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@@ -22,9 +22,9 @@
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- PERFORMANCE OF THIS SOFTWARE.
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-->
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-<book>
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- <?xml-stylesheet href="bind10-guide.css" type="text/css"?>
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+<?xml-stylesheet href="bind10-guide.css" type="text/css"?>
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+<book>
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<bookinfo>
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<title>DHCP Performance Guide</title>
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<!-- <subtitle>Various aspects of DHCP Performance in BIND 10</subtitle> -->
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@@ -37,7 +37,10 @@
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<firstname>Tomasz</firstname>
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<surname>Mrugalski</surname>
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</author>
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-
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+ <author>
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+ <firstname>Marcin</firstname>
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+ <surname>Siodelski</surname>
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+ </author>
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<abstract>
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<para>BIND 10 is a framework that features Domain Name System
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(DNS) suite and Dynamic Host Configuration Protocol (DHCP)
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@@ -586,9 +589,252 @@ SQLite version: 3.7.9sourceid version is 2011-11-01 00:52:41 c7c6050ef060877ebe7
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<chapter id="perfdhcp">
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<title>perfdhcp</title>
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- <para>
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- TODO: Write something about perfdhcp here.
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- </para>
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- </chapter>
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+ <section>
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+ <title>Purpose</title>
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+ <para>
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+ There is a growing need to evaluate performance of DHCP servers in
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+ different traffic conditions to understand their bottle necks.
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+ This helps to elimante bugs in existing DHCP software as well
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+ as make informed decisions regarding new DHCP software designs
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+ to significantly improve its performance. The perfdhcp tool has
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+ been created to fill the gap in performance measurement capabilities
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+ mostly. However, the number of implemented features and parameters
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+ exposed to the user make this tool useful for functional testing as
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+ well.
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+ </para>
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+ </section>
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+
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+ <section>
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+ <title>Key features</title>
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+ <para>
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+ The perfdhcp exposes the number of command line parameters to
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+ control DHCP message exchanges. Currently they fall back to
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+ the following categories:
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+ <orderedlist>
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+ <listitem>
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+ <para>
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+ Rate control - control how many DHCP exchanges
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+ are initiated within a period of time. Tool can also simulate
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+ best effort conditions where it attempts to start as many
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+ exchanges as possible.
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+ </para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ Test exit specifiers - control the conditions when test
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+ completes including number of initiated exchanges, test period or
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+ maximum number of dropped packets.
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+ </para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ Packet templates - specify files containing packet templates that
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+ are used by perfdhcp to create custom DHCP messages instead of
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+ default. Tool also allows to specify number of values indicating
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+ offsets of variable values within a packet that are modified in
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+ flight by the tool.
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+ </para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ Reporting - for each test produce the set of performance data
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+ including achieved packet exchange rate (server performance).
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+ There is also a number of diagnostic selectors available that
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+ enable periodic (intermediate) reporting, packet timestamps
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+ printing and detailed information about perfdhcp internal
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+ states (for debugging).
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+ </para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ Different mode of operations - specify DHCP version used
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+ (v4 or v6), 2-way or 4-way exchanges, use Rapid Commit option
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+ for DHCPv6.
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+ </para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ IP layer options - specify local/remote address, local interface
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+ and local port to be used for communication with DHCP server.
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+ </para>
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+ </listitem>
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+ </orderedlist>
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+ </para>
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+ </section>
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+
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+ <section id="perfdhcp-command-line">
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+ <title>Command line options</title>
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+ <para>
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+ The following command line options may be used with perfdhcp tool.
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+ This summary also presents its possible exit codes as well as
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+ error counters printed along when test is complete:
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+ <screen>$ <userinput>./perfdhcp -h</userinput>
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+<![CDATA[perfdhcp [-hv] [-4|-6] [-r<rate>] [-t<report>] [-R<range>] [-b<base>]
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+ [-n<num-request>] [-p<test-period>] [-d<drop-time>] [-D<max-drop>]
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+ [-l<local-addr|interface>] [-P<preload>] [-a<aggressivity>]
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+ [-L<local-port>] [-s<seed>] [-i] [-B] [-c] [-1]
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+ [-T<template-file>] [-X<xid-offset>] [-O<random-offset]
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+ [-E<time-offset>] [-S<srvid-offset>] [-I<ip-offset>]
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+ [-x<diagnostic-selector>] [-w<wrapped>] [server]
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+
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+The [server] argument is the name/address of the DHCP server to
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+contact. For DHCPv4 operation, exchanges are initiated by
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+transmitting a DHCP DISCOVER to this address.
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+
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+For DHCPv6 operation, exchanges are initiated by transmitting a DHCP
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+SOLICIT to this address. In the DHCPv6 case, the special name 'all'
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+can be used to refer to All_DHCP_Relay_Agents_and_Servers (the
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+multicast address FF02::1:2), or the special name 'servers' to refer
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+to All_DHCP_Servers (the multicast address FF05::1:3). The [server]
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+argument is optional only in the case that -l is used to specify an
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+interface, in which case [server] defaults to 'all'.
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+
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+The default is to perform a single 4-way exchange, effectively pinging
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+the server.
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+The -r option is used to set up a performance test, without
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+it exchanges are initiated as fast as possible.
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+
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+Options:
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+-1: Take the server-ID option from the first received message.
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+-4: DHCPv4 operation (default). This is incompatible with the -6 option.
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+-6: DHCPv6 operation. This is incompatible with the -4 option.
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+-a<aggressivity>: When the target sending rate is not yet reached,
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+ control how many exchanges are initiated before the next pause.
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+-b<base>: The base mac, duid, IP, etc, used to simulate different
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+ clients. This can be specified multiple times, each instance is
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+ in the <type>=<value> form, for instance:
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+ (and default) mac=00:0c:01:02:03:04.
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+-d<drop-time>: Specify the time after which a request is treated as
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+ having been lost. The value is given in seconds and may contain a
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+ fractional component. The default is 1 second.
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+-E<time-offset>: Offset of the (DHCPv4) secs field / (DHCPv6)
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+ elapsed-time option in the (second/request) template.
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+ The value 0 disables it.
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+-h: Print this help.
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+-i: Do only the initial part of an exchange: DO or SA, depending on
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+ whether -6 is given.
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+-I<ip-offset>: Offset of the (DHCPv4) IP address in the requested-IP
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+ option / (DHCPv6) IA_NA option in the (second/request) template.
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+-l<local-addr|interface>: For DHCPv4 operation, specify the local
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+ hostname/address to use when communicating with the server. By
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+ default, the interface address through which traffic would
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+ normally be routed to the server is used.
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+ For DHCPv6 operation, specify the name of the network interface
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+ via which exchanges are initiated.
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+-L<local-port>: Specify the local port to use
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+ (the value 0 means to use the default).
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+-O<random-offset>: Offset of the last octet to randomize in the template.
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+-P<preload>: Initiate first <preload> exchanges back to back at startup.
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+-r<rate>: Initiate <rate> DORA/SARR (or if -i is given, DO/SA)
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+ exchanges per second. A periodic report is generated showing the
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+ number of exchanges which were not completed, as well as the
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+ average response latency. The program continues until
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+ interrupted, at which point a final report is generated.
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+-R<range>: Specify how many different clients are used. With 1
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+ (the default), all requests seem to come from the same client.
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+-s<seed>: Specify the seed for randomization, making it repeatable.
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+-S<srvid-offset>: Offset of the server-ID option in the
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+ (second/request) template.
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+-T<template-file>: The name of a file containing the template to use
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+ as a stream of hexadecimal digits.
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+-v: Report the version number of this program.
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+-w<wrapped>: Command to call with start/stop at the beginning/end of
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+ the program.
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+-x<diagnostic-selector>: Include extended diagnostics in the output.
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+ <diagnostic-selector> is a string of single-keywords specifying
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+ the operations for which verbose output is desired. The selector
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+ keyletters are:
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+ * 'a': print the decoded command line arguments
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+ * 'e': print the exit reason
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+ * 'i': print rate processing details
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+ * 'r': print randomization details
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+ * 's': print first server-id
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+ * 't': when finished, print timers of all successful exchanges
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+ * 'T': when finished, print templates
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+-X<xid-offset>: Transaction ID (aka. xid) offset in the template.
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+
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+DHCPv4 only options:
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+-B: Force broadcast handling.
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+
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+DHCPv6 only options:
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+-c: Add a rapid commit option (exchanges will be SA).
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+
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+The remaining options are used only in conjunction with -r:
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+
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+-D<max-drop>: Abort the test if more than <max-drop> requests have
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+ been dropped. Use -D0 to abort if even a single request has been
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+ dropped. If <max-drop> includes the suffix '%', it specifies a
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+ maximum percentage of requests that may be dropped before abort.
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+ In this case, testing of the threshold begins after 10 requests
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+ have been expected to be received.
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+-n<num-request>: Initiate <num-request> transactions. No report is
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+ generated until all transactions have been initiated/waited-for,
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+ after which a report is generated and the program terminates.
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+-p<test-period>: Send requests for the given test period, which is
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+ specified in the same manner as -d. This can be used as an
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+ alternative to -n, or both options can be given, in which case the
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+ testing is completed when either limit is reached.
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+-t<report>: Delay in seconds between two periodic reports.
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+
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+Errors:
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+- tooshort: received a too short message
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+- orphans: received a message which doesn't match an exchange
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+ (duplicate, late or not related)
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+- locallimit: reached to local system limits when sending a message.
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+
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+Exit status:
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+The exit status is:
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+0 on complete success.
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+1 for a general error.
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+2 if an error is found in the command line arguments.
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+3 if there are no general failures in operation, but one or more
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+ exchanges are not successfully completed.
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+]]>
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+ </screen>
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+ </para>
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+ </section>
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+ <section>
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+ <title>Running a test</title>
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+ <para>
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+ In order to run performance test at least two separate systems
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+ have to be installed: client and server. The first one has to have
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+ perfdhcp tool installed, the latter has to have DHCP server
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+ running (v4 or v6). If only single system is available the client
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+ and server can be run on virtual machines (running on the same
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+ phisical system) but in this case performance data may be heavily
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+ impacted by the performance of VMs.
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+ </para>
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+ <para>
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+ The DHCP operates on low port numbers (67 for DHCPv4 relays and
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+ 547 for DHCPv6) running perfdhcp with non-root priviliges will
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+ usually result in the error message similar to this:
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+ <screen><userinput>$./perfdhcp -4 -l eth3 -r 100 all</userinput>
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+Error running perfdhcp: Failed to bind socket 3 to 172.16.1.2/port=67
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+ </screen>
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+ perfdhcp exposes '-L' command line option that
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+ imposes use of custom local port and the following command line will
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+ work:
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+ <screen><userinput>$./perfdhcp -4 -l eth3 -r 100 -L 10067 all</userinput></screen>
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+ but in the standard configuration no responses will be received
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+ from the ISC DHCP server because server responds to default relay
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+ port 67.
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+ </para>
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+ <para>
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+ Alternative way to overcome the issue with lack of privileges
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+ to use default DHCP port number is to run perfdhcp as root.
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+ </para>
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+ <para>
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+ In this section the perfdhcp command line options examples
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+ are presented as a quick start guide for new users. For the
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+ detailed list of command line options refer to
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+ <xref linkend="perfdhcp-command-line"/>.
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+ </para>
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+ <para>
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+ <screen>
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+ <userinput></userinput>
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+ </screen>
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+ </para>
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+ </section>
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+ </chapter>
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</book>
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Marcin Siodelski