File: linuxproc.html

package info (click to toggle)
lg-issue23 4-2
links: PTS
area: main
in suites: potato
size: 2,360 kB
ctags: 430
sloc: makefile: 36; sh: 4
file content (1293 lines) | stat: -rw-r--r-- 41,025 bytes
parent folder | download | duplicates (4)
<HTML>
<HEAD>
   <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
   <META NAME="Generator" CONTENT="Microsoft Word 97">
   <META NAME="Template" CONTENT="C:\PROGRAM FILES\MICROSOFT OFFICE\OFFICE\html.dot">
   <META NAME="GENERATOR" CONTENT="Mozilla/4.01b6C [en] (X11; I; Linux 2.1.47 i486) [Netscape]">
   <TITLE>Processes and Process Context</TITLE>
</HEAD>
<BODY BGCOLOR="#FFFFFF" LINK="#0000FF" VLINK="#800080">
&nbsp;
<BR><FONT COLOR="#3366FF"><FONT SIZE=+3><B>A Closer Look at Processes on
the Linux Operating System</B></FONT></FONT><FONT COLOR="#3366FF"><FONT SIZE=+3></FONT></FONT>

<P><FONT SIZE=+1>&nbsp;On Linux there are a number of utilities which allow
the System Administrator to examine the status of processes and to adjust
their relative priorities or change their operational status. Some of these
capabilities can be demonstrated by examining one programme available for
the Linux OS : the Apache httpd daemon : a freely available web server.
In the following prints of screen outputs some columns have been ommitted
where they do not affect the demonstration being given.</FONT>

<P><FONT SIZE=+1>&nbsp;From the following it can be seen that the size
of the http daemon is 142699 bytes on the disk. Within the ELF file there
are 108786 bytes of code, 4796 bytes of initialised data and 19015 bytes
of uninitialiased data.</FONT>

<P><FONT SIZE=+1>&nbsp;<FONT FACE="Courier"><FONT COLOR="#0000FF">orion-1:#</FONT>
ls -l httpd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;-rwxr-x--- 1 root root 142699
Oct 5 1996 httpd*</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;<FONT COLOR="#0000FF">orion-1:#</FONT>
size httpd</FONT></FONT>
<CENTER><TABLE BORDER=0 CELLSPACING=0 CELLPADDING=7 WIDTH="451" >
<TR>
<TD VALIGN=TOP WIDTH="16%"><FONT FACE="Courier"><FONT SIZE=+1>text</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="15%"><FONT FACE="Courier"><FONT SIZE=+1>Data</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="15%"><FONT FACE="Courier"><FONT SIZE=+1>bss</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="17%"><FONT FACE="Courier"><FONT SIZE=+1>dec</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="15%"><FONT FACE="Courier"><FONT SIZE=+1>hex</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="23%"><FONT FACE="Courier"><FONT SIZE=+1>filename</FONT></FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="16%"><FONT FACE="Courier"><FONT SIZE=+1>108786&nbsp;</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="15%"><FONT FACE="Courier"><FONT SIZE=+1>4796&nbsp;</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="15%"><FONT FACE="Courier"><FONT SIZE=+1>19015&nbsp;</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="17%"><FONT FACE="Courier"><FONT SIZE=+1>132597&nbsp;</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="15%"><FONT FACE="Courier"><FONT SIZE=+1>205f5&nbsp;</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="23%"><FONT FACE="Courier"><FONT SIZE=+1>httpd</FONT></FONT></TD>
</TR>
</TABLE></CENTER>
<FONT SIZE=+1>Performing an object dump of the file shows that the code
section is offset within the file and starts at hexadecimal address 0x1ce0,
read only data starts at 0x16238, other data at 0x1a9e8 and uninitialised
data at 0x1bcb0. There is a table of debugging symbols at 0x1bcb0 :</FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;<FONT COLOR="#0000FF">orion-1:#</FONT>
objdump --headers httpd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>httpd: file format elf32-i386</FONT></FONT>

<P><FONT SIZE=+1><FONT FACE="Courier">&nbsp;Sections: </FONT>&lt; Some
sections excluded for clarity ></FONT>
<DIR>
<DIR><FONT FACE="Courier"><FONT SIZE=+1>Idx Name Size VMA LMA File off
Algn</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>0 .interp 00000013 080000d0 080000d0
000000d4 2**0</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>CONTENTS, ALLOC, LOAD, READONLY,
DATA</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>8 .text 00014544 08001ce0 08001ce0
00001ce0 2**4</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>CONTENTS, ALLOC, LOAD, READONLY,
CODE</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>10 .rodata 000047ac 08016238 08016238
00016238 2**2</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>CONTENTS, ALLOC, LOAD, READONLY,
DATA</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>11 .data 00001050 0801b9e8 0801b9e8
0001a9e8 2**2</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>CONTENTS, ALLOC, LOAD, DATA</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>16 .bss 00004a47 0801ccb0 0801ccb0
0001bcb0 2**4</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>ALLOC</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>17 .stab 000004f8 00000000 00000000
0001bcb0 2**2</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>CONTENTS, READONLY, DEBUGGING</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;</FONT></FONT></DIR>
</DIR>
<FONT SIZE=+1>The http daemon utilises functions from the standard 'C'
library, linked as a dynamic linked library (the 'so' stands for 'shared
object') :</FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;<FONT COLOR="#0000FF">orion-1:#</FONT>
ldd -r httpd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp; libc.so.5 => /usr/local/lib/libc.so.5
(0x4000a0)</FONT></FONT>

<P><FONT SIZE=+1>The daemon is started at system boot time and was sleeping
(S) when its status was checked, it is consuming very little CPU time :</FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;<FONT COLOR="#0000FF">orion-1:#</FONT>
ps -fc | grep httpd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;PID TTY STAT TIME COMMAND</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>90 ? S 0:00 httpd</FONT></FONT>

<P><FONT SIZE=+1>&nbsp;A printout of the tree of all processes running
on the computer and their interrelationships shows that the httpd has <FONT FACE="Courier">init</FONT>
as its parent process, this is typical of a Unix daemon process. It has
also created three child processes which it now controls, presumably to
listen for http connections.</FONT>

<P><FONT SIZE=+1>&nbsp;<FONT FACE="Courier"><FONT COLOR="#0000FF">orion-1:#</FONT>
pstree</FONT></FONT>
<DIR>
<DIR>
<DIR>
<DIR><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;init-+-4*[agetty]</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-bash--script--script--bash--script--script--bash--pstree</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-bash</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-crond</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-gpm</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-httpd--3*[httpd]</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-inetd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-kflushd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-klogd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-kswapd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-lpd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-rpc.mountd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-rpc.nfsd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-rpc.portmap</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-sendmail</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>|-syslogd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>`-update</FONT></FONT>

<P><FONT SIZE=+1>&nbsp;</FONT></DIR>
</DIR>
</DIR>
</DIR>
<FONT SIZE=+1>This is confirmed by examining a few of the processes running
in more detail. The <FONT FACE="Courier">init</FONT> process has a Process
ID (PID) of 1. It can be seen that the parent PID of the httpd is 1 as
expected.</FONT>

<P><FONT SIZE=+1>&nbsp;It can be seen that the resident memory footprint
(Resident Set Size (RSS)) of the httpd process is 528 kilobytes whereas
its overall size in virtual memory is 1012 Mb. It can be seen that the
process runs with a User ID of 0 (owned by the administrator (root)) and
that it is running at the default priority of 0 (-20 being maximum real-time
and 20 being the lowest priority). The SW&lt; status for the kernel swap
daemon (kswapd) process shows that it is sleeping, has no resident pages
and has a priority less than 0.</FONT>

<P><FONT SIZE=+1>&nbsp;<FONT FACE="Courier"><FONT COLOR="#0000FF">orion-1:#</FONT>
ps -cl1,2,3,90</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;F UID PID PPID PRI NI SIZE
RSS WCHAN STAT TTY TIME COMMAND</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>100 0 1 0 0 0 844 328 c01115c9 S
? 0:03 init [5]</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>40 0 2 1 0 0 0 0 c0111a38 SW ? 0:00
(kflushd)</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>40 0 3 1 -12 -12 0 0 c0111a38 SW&lt;
? 0:00 (kswapd)</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>140 0 90 1 0 0 1012 528 c0119272
S ? 0:00 httpd</FONT></FONT>

<P><FONT SIZE=+1>&nbsp;Looking at the virtual memory performances of the
process it can be seen that the httpd has had 23 major page faults where
a page fault represents an action to load a page of text from disk or buffer
cache. The text (code) resident set size (TRS) is 24 kilobytes which suggests
a code page size of 1024 bytes when viewed in association with the page
fault number. The Data Resident Size is 108 kilobytes, giving a total SIZE
of 132 kilobytes. The process shares 115 kilobytes with other processes
(this may represent the standard 'C' shared library).</FONT>

<P><FONT SIZE=+1>&nbsp;<FONT FACE="Courier"><FONT COLOR="#0000FF">orion-1:#</FONT>
ps -cmp1,2,3,90</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;</FONT></FONT>
<TABLE BORDER=0 CELLSPACING=0 CELLPADDING=7 WIDTH="500" >
<TR>
<TD VALIGN=TOP WIDTH="8%"><FONT SIZE=+1>PID</FONT></TD>

<TD VALIGN=TOP WIDTH="9%"><FONT SIZE=+1>MAJFLT</FONT></TD>

<TD VALIGN=TOP WIDTH="8%"><FONT SIZE=+1>MINFLT</FONT></TD>

<TD VALIGN=TOP WIDTH="9%"><FONT SIZE=+1>TRS</FONT></TD>

<TD VALIGN=TOP WIDTH="9%"><FONT SIZE=+1>DRS</FONT></TD>

<TD VALIGN=TOP WIDTH="9%"><FONT SIZE=+1>SIZE</FONT></TD>

<TD VALIGN=TOP WIDTH="11%"><FONT SIZE=+1>SWAP</FONT></TD>

<TD VALIGN=TOP WIDTH="9%"><FONT SIZE=+1>RSS</FONT></TD>

<TD VALIGN=TOP WIDTH="11%"><FONT SIZE=+1>SHRD</FONT></TD>

<TD VALIGN=TOP WIDTH="17%"><FONT SIZE=+1>COMMAND</FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT SIZE=+1>2</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="11%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="11%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="17%"><FONT SIZE=+1>kflushd</FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT SIZE=+1>3</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="11%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="11%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="17%"><FONT SIZE=+1>kswapd</FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT SIZE=+1>1</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>206</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT SIZE=+1>49</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>5</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>77</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>82</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="11%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>82</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="11%">
<CENTER><FONT SIZE=+1>65</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="17%"><FONT SIZE=+1>init&nbsp;</FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT SIZE=+1>90</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>23</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT SIZE=+1>51</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>24</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>108</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>132</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="11%">
<CENTER><FONT SIZE=+1>0</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT SIZE=+1>132</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="11%">
<CENTER><FONT SIZE=+1>115</FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="17%"><FONT SIZE=+1>httpd&nbsp;</FONT></TD>
</TR>
</TABLE>
<FONT FACE="Courier"><FONT SIZE=+1>&nbsp;</FONT></FONT>

<P><FONT SIZE=+1>The system administrator can re-prioritise the httpd process
by changing it's NICE level. Here the priority of process 90 (httpd) is
made higher by 10. Only the administrator can change priorities in a negative
direction as shown. This prevents inexperienced users from overloading
the CPU and also protects the system from hackers.</FONT>

<P><FONT SIZE=+1>&nbsp;<FONT FACE="Courier"><FONT COLOR="#0000FF">orion-1:#</FONT>
renice -10 90</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;90: old priority 0, new priority
-10</FONT></FONT>

<P><FONT SIZE=+1>&nbsp;The new priority level can now be seen, although
on this system the httpd is idle, receiving no web access requests so it
would not consume much more CPU.</FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1><FONT COLOR="#0000FF">orion-1:#</FONT>
ps -cl</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;</FONT></FONT>
<TABLE BORDER=0 CELLSPACING=0 CELLPADDING=7 WIDTH="470" >
<TR>
<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>UID</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>PID</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="10%"><FONT FACE="Courier"><FONT SIZE=+1>PRI</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="10%"><FONT FACE="Courier"><FONT SIZE=+1>PPID</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>NI</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="10%"><FONT FACE="Courier"><FONT SIZE=+1>SIZE</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>RSS</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>STAT</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="10%"><FONT FACE="Courier"><FONT SIZE=+1>TIME</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="20%"><FONT FACE="Courier"><FONT SIZE=+1>COMMAND</FONT></FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>1</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>844</FONT></FONT></DIV>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>328</FONT></FONT></DIV>
</TD>

<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>S</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="10%"><FONT FACE="Courier"><FONT SIZE=+1>0:03</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="20%"><FONT FACE="Courier"><FONT SIZE=+1>init [5]</FONT></FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>2</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>1</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></DIV>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></DIV>
</TD>

<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>SW</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="10%"><FONT FACE="Courier"><FONT SIZE=+1>0:00</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="20%"><FONT FACE="Courier"><FONT SIZE=+1>(kflushd)</FONT></FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>3</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>-12</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>1</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>-12</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></DIV>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></DIV>
</TD>

<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>SW&lt;</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="10%"><FONT FACE="Courier"><FONT SIZE=+1>0:00</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="20%"><FONT FACE="Courier"><FONT SIZE=+1>(kswapd)</FONT></FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>90</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>-10</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>1</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>-10</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="10%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>1012</FONT></FONT></DIV>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>528</FONT></FONT></DIV>
</TD>

<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>S &lt;</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="10%"><FONT FACE="Courier"><FONT SIZE=+1>0:00</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="20%"><FONT FACE="Courier"><FONT SIZE=+1>httpd</FONT></FONT></TD>
</TR>
</TABLE>
<FONT SIZE=+1>&nbsp;</FONT>

<P><FONT SIZE=+1>The system is now loaded somewhat by running some CPU
intensive shell scripts. The virtual memory statistics of the computer
are examined every 5 seconds for five iterations.</FONT>

<P><FONT SIZE=+1>&nbsp;The procs field shows that on average 2 processes
are waiting for CPU run time (r) and on iteration 3 two processes are in
uninterruptable sleep. There is no swapping activity going on as the processes
are small enough to be fully resident in memory.</FONT>

<P><FONT SIZE=+1>&nbsp;There is however I/O activity as blocks of data
are brought in (bi) and sent out (bo) to I/O devices. The 'system' fields
show that many interrupts are occurring per second (in) as well as many
context switches (cs). The first iteration gives the average history since
the last system reboot, whereas the subsequent four readings are for time
now. It can be seen that the CPU is never idle (id) and is spending around
35% of its time in user mode and 65% of its time performing privileged
operations in system mode.</FONT>

<P><FONT SIZE=+1>&nbsp;This report is consistent with the known operations
being performed : I/O intensive disk reads : the Linux 'find' command searching
the disk.</FONT>

<P><FONT SIZE=+1>&nbsp;<FONT FACE="Courier"><FONT COLOR="#0000FF">orion-1:#</FONT>
vmstat 5 5</FONT></FONT>
<TABLE BORDER=0 CELLSPACING=0 CELLPADDING=7 WIDTH="536" >
<TR>
<TD VALIGN=TOP COLSPAN="3" WIDTH="10%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>procs</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="4" WIDTH="24%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>memory</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="3" WIDTH="13%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>swap</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="3" WIDTH="12%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>io</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="3" WIDTH="20%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>system</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="3" WIDTH="22%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>cpu</FONT></FONT></CENTER>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="3%"><FONT FACE="Courier"><FONT SIZE=+1>r</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="4%"><FONT FACE="Courier"><FONT SIZE=+1>b</FONT></FONT></TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%"><FONT FACE="Courier"><FONT SIZE=+1>w</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="9%"><FONT FACE="Courier"><FONT SIZE=+1>swpd</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="9%"><FONT FACE="Courier"><FONT SIZE=+1>free</FONT></FONT></TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="6%"><FONT FACE="Courier"><FONT SIZE=+1>buf</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>si</FONT></FONT></TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%"><FONT FACE="Courier"><FONT SIZE=+1>so</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="7%"><FONT FACE="Courier"><FONT SIZE=+1>bi</FONT></FONT></TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%"><FONT FACE="Courier"><FONT SIZE=+1>bo</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="9%"><FONT FACE="Courier"><FONT SIZE=+1>in</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="8%"><FONT FACE="Courier"><FONT SIZE=+1>cs</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="7%"><FONT FACE="Courier"><FONT SIZE=+1>us</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="7%"><FONT FACE="Courier"><FONT SIZE=+1>sy</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="7%"><FONT FACE="Courier"><FONT SIZE=+1>id</FONT></FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="3%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>2</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="4%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="6%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>10</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>8</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>133</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>34</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>6</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>8</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>86</FONT></FONT></CENTER>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="3%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>2</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="4%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="6%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>614</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>11</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>737</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>1234</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>32</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>68</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="3%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>1</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="4%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>2</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="6%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>100</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%"><FONT FACE="Courier"><FONT SIZE=+1>129</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>435</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>366</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>40</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>60</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="3%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>2</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="4%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="6%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>202</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>26</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>375</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>455</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>33</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>67</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="3%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>2</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="4%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="6%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>230</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP COLSPAN="2" WIDTH="5%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="9%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>331</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="8%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>472</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>31</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>69</FONT></FONT></CENTER>
</TD>

<TD VALIGN=TOP WIDTH="7%">
<CENTER><FONT FACE="Courier"><FONT SIZE=+1>0</FONT></FONT></CENTER>
</TD>
</TR>
</TABLE>
<FONT FACE="Courier"><FONT SIZE=+1>&nbsp;</FONT></FONT>

<P><FONT SIZE=+1>&nbsp;It is possible to probe the Linux kernel and find
which operations are consuming the most CPU load. When this is done it
is seen that the kernel is spending most of it's time dealing with the
directory cache, file system and writing to the console. The system scheduling
process is only the twentieth most active process on the list.</FONT>

<P><FONT SIZE=+1>&nbsp;To be able to read the profiling information from
the kernel it must first be compiled with profiling enabled.</FONT>

<P><FONT SIZE=+1>&nbsp;<FONT FACE="Courier"><FONT COLOR="#0000FF">orion-1:#</FONT>
readprofile | sort -nr | head -20</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>&nbsp;</FONT></FONT>
<TABLE BORDER=0 CELLSPACING=0 CELLPADDING=7 WIDTH="415" >
<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>CLK_TCK</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>Function</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%"><FONT FACE="Courier"><FONT SIZE=+1>Normalised
load</FONT></FONT></TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>67649</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>total</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>0.0858</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>7796</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>d_lookup</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>54.1389</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>5425</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>ext2_readdir</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>3.5319</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>5034</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>scrup</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>7.8168</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>4573</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>filldir</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>14.8474</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>4481</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>find_inode</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>86.1731</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>2849</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>ext2_check_dir_entry</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>15.8278</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>2581</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>getname</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>7.9660</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1885</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>getblk</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>2.2440</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1665</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>sys_newlstat</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>6.8238</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1546</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>lookup_dentry</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>5.1533</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1542</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>do_con_write</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>0.3119</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1425</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>get_hash_table</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>9.6284</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1422</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>cp_new_stat</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>4.5577</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1323</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>__namei</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>10.3359</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1270</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>system_call</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>19.8438</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1231</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>ext2_getblk</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>2.2140</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1084</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>raw_scan_sector</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>1.8951</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>1077</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>sys_getdents</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>3.0597</FONT></FONT></DIV>
</TD>
</TR>

<TR>
<TD VALIGN=TOP WIDTH="35%"><FONT FACE="Courier"><FONT SIZE=+1>973</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="33%"><FONT FACE="Courier"><FONT SIZE=+1>schedule</FONT></FONT></TD>

<TD VALIGN=TOP WIDTH="32%">
<DIV ALIGN=right><FONT FACE="Courier"><FONT SIZE=+1>1.2102</FONT></FONT></DIV>
</TD>
</TR>
</TABLE>
<FONT SIZE=+1>&nbsp;</FONT>

<P><FONT SIZE=+1>The Linux 'ps' command takes its information from the
/proc virtual-file system (VFS) which is a disk image of the process structures
as controlled by the kernel. Note that the VFS is a direct mirror of the
kernel data structures and does not actually reside on disk, although it
appears to do so when acessed with normal Linux commands.</FONT>

<P><FONT SIZE=+1>Looking directly at the httpd process in the /proc file
system, all of the information given by the administrative tools can be
obtained, though often in a less user friendly format. The following is
a direct dump of the httpd <FONT FACE="Courier">status</FONT> table, with
comments added for explanation :</FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1><FONT COLOR="#0000FF">orion-1:#</FONT>
cat /proc/90/status</FONT></FONT>
<DIR>
<DIR><FONT FACE="Courier"><FONT SIZE=+1>Name: httpd</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>State: S (sleeping)</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>Pid: 90 # Process ID</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>PPid: 1 # Parent Process (init)</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>Uid: 0 0 0 0 # User ID (root)</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>Gid: 65535 65535 65535 65535 # Group
ID</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>VmSize: 1012 kB # Total virtual memory</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>VmLck: 0 kB # Total locked</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>VmRSS: 512 kB # Text Resident Set
Size</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>VmData: 276 kB # Virtual Memory Data
size</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>VmStk: 20 kB # Stack size</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>VmExe: 108 kB # Executable</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>VmLib: 576 kB # Library</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>SigPnd: 00000000 # Signals pending</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>SigBlk: 00000000 # Signals blocked</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>SigIgn: 80000000 # Signals ignored</FONT></FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1>SigCgt: 00006441 # Signals caught</FONT></FONT></DIR>
</DIR>
<FONT SIZE=+1>&nbsp;</FONT>

<P><FONT SIZE=+1>The following are all the signals recognised by the Linux
operating system, they are enumerated starting at zero (i.e. SIGHUP is
0, SIGKILL is 9, etc) :</FONT>

<P><FONT FACE="Courier"><FONT SIZE=+1><FONT COLOR="#0000FF">orion-1:#</FONT>
fuser -l</FONT></FONT>
<DIR>
<DIR><FONT FACE="Courier"><FONT SIZE=+1>HUP INT QUIT ILL TRAP ABRT IOT
BUS FPE KILL USR1 SEGV USR2 PIPE ALRM TERM STKFLT CHLD CONT STOP TSTP TTIN
TTOU URG XCPU XFSZ VTALRM PROF WINCH IO PWR UNUSED</FONT></FONT><FONT FACE="Courier"><FONT SIZE=+1></FONT></FONT>
<DIV ALIGN=right><A HREF="ipc.html"><IMG SRC="../gx/flower/cyan_lef.gif" BORDER=0 HEIGHT=31 WIDTH=31></A><A HREF="page1.html"><IMG SRC="../gx/flower/cyan_up.gif" BORDER=0 HEIGHT=31 WIDTH=31></A><A HREF="books.html"><IMG SRC="../gx/flower/cyan_rig.gif" BORDER=0 HEIGHT=31 WIDTH=31></A></DIV>
<FONT FACE="Courier"><FONT SIZE=+1></FONT></FONT>&nbsp;
<BR><FONT FACE="Courier"><FONT SIZE=+1></FONT></FONT>&nbsp;</DIR>
</DIR>

</BODY>
</HTML>