<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE chapter SYSTEM "chapter.dtd">
<chapter>
<header>
<copyright>
<year>2002</year><year>2013</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
</legalnotice>
<title>Erlang Top</title>
<prepared></prepared>
<docno></docno>
<date></date>
<rev></rev>
<file>etop_ug.xml</file>
</header>
<section>
<title>Introduction</title>
<p>Erlang Top, <c>etop</c> is a tool for presenting information
about erlang processes similar to the information presented by
<c>top</c> in UNIX.
</p>
</section>
<section>
<title>Output</title>
<p>The output from <c>etop</c> looks like this:</p>
<code type="none"><![CDATA[
========================================================================================
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
========================================================================================
]]></code>
<p>The header includes some system information:
</p>
<taglist>
<tag>Load</tag>
<item><c>cpu</c> is <c>Runtime/Wallclock</c>, i.e. the
percentage of time where the node has been
active, <c>procs</c> is the number of processes on the node,
and <c>runq</c> is the number of processes that are ready to
run.</item>
<tag>Memory</tag>
<item>This is the memory allocated by the node in kilo bytes.</item>
</taglist>
<p>For each process the following information is presented:
</p>
<taglist>
<tag>Time</tag>
<item>This is the runtime for the process, i.e. the actual
time the process has been scheduled in.</item>
<tag>Reds</tag>
<item>This is the number of reductions that has been executed
on the process</item>
<tag>Memory</tag>
<item>This is the size of the process in bytes, obtained by a
call to <c>process_info(Pid,memory)</c>.</item>
<tag>MsgQ</tag>
<item>This is the length of the message queue for the process.</item>
</taglist>
<note>
<p><em>Time</em> and <em>Reds</em> can be presented as
accumulated values or as values since last update.</p>
</note>
</section>
<section>
<title>Start</title>
<p>To start etop use the script
<c>etop</c> or the batch file <c>etop.bat</c>, e.g. <c>etop -node tiger@durin</c>,
</p>
</section>
<section>
<title>Configuration</title>
<p>All configuration parameters can be set at start by adding
<c>-OptName Value</c> to the command line, e.g. <c>etop -node tiger@durin -setcookie mycookie -lines 15</c>.
</p>
<p>The parameters <c>lines</c>, <c>interval</c>, <c>accumulate</c>
and <c>sort</c> can be changed during runtime by the
function <c>etop:config/2</c>.
</p>
<p>A list of all valid configuration parameters can be found in
the reference manual for <c>etop</c>.
</p>
<section>
<title>Example: Change configuration with text based presentation</title>
<code type="none"><![CDATA[
========================================================================================
tiger@durin 10:12:39
Load: cpu 0 Memory: total 1858 binary 33
procs 191 processes 0 code 173
runq 2 atom 1002 ets 95
Pid Name or Initial Func Time Reds Memory MsgQ Current Function
----------------------------------------------------------------------------------------
<127.23.0> code_server 0 60350 71176 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
<127.17.0> net_kernel 0 13808 3916 0 gen_server:loop/6
<127.9.0> kernel_sup 0 6998 4676 0 gen_server:loop/6
<127.0.0> init 0 4156 4352 0 init:loop/1
<127.18.0> inet_tcp_dist:accept 0 2196 1416 0 prim_inet:accept0/2
<127.16.0> auth 0 1893 1264 0 gen_server:loop/6
<127.43.0> ddll_server 0 582 3744 0 gen_server:loop/6
<127.5.0> application_controll 0 569 6756 0 gen_server:loop/6
======================================================================================== ]]></code>
<p><em><c>etop:config(lines,5).</c></em> <br></br>
<em><c>ok</c></em></p>
<code type="none"><![CDATA[
(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
========================================================================================
]]></code>
</section>
</section>
<section>
<title>Print to file</title>
<p>At any time, the current <c>etop</c> display can be dumped to a
text file with the function <c>etop:dump/1</c>.
</p>
</section>
<section>
<title>Stop</title>
<p>Use the function <c>etop:stop/0</c> to stop <c>etop</c>.
</p>
</section>
</chapter>