erlang调试技术之etop

etop是erlang进程信息查看工具，类似于UNIX的top.

一、配置参数

node

The measured node.
Value: atom()
Mandatory

setcookie

Cookie to use for the etop node - must be the same as the cookie on the measured node.
Value: atom()

lines

Number of lines (processes) to display.
Value: integer()
Default: 10

interval

The time interval (in seconds) between each update of the display.
Value: integer()
Default: 5

accumulate

If true the execution time and reductions are accumulated.
Value: boolean()
Default: false

sort

Identifies what information to sort by.
Value: runtime | reductions | memory | msg_q
Default: runtime (reductions if tracing=off)

tracing

etop uses the erlang trace facility, and thus no other tracing is possible on the measured node while etop is running, unless this option is set to off. Also helpful if the etop tracing causes too high load on the measured node. With tracing off, runtime is not measured.
Value: on | off
Default: on

二、EXPORTS

start() -> ok

This function starts etop. Note that etop is preferably started with the etop and getop scripts

start(Options) -> ok

Types:

Options = [Option]

Option = {Key, Value}

Key = atom()

Value = term()

This function starts etop. Use help/0 to see a description of the possible options.

help() -> ok

This function prints the help of etop and its options.

config(Key,Value) -> Result

Types:

Result = ok | {error,Reason}

Key = lines | interval | accumulate | sort

Value = term()

This function is used to change the tool's configuration parameters during runtime. The table above indicates the allowed values for each parameter.

dump(File) -> Result

Types:

Result = ok | {error,Reason}

File = string()

This function dumps the current display to a text file.

stop() -> stop

This function terminates etop.

三、实例

1、启动etop监控远程节点

erl -sname aa -remsh remote@domain

etop:start([{output,text},{lines,10},{sort,reductions},{accumulations,true},{interval,10}]).

或者etop -sname local@domain -lines 10 -sort reductions -accumulations true -interval 10 -setcookie remotecookie -remsh remote@domain(系统shell下执行)

========================================================================================
 tiger@durin                                                               13:40:32
 Load:  cpu         0               Memory:  total        1997    binary         33
        procs     197                        processes       0    code          173
        runq      135                        atom         1002    ets            95

Pid            Name or Initial Func    Time    Reds  Memory    MsgQ Current Function
----------------------------------------------------------------------------------------
<127.23.0>     code_server                0   59585   78064       0 gen_server:loop/6   
<127.21.0>     file_server_2              0   36380   44276       0 gen_server:loop/6   
<127.2.0>      erl_prim_loader            0   27962    3740       0 erl_prim_loader:loop
<127.9.0>      kernel_sup                 0    6998    4676       0 gen_server:loop/6   
<127.17.0>     net_kernel                62    6018    3136       0 gen_server:loop/6   
<127.0.0>      init                       0    4156    4352       0 init:loop/1         
<127.16.0>     auth                       0    1765    1264       0 gen_server:loop/6   
<127.18.0>     inet_tcp_dist:accept       0     660    1416       0 prim_inet:accept0/2 
<127.5.0>      application_controll       0     569    6756       0 gen_server:loop/6   
<127.137.0>    net_kernel:do_spawn_       0     553    5840       0 dbg:do_relay_1/1    
========================================================================================

2、修改配置参数

etop:config(lines, 5)

(etop@durin)2> 
========================================================================================
 tiger@durin                                                               10:12:44
 Load:  cpu         0               Memory:  total        1859    binary         33
        procs     192                        processes       0    code          173
        runq        2                        atom         1002    ets            95

Pid            Name or Initial Func    Time    Reds  Memory    MsgQ Current Function
----------------------------------------------------------------------------------------
<127.17.0>     net_kernel               183      70    4092       0 gen_server:loop/6   
<127.335.0>    inet_tcp_dist:do_acc     141      22    1856       0 dist_util:con_loop/9
<127.19.0>     net_kernel:ticker/2      155       6    1244       0 net_kernel:ticker1/2
<127.341.0>    net_kernel:do_spawn_       0       0    5840       0 dbg:do_relay_1/1    
<127.43.0>     ddll_server                0       0    3744       0 gen_server:loop/6   
========================================================================================