This document describes various aspects of DHCP performance,
measurements and tuning. It covers BIND 10 DHCP (codename Kea),
existing ISC DHCP4 software, perfdhcp (a DHCP performance
- measurement tool) and other related topics.</p></div></div></div><hr></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="preface"><a href="#d0e28">Preface</a></span></dt><dd><dl><dt><span class="section"><a href="#acknowledgements">Acknowledgements</a></span></dt></dl></dd><dt><span class="chapter"><a href="#intro">1. Introduction</a></span></dt><dt><span class="chapter"><a href="#dhcp4">2. ISC DHCP 4.x</a></span></dt><dt><span class="chapter"><a href="#kea">3. Kea</a></span></dt><dd><dl><dt><span class="section"><a href="#d0e54">Backend performance evaluation</a></span></dt><dt><span class="section"><a href="#mysql-backend">MySQL backend</a></span></dt><dd><dl><dt><span class="section"><a href="#d0e156">MySQL tweaks</a></span></dt></dl></dd><dt><span class="section"><a href="#sqlite-ubench">SQLite-ubench</a></span></dt><dd><dl><dt><span class="section"><a href="#sqlite-tweaks">SQLite tweaks</a></span></dt></dl></dd><dt><span class="section"><a href="#memfile-ubench">memfile-ubench</a></span></dt><dd><dl><dt><span class="section"><a href="#memfile-tweaks">memfile tweaks</a></span></dt></dl></dd><dt><span class="section"><a href="#d0e245">Performance measurements</a></span></dt><dt><span class="section"><a href="#d0e521">Possible further optimizations</a></span></dt></dl></dd><dt><span class="chapter"><a href="#perfdhcp">4. perfdhcp</a></span></dt><dd><dl><dt><span class="section"><a href="#d0e533">Purpose</a></span></dt><dt><span class="section"><a href="#
d0e538">Key features</a></span></dt><dt><span class="section"><a href="#perfdhcp-command-line">Command line options</a></span></dt><dt><span class="section"><a href="#d0e574">Running a test</a></span></dt></dl></dd></dl></div><div class="list-of-tables"><p><b>List of Tables</b></p><dl><dt>3.1. <a href="#d0e256">Synchronous results</a></dt><dt>3.2. <a href="#d0e332">Asynchronous results</a></dt><dt>3.3. <a href="#tbl-perf-results">Estimated performance</a></dt></dl></div><div class="preface" title="Preface"><div class="titlepage"><div><div><h2 class="title"><a name="d0e28"></a>Preface</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#acknowledgements">Acknowledgements</a></span></dt></dl></div><div class="section" title="Acknowledgements"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="acknowledgements"></a>Acknowledgements</h2></div></div></div><p>ISC would like to acknowledge generous support for
+ measurement tool) and other related topics.</p></div></div></div><hr></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="preface"><a href="#d0e28">Preface</a></span></dt><dd><dl><dt><span class="section"><a href="#acknowledgements">Acknowledgements</a></span></dt></dl></dd><dt><span class="chapter"><a href="#intro">1. Introduction</a></span></dt><dt><span class="chapter"><a href="#dhcp4">2. ISC DHCP 4.x</a></span></dt><dt><span class="chapter"><a href="#kea">3. Kea</a></span></dt><dd><dl><dt><span class="section"><a href="#d0e54">Backend performance evaluation</a></span></dt><dt><span class="section"><a href="#mysql-backend">MySQL backend</a></span></dt><dd><dl><dt><span class="section"><a href="#d0e156">MySQL tweaks</a></span></dt></dl></dd><dt><span class="section"><a href="#sqlite-ubench">SQLite-ubench</a></span></dt><dd><dl><dt><span class="section"><a href="#sqlite-tweaks">SQLite tweaks</a></span></dt></dl></dd><dt><span class="section"><a href="#memfile-ubench">memfile-ubench</a></span></dt><dd><dl><dt><span class="section"><a href="#memfile-tweaks">memfile tweaks</a></span></dt></dl></dd><dt><span class="section"><a href="#d0e245">Performance measurements</a></span></dt><dt><span class="section"><a href="#d0e521">Possible further optimizations</a></span></dt></dl></dd><dt><span class="chapter"><a href="#perfdhcp">4. perfdhcp</a></span></dt><dd><dl><dt><span class="section"><a href="#d0e533">Purpose</a></span></dt><dt><span class="section"><a href="#
perfdhcp-key-features">Key features</a></span></dt><dt><span class="section"><a href="#perfdhcp-command-line">Command line options</a></span></dt><dt><span class="section"><a href="#starting-perfdhcp">Starting perfdhcp</a></span></dt><dt><span class="section"><a href="#perfdhcp-commandline-examples">perfdhcp command line examples</a></span></dt><dd><dl><dt><span class="section"><a href="#perfdhcp-basic-usage">Example: basic usage</a></span></dt><dt><span class="section"><a href="#perfdhcp-rate-control">Example: rate control</a></span></dt><dt><span class="section"><a href="#perfdhcp-templates">Example: templates</a></span></dt></dl></dd></dl></dd></dl></div><div class="list-of-tables"><p><b>List of Tables</b></p><dl><dt>3.1. <a href="#d0e256">Synchronous results</a></dt><dt>3.2. <a href="#d0e332">Asynchronous results</a></dt><dt>3.3. <a href="#tbl-perf-results">Estimated performance</a></dt></dl></div><div class="preface" title="Preface"><div class="titlepage"><div><div><h2 class="title"><a name="d0e28"></a>Preface</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#acknowledgements">Acknowledgements</a></span></dt></dl></div><div class="section" title="Acknowledgements"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="acknowledgements"></a>Acknowledgements</h2></div></div></div><p>ISC would like to acknowledge generous support for
BIND 10 development of DHCPv4 and DHCPv6 components provided
by <a class="ulink" href="http://www.comcast.com/" target="_top">Comcast</a>.</p></div></div><div class="chapter" title="Chapter 1. Introduction"><div class="titlepage"><div><div><h2 class="title"><a name="intro"></a>Chapter 1. Introduction</h2></div></div></div><p>
This document is in its early stages of development. It is
Multi-threaded or multi-process benchmark may be considered in
the future. It may be somewhat difficult as only some backends
support concurrent access.
- </p></div></div><div class="chapter" title="Chapter 4. perfdhcp"><div class="titlepage"><div><div><h2 class="title"><a name="perfdhcp"></a>Chapter 4. perfdhcp</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#d0e533">Purpose</a></span></dt><dt><span class="section"><a href="#
d0e538">Key features</a></span></dt><dt><span class="section"><a href="#perfdhcp-command-line">Command line options</a></span></dt><dt><span class="section"><a href="#d0e574">Running a test</a></span></dt></dl></div><div class="section" title="Purpose"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="d0e533"></a>Purpose</h2></div></div></div><p>
+ </p></div></div><div class="chapter" title="Chapter 4. perfdhcp"><div class="titlepage"><div><div><h2 class="title"><a name="perfdhcp"></a>Chapter 4. perfdhcp</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#d0e533">Purpose</a></span></dt><dt><span class="section"><a href="#
perfdhcp-key-features">Key features</a></span></dt><dt><span class="section"><a href="#perfdhcp-command-line">Command line options</a></span></dt><dt><span class="section"><a href="#starting-perfdhcp">Starting perfdhcp</a></span></dt><dt><span class="section"><a href="#perfdhcp-commandline-examples">perfdhcp command line examples</a></span></dt><dd><dl><dt><span class="section"><a href="#perfdhcp-basic-usage">Example: basic usage</a></span></dt><dt><span class="section"><a href="#perfdhcp-rate-control">Example: rate control</a></span></dt><dt><span class="section"><a href="#perfdhcp-templates">Example: templates</a></span></dt></dl></dd></dl></div><div class="section" title="Purpose"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="d0e533"></a>Purpose</h2></div></div></div><p>
There is a growing need to evaluate performance of DHCP servers in
different traffic conditions to understand their bottle necks.
This helps to elimante bugs in existing DHCP software as well
mostly. However, the number of implemented features and parameters
exposed to the user make this tool useful for functional testing as
well.
- </p></div><div class="section" title="Key features"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="
d0e538"></a>Key features</h2></div></div></div><p>
+ </p></div><div class="section" title="Key features"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="
perfdhcp-key-features"></a>Key features</h2></div></div></div><p>
The perfdhcp exposes the number of command line parameters to
control DHCP message exchanges. Currently they fall back to
the following categories:
</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>
Rate control - control how many DHCP exchanges
are initiated within a period of time. Tool can also simulate
- best effort conditions where it attempts to start as many
- exchanges as possible.
+ best effort conditions attempting to initiate as many DHCP
+ packet exchanges within a unit of time as possible.
</p></li><li class="listitem"><p>
Test exit specifiers - control the conditions when test
completes including number of initiated exchanges, test period or
exchanges are not successfully completed.
</pre><p>
- </p></div><div class="section" title="
Running a test"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="d0e574"></a>Running a test</h2></div></div></div><p>
+ </p></div><div class="section" title="
Starting perfdhcp"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="starting-perfdhcp"></a>Starting perfdhcp</h2></div></div></div><p>
In order to run performance test at least two separate systems
have to be installed: client and server. The first one has to have
perfdhcp tool installed, the latter has to have DHCP server
impacted by the performance of VMs.
</p><p>
The DHCP operates on low port numbers (67 for DHCPv4 relays and
- 547 for DHCPv6) running perfdhcp with non-root priviliges will
+ 547 for DHCPv6). Running perfdhcp with non-root priviliges will
usually result in the error message similar to this:
</p><pre class="screen"><strong class="userinput"><code>$./perfdhcp -4 -l eth3 -r 100 all</code></strong>
Error running perfdhcp: Failed to bind socket 3 to 172.16.1.2/port=67
</pre><p>
- perfdhcp exposes '-L' command line option that
- imposes use of custom local port and the following command line will
- work:
+ perfdhcp has the '-L' command line option that
+ imposes use of custom local port. Thus the following command
+ line will work:
</p><pre class="screen"><strong class="userinput"><code>$./perfdhcp -4 -l eth3 -r 100 -L 10067 all</code></strong></pre><p>
but in the standard configuration no responses will be received
from the ISC DHCP server because server responds to default relay
port 67.
+ Alternative way to overcome this issue is to run perfdhcp as root.
</p><p>
- Alternative way to overcome the issue with lack of privileges
- to use default DHCP port number is to run perfdhcp as root.
- </p><p>
- In this section the perfdhcp command line options examples
+ Currently, perfdhcp is seen from the server perspective as relay agent.
+ This simplifies its implementation (specifically there is no need to
+ receive traffic sent to braodcast addresses). This imposes that IPv4
+ address has to be set manually on the interface that will be used to
+ communicate with the server. For example, if DHCPv4 server is listening
+ on the interface connected to 172.16.1.0 subnet, interface on client
+ machine has to have network address assigned from the same subnet
+ on one of its interfaces connected to this subnet:
+ </p><pre class="screen"><strong class="userinput"><code>#ifconfig eth3 172.16.1.2. netmask 255.255.255.0 up</code></strong></pre><p>
+ </p></div><div class="section" title="perfdhcp command line examples"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="perfdhcp-commandline-examples"></a>perfdhcp command line examples</h2></div></div></div><p>
+ In this section the perfdhcp command line examples
are presented as a quick start guide for new users. For the
detailed list of command line options refer to
<a class="xref" href="#perfdhcp-command-line" title="Command line options">the section called “Command line options”</a>.
- </p><p>
- </p><pre class="screen">
- <strong class="userinput"><code></code></strong>
- </pre><p>
- </p></div></div></div></body></html>
\ No newline at end of file
+ </p><div class="section" title="Example: basic usage"><div class="titlepage"><div><div><h3 class="title"><a name="perfdhcp-basic-usage"></a>Example: basic usage</h3></div></div></div><p>
+ If server is listening on interface with IPv4 address 172.16.1.1
+ the simpliest perfdhcp command line will look like this:
+ </p><pre class="screen"><strong class="userinput"><code>#./perfdhcp 172.16.1.1</code></strong>
+***Rate statistics***
+Rate: 206.345
+
+***Statistics for: DISCOVER-OFFER***
+sent packets: 21641
+received packets: 350
+drops: 21291
+orphans: 0
+
+min delay: 9.022 ms
+avg delay: 143.100 ms
+max delay: 259.303 ms
+std deviation: 56.074 ms
+collected packets: 30
+
+***Statistics for: REQUEST-ACK***
+sent packets: 350
+received packets: 268
+drops: 82
+orphans: 0
+
+min delay: 3.010 ms
+avg delay: 152.470 ms
+max delay: 258.634 ms
+std deviation: 56.936 ms
+collected packets: 0
+ </pre><p>
+ In this case perfdhcp will use remote address 172.16.1.1 as a
+ destination address and will use suitable local interface for
+ communication. Since, no rate control parameters have been specified
+ it will be initiating DHCP exchanges with the maximum possible
+ rate (it will try to initiate maximum number of exchanges per
+ second and count number of completed exchanged). Due to server's
+ performance constraints, many DHCP packets sent to server are likely
+ to be dropped. The performance test will be running until it is
+ not interrupted by the user (with ^C).
+ </p><p>
+ The default performance statistics reported by perfdhcp have the
+ following meaning:
+ </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>Rate - number of packet exchanges (packet sent
+ to the server and matching response received from the server)
+ completed within a second.</p></li><li class="listitem"><p>sent packets - total number of DHCP packets of
+ a specific type sent to the server.</p></li><li class="listitem"><p>received packets - total number of DHCP packets
+ of specific type received from the server.</p></li><li class="listitem"><p>drops - number of dropped packets for the
+ particular exchange. Number of dropped packets is calculated as
+ a difference between number of sent packets and number of
+ response packets received from the server. It is likely that
+ server sent the reponse but perfdhcp execution had ended before
+ reponse arrived. In such case this packet will be assumed
+ dropped.</p></li><li class="listitem"><p>orphans - number of packets that have been
+ received from the server and did not match any packet sent by
+ perfdhcp. This may occur if received packet has been sent
+ to some other host or if exchange time out has occured and
+ has been been garbage collected.</p></li><li class="listitem"><p>min delay - minimum delay that occured between
+ sending the packet to the server and receiving reponse from
+ it.</p></li><li class="listitem"><p>avg delay - average delay between sending the
+ packet of the specific type the server and receiving response
+ from it.</p></li><li class="listitem"><p>max delay - maximum delat that occured between
+ sedning the packet to the server and receiveing response from
+ it.</p></li><li class="listitem"><p>std deviation - standard deviation of delay
+ between sending the packet of a specific type to the server and
+ receiving response from it.</p></li><li class="listitem"><p>collected packets - number of garbage collected
+ sent packets. Packets may get garbage collected when waiting time
+ for server response exceeds value set with
+ -d<drop-time>.</p></li></ul></div><p>
+ </p><p>
+ perfdhcp allows to run the test using specified interface:
+ </p><pre class="screen"><strong class="userinput"><code>#./perfdhcp -l eth3</code></strong></pre><p>
+ or local address assigned to it:
+ </p><pre class="screen"><strong class="userinput"><code>#./perfdhcp -l 172.16.1.2</code></strong></pre><p>
+ </p></div><div class="section" title="Example: rate control"><div class="titlepage"><div><div><h3 class="title"><a name="perfdhcp-rate-control"></a>Example: rate control</h3></div></div></div><p>
+ In the examples above perfdhcp initiates new exchanges with best
+ effort rate. In this case many packets is expected to be dropped by the
+ server due to performance limitations. Many times it is desired to set
+ the expected (reasonable) rate and verify if generated traffic is
+ handled without packet dropes by DHCP server. The following command will
+ make perfdhcp to initiate 300 4-way exchanges per second and test will
+ last for 60 seconds:
+ </p><pre class="screen"><strong class="userinput"><code>#./perfdhcp -l eth3 -p 60 -r 300</code></strong>
+***Rate statistics***
+Rate: 256.683 exchanges/second, expected rate: 300 exchanges/second
+
+***Statistics for: DISCOVER-OFFER***
+sent packets: 17783
+received packets: 15401
+drops: 2382
+orphans: 0
+
+min delay: 0.109 ms
+avg delay: 75.756 ms
+max delay: 575.614 ms
+std deviation: 60.513 ms
+collected packets: 11
+
+***Statistics for: REQUEST-ACK***
+sent packets: 15401
+received packets: 15317
+drops: 84
+orphans: 0
+
+min delay: 0.536 ms
+avg delay: 72.072 ms
+max delay: 576.749 ms
+std deviation: 58.189 ms
+collected packets: 0
+ </pre><p>
+ Note that in this example the packet drops have been significantly
+ reduced thanks to setting reasonable rate. The non-zero number of
+ packet drops and achived rate (256/s) below expected rate (300/s)
+ indicate that server's measured performance is lower than 300 leases
+ per second. Further rate decrease should eliminate most of the packet
+ drops and bring achived rate close to expected rate:
+ </p><pre class="screen"><strong class="userinput"><code>#./perfdhcp -l eth3 -p 60 -r 100 -R 30</code></strong>
+***Rate statistics***
+Rate: 99.8164 exchanges/second, expected rate: 100 exchanges/second
+
+***Statistics for: DISCOVER-OFFER***
+sent packets: 5989
+received packets: 5989
+drops: 0
+orphans: 0
+
+min delay: 0.023 ms
+avg delay: 2.198 ms
+max delay: 181.760 ms
+std deviation: 9.429 ms
+collected packets: 0
+
+***Statistics for: REQUEST-ACK***
+sent packets: 5989
+received packets: 5989
+drops: 0
+orphans: 0
+
+min delay: 0.473 ms
+avg delay: 2.355 ms
+max delay: 189.658 ms
+std deviation: 5.876 ms
+collected packets: 0
+ </pre><p>
+ Note that the last parameter (-R 30) configures perfdhcp to simulate
+ traffic from distinct 30 clients.
+ </p></div><div class="section" title="Example: templates"><div class="titlepage"><div><div><h3 class="title"><a name="perfdhcp-templates"></a>Example: templates</h3></div></div></div><p>
+ By default the DHCP messages are formed in-flight with default options.
+ If desired, there is a way to define custom packet format with template
+ files. Content in template files is encoded in hexadecimal format. The
+ perfdhcp forms the packet by replacing parts of the binary stream read
+ from the file with variable data such as elapsed time, HW address, DUID
+ etc. The offsets where such variable data is placed is specific to the
+ template file and have to be specified from the command line. Refer to
+ <a class="xref" href="#perfdhcp-command-line" title="Command line options">the section called “Command line options”</a> to find out how to
+ specify offsets for particular options and fields. With the following
+ command line the DHCPv6 SOLICIT and REQUEST packets will be formed from
+ solicit-example.hex and request6-example.hex packets:
+ </p><pre class="screen"><strong class="userinput"><code>#./perfdhcp -6 -l eth3 -r 100 -R 20 -T templates/solicit-example.hex -T templates/request6-example.hex -O 21 -E 84 -S 22 -I 40 servers</code></strong>
+***Rate statistics***
+Rate: 99.5398 exchanges/second, expected rate: 100 exchanges/second
+
+***Statistics for: SOLICIT-ADVERTISE***
+sent packets: 570
+received packets: 569
+drops: 1
+orphans: 0
+
+min delay: 0.259 ms
+avg delay: 0.912 ms
+max delay: 6.979 ms
+std deviation: 0.709 ms
+collected packets: 0
+
+***Statistics for: REQUEST-REPLY***
+sent packets: 569
+received packets: 569
+drops: 0
+orphans: 0
+
+min delay: 0.084 ms
+avg delay: 0.607 ms
+max delay: 6.490 ms
+std deviation: 0.518 ms
+collected packets: 0
+ </pre><p>
+ where:
+ </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>two occurences of -O 21 - DUID's last octet
+ positions in SOLICIT and REQUEST respectively.</p></li><li class="listitem"><p>-E 84 - elapsed time option position in
+ REQUEST template</p></li><li class="listitem"><p>-S 22 - server id position in REQUEST
+ template</p></li><li class="listitem"><p>-I 40 - IA_NA option position in REQUEST
+ template</p></li></ul></div><p>
+ </p></div></div></div></div></body></html>
\ No newline at end of file
well.
</para>
</section>
-
- <section>
+ <section id="perfdhcp-key-features">
<title>Key features</title>
<para>
The perfdhcp exposes the number of command line parameters to
<para>
Rate control - control how many DHCP exchanges
are initiated within a period of time. Tool can also simulate
- best effort conditions where it attempts to start as many
- exchanges as possible.
+ best effort conditions attempting to initiate as many DHCP
+ packet exchanges within a unit of time as possible.
</para>
</listitem>
<listitem>
</orderedlist>
</para>
</section>
-
<section id="perfdhcp-command-line">
<title>Command line options</title>
<para>
</screen>
</para>
</section>
- <section>
- <title>Running a test</title>
+ <section id="starting-perfdhcp">
+ <title>Starting perfdhcp</title>
<para>
In order to run performance test at least two separate systems
have to be installed: client and server. The first one has to have
</para>
<para>
The DHCP operates on low port numbers (67 for DHCPv4 relays and
- 547 for DHCPv6) running perfdhcp with non-root priviliges will
+ 547 for DHCPv6). Running perfdhcp with non-root priviliges will
usually result in the error message similar to this:
<screen><userinput>$./perfdhcp -4 -l eth3 -r 100 all</userinput>
Error running perfdhcp: Failed to bind socket 3 to 172.16.1.2/port=67
</screen>
- perfdhcp exposes '-L' command line option that
- imposes use of custom local port and the following command line will
- work:
+ perfdhcp has the '-L' command line option that
+ imposes use of custom local port. Thus the following command
+ line will work:
<screen><userinput>$./perfdhcp -4 -l eth3 -r 100 -L 10067 all</userinput></screen>
but in the standard configuration no responses will be received
from the ISC DHCP server because server responds to default relay
port 67.
+ Alternative way to overcome this issue is to run perfdhcp as root.
</para>
<para>
- Alternative way to overcome the issue with lack of privileges
- to use default DHCP port number is to run perfdhcp as root.
+ Currently, perfdhcp is seen from the server perspective as relay agent.
+ This simplifies its implementation (specifically there is no need to
+ receive traffic sent to braodcast addresses). This imposes that IPv4
+ address has to be set manually on the interface that will be used to
+ communicate with the server. For example, if DHCPv4 server is listening
+ on the interface connected to 172.16.1.0 subnet, interface on client
+ machine has to have network address assigned from the same subnet
+ on one of its interfaces connected to this subnet:
+ <screen><userinput>#ifconfig eth3 172.16.1.2. netmask 255.255.255.0 up</userinput></screen>
</para>
-
+ </section>
+ <section id="perfdhcp-commandline-examples">
+ <title>perfdhcp command line examples</title>
<para>
- In this section the perfdhcp command line options examples
+ In this section the perfdhcp command line examples
are presented as a quick start guide for new users. For the
detailed list of command line options refer to
<xref linkend="perfdhcp-command-line"/>.
</para>
- <para>
- <screen>
- <userinput></userinput>
- </screen>
- </para>
+ <section id="perfdhcp-basic-usage">
+ <title>Example: basic usage</title>
+ <para>
+ If server is listening on interface with IPv4 address 172.16.1.1
+ the simpliest perfdhcp command line will look like this:
+ <screen><userinput>#./perfdhcp 172.16.1.1</userinput>
+***Rate statistics***
+Rate: 206.345
+
+***Statistics for: DISCOVER-OFFER***
+sent packets: 21641
+received packets: 350
+drops: 21291
+orphans: 0
+
+min delay: 9.022 ms
+avg delay: 143.100 ms
+max delay: 259.303 ms
+std deviation: 56.074 ms
+collected packets: 30
+
+***Statistics for: REQUEST-ACK***
+sent packets: 350
+received packets: 268
+drops: 82
+orphans: 0
+
+min delay: 3.010 ms
+avg delay: 152.470 ms
+max delay: 258.634 ms
+std deviation: 56.936 ms
+collected packets: 0
+ </screen>
+ In this case perfdhcp will use remote address 172.16.1.1 as a
+ destination address and will use suitable local interface for
+ communication. Since, no rate control parameters have been specified
+ it will be initiating DHCP exchanges with the maximum possible
+ rate (it will try to initiate maximum number of exchanges per
+ second and count number of completed exchanged). Due to server's
+ performance constraints, many DHCP packets sent to server are likely
+ to be dropped. The performance test will be running until it is
+ not interrupted by the user (with ^C).
+ </para>
+ <para>
+ The default performance statistics reported by perfdhcp have the
+ following meaning:
+ <itemizedlist>
+ <listitem><para>Rate - number of packet exchanges (packet sent
+ to the server and matching response received from the server)
+ completed within a second.</para></listitem>
+ <listitem><para>sent packets - total number of DHCP packets of
+ a specific type sent to the server.</para></listitem>
+ <listitem><para>received packets - total number of DHCP packets
+ of specific type received from the server.</para></listitem>
+ <listitem><para>drops - number of dropped packets for the
+ particular exchange. Number of dropped packets is calculated as
+ a difference between number of sent packets and number of
+ response packets received from the server. It is likely that
+ server sent the reponse but perfdhcp execution had ended before
+ reponse arrived. In such case this packet will be assumed
+ dropped.</para></listitem>
+ <listitem><para>orphans - number of packets that have been
+ received from the server and did not match any packet sent by
+ perfdhcp. This may occur if received packet has been sent
+ to some other host or if exchange time out has occured and
+ has been been garbage collected.</para></listitem>
+ <listitem><para>min delay - minimum delay that occured between
+ sending the packet to the server and receiving reponse from
+ it.</para></listitem>
+ <listitem><para>avg delay - average delay between sending the
+ packet of the specific type the server and receiving response
+ from it.</para></listitem>
+ <listitem><para>max delay - maximum delat that occured between
+ sedning the packet to the server and receiveing response from
+ it.</para></listitem>
+ <listitem><para>std deviation - standard deviation of delay
+ between sending the packet of a specific type to the server and
+ receiving response from it.</para></listitem>
+ <listitem><para>collected packets - number of garbage collected
+ sent packets. Packets may get garbage collected when waiting time
+ for server response exceeds value set with
+ <![CDATA[-d<drop-time>]]>.</para></listitem>
+ </itemizedlist>
+ </para>
+ <para>
+ perfdhcp allows to run the test using specified interface:
+ <screen><userinput>#./perfdhcp -l eth3</userinput></screen>
+ or local address assigned to it:
+ <screen><userinput>#./perfdhcp -l 172.16.1.2</userinput></screen>
+ </para>
+ </section>
+ <section id="perfdhcp-rate-control">
+ <title>Example: rate control</title>
+ <para>
+ In the examples above perfdhcp initiates new exchanges with best
+ effort rate. In this case many packets is expected to be dropped by the
+ server due to performance limitations. Many times it is desired to set
+ the expected (reasonable) rate and verify if generated traffic is
+ handled without packet dropes by DHCP server. The following command will
+ make perfdhcp to initiate 300 4-way exchanges per second and test will
+ last for 60 seconds:
+ <screen><userinput>#./perfdhcp -l eth3 -p 60 -r 300</userinput>
+***Rate statistics***
+Rate: 256.683 exchanges/second, expected rate: 300 exchanges/second
+
+***Statistics for: DISCOVER-OFFER***
+sent packets: 17783
+received packets: 15401
+drops: 2382
+orphans: 0
+
+min delay: 0.109 ms
+avg delay: 75.756 ms
+max delay: 575.614 ms
+std deviation: 60.513 ms
+collected packets: 11
+
+***Statistics for: REQUEST-ACK***
+sent packets: 15401
+received packets: 15317
+drops: 84
+orphans: 0
+
+min delay: 0.536 ms
+avg delay: 72.072 ms
+max delay: 576.749 ms
+std deviation: 58.189 ms
+collected packets: 0
+ </screen>
+ Note that in this example the packet drops have been significantly
+ reduced thanks to setting reasonable rate. The non-zero number of
+ packet drops and achived rate (256/s) below expected rate (300/s)
+ indicate that server's measured performance is lower than 300 leases
+ per second. Further rate decrease should eliminate most of the packet
+ drops and bring achived rate close to expected rate:
+ <screen><userinput>#./perfdhcp -l eth3 -p 60 -r 100 -R 30</userinput>
+***Rate statistics***
+Rate: 99.8164 exchanges/second, expected rate: 100 exchanges/second
+
+***Statistics for: DISCOVER-OFFER***
+sent packets: 5989
+received packets: 5989
+drops: 0
+orphans: 0
+
+min delay: 0.023 ms
+avg delay: 2.198 ms
+max delay: 181.760 ms
+std deviation: 9.429 ms
+collected packets: 0
+
+***Statistics for: REQUEST-ACK***
+sent packets: 5989
+received packets: 5989
+drops: 0
+orphans: 0
+
+min delay: 0.473 ms
+avg delay: 2.355 ms
+max delay: 189.658 ms
+std deviation: 5.876 ms
+collected packets: 0
+ </screen>
+ Note that the last parameter (-R 30) configures perfdhcp to simulate
+ traffic from distinct 30 clients.
+ </para>
+ </section>
+ <section id="perfdhcp-templates">
+ <title>Example: templates</title>
+ <para>
+ By default the DHCP messages are formed in-flight with default options.
+ If desired, there is a way to define custom packet format with template
+ files. Content in template files is encoded in hexadecimal format. The
+ perfdhcp forms the packet by replacing parts of the binary stream read
+ from the file with variable data such as elapsed time, HW address, DUID
+ etc. The offsets where such variable data is placed is specific to the
+ template file and have to be specified from the command line. Refer to
+ <xref linkend="perfdhcp-command-line"/> to find out how to
+ specify offsets for particular options and fields. With the following
+ command line the DHCPv6 SOLICIT and REQUEST packets will be formed from
+ solicit-example.hex and request6-example.hex packets:
+ <screen><userinput>#./perfdhcp -6 -l eth3 -r 100 -R 20 -T templates/solicit-example.hex -T templates/request6-example.hex -O 21 -E 84 -S 22 -I 40 servers</userinput>
+***Rate statistics***
+Rate: 99.5398 exchanges/second, expected rate: 100 exchanges/second
+
+***Statistics for: SOLICIT-ADVERTISE***
+sent packets: 570
+received packets: 569
+drops: 1
+orphans: 0
+
+min delay: 0.259 ms
+avg delay: 0.912 ms
+max delay: 6.979 ms
+std deviation: 0.709 ms
+collected packets: 0
+
+***Statistics for: REQUEST-REPLY***
+sent packets: 569
+received packets: 569
+drops: 0
+orphans: 0
+
+min delay: 0.084 ms
+avg delay: 0.607 ms
+max delay: 6.490 ms
+std deviation: 0.518 ms
+collected packets: 0
+ </screen>
+ where:
+ <itemizedlist>
+ <listitem><para>two occurences of -O 21 - DUID's last octet
+ positions in SOLICIT and REQUEST respectively.</para></listitem>
+ <listitem><para>-E 84 - elapsed time option position in
+ REQUEST template</para></listitem>
+ <listitem><para>-S 22 - server id position in REQUEST
+ template</para></listitem>
+ <listitem><para>-I 40 - IA_NA option position in REQUEST
+ template</para></listitem>
+ </itemizedlist>
+ </para>
+ </section>
</section>
</chapter>
</book>
projects / thirdparty / kea.git / commitdiff
