocks received from a block device (blocks/s)

System               in: The number of interrupts per second, including the clock

                             cs: The number of context switches per second

CPU (% of total CPU time)

                             us: Time spent running non-kernel code (user time, including nice time).

                             sy: Time spent running kernel code (system time).

                             id: Time spent idle. Prior to Linux 2.5.41, this included I/O-wait time.

                             wa: Time spent waiting for IO. Prior to Linux 2.5.41, this appeared as zero.

 

有用的命令行参数：

-m:displays the memory utilization of the kernel (slabs)

-a:provides information about active and inactive memory pages

-n:displays only one header line, useful if running vmstat in sampling mode and piping the output to a file. (For example, root#vmstat –n 2 10 generates vmstat 10 times with a sampling rate of two seconds.)When used with the –p {partition} flag, vmstat also provides I/O statistics.

3、uptime

10:12:37 up 244 days, 26 min,  1 user,  load average: 10.92, 23.68, 23.64

说明：

The uptime command can be used to see how long the server has been running and how many users are logged on, as well as for a quick overview of the average load of the server.The system load average is displayed for the past 1minute, 5 minute, and 15 minute intervals.

4、ps

有用的命令选项：

-e:All processes. Identical to -A

-l:Show long format

-F:Extra full mode

-H:Forest

-L:Show threads, possibly with LWP and NLWP columns

-m:Show threads after processes

root# ps -elFL

F S UID PID PPID LWP C NLWP PRI NI ADDR SZ WCHAN RSS PSR STIME TTY TIME CMD

4 S root 1 0 1 0 1 76 0 - 457 - 552 0 Mar08 ? 00:00:01 init [3]

1 S root 2 1 2 0 1 -40 - - 0 migrat 0 0 Mar08 ? 00:00:36 [migration/0]

1 S root 3 1 3 0 1 94 19 - 0 ksofti 0 0 Mar08 ? 00:00:00 [ksoftirqd/0]

root# ps -eLF| grep -E "LWP|/usr/sbin/httpd"

UID PID PPID LWP C NLWP SZ RSS PSR STIME TTY TIME CMD

root 4504 1 4504 0 1 4313 8600 2 08:33 ? 00:00:00 /usr/sbin/httpd

apache 4507 4504 4507 0 1 4313 4236 1 08:33 ? 00:00:00 /usr/sbin/httpd

apache 4508 4504 4508 0 1 4313 4228 1 08:33 ? 00:00:00 /usr/sbin/httpd

输出列说明：

F:Process flag

S:State of the process: S=sleeping, R=running, T=stopped or traced,D=interruptable sleep, Z=zombie. 

UID:Name of the user who owns (and perhaps started) the process.

PID:Process ID number

PPID:Parent process ID number

LWP:LWP(light weight process, or thread) ID of the lwp being reported.

C:Integer value of the processor utilization percentage.(CPU usage)

NLWP:Number of lwps (threads) in the process. (alias thcount).

PRI:Priority of the process. 

NI:Niceness level (whether the process tries to be nice by adjusting the priority by the number given; see below for details).

ADDR:Process Address space (not displayed)

SZ:Amount of memory (code+data+stack) used by the process in kilobytes.

WCHAN:Name of the kernel function in which the process is sleeping, a “-” if the process is running, or a “*” if the process is multi-threaded and ps is not displaying threads.

RSS:Resident set size, the non-swapped physical memory that a task has used (in kiloBytes).

PSR:Processor that process is currently assigned to.

STIME:Time the command started.

TTY:Terminal

TIME:Total CPU time used by the process (since it was started).

CMD:Command line used to start the task (including parameters).

5、free

有用的命令参数：

-b, -k, -m, -g:Display values in bytes, kilobytes, megabytes, and gigabytes

-l:Distinguishes between low and high memory 

-c <count>:Displays the free output <count> number of times

[root@edam ~]# free -l

                 total                used               free            shared                buffers                   cached

Mem:       4154484       2381500       1772984    0                          108256                  1974344

Low:         877828        199436           678392

High:        3276656      2182064        1094592

-/+ buffers/cache:        298900           3855584

Swap:      4194296      0                       4194296