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Smokeping_probes_IRTT(3)	   SmokePing	      Smokeping_probes_IRTT(3)

NAME
       Smokeping::probes::IRTT - a SmokePing Probe for IRTT
       <https://github.com/peteheist/irtt>

SYNOPSIS
	*** Probes ***

	+IRTT

	binary = /usr/local/bin/irtt # mandatory
	forks =	5
	offset = 50%
	step = 300
	timeout	= 15
	tmpdir = /tmp/smokeping-irtt

	# The following	variables can be overridden in each target section
	/^influx_.+/ = influx_location = In the	basement
	dscp = 46
	extraargs = --ttl=32
	fill = rand
	hmac = opensesame
	interval = 1.5
	ipversion = 6
	length = 172
	localaddr = 192.168.1.10:63814
	metric = rtt
	pings =	5
	readfrom = irtt1
	readfrompollinterval = 2
	serverfill = rand
	sleep =	0.5
	writeto	= irtt1

	# [...]

	*** Targets ***

	probe =	IRTT # if this should be the default probe

	# [...]

	+ mytarget
	# probe	= IRTT # if the	default	probe is something else
	host = my.host
	/^influx_.+/ = influx_location = In the	basement
	dscp = 46
	extraargs = --ttl=32
	fill = rand
	hmac = opensesame
	interval = 1.5
	ipversion = 6
	length = 172
	localaddr = 192.168.1.10:63814
	metric = rtt
	pings =	5
	readfrom = irtt1
	readfrompollinterval = 2
	serverfill = rand
	sleep =	0.5
	writeto	= irtt1

DESCRIPTION
       This SmokePing probe uses IRTT <https://github.com/peteheist/irtt> to
       record network round-trip time <https://en.wikipedia.org/wiki/Round-
       trip_delay_time>, one-way delay <https://en.wikipedia.org/wiki/End-to-
       end_delay> or IPDV
       <https://en.wikipedia.org/wiki/Packet_delay_variation> (jitter),	based
       on the value of the metric variable.

       Additionally, the probe provides	a results sharing feature, which
       allows using results from a single IRTT run to record multiple metrics
       for a given host	at the same time. One target is	defined	with the
       writeto variable	set, which selects the name of a temporary file	to
       save the	IRTT output to.	Additional targets are defined with the
       readfrom	variable set to	the same value,	which, instead of running
       IRTT, wait for the main target's	output to become available, then parse
       it to record the	chosen metric from the same data. See the writeto and
       readfrom	variables for more information.

   WARNING
       The results sharing feature (writeto and	readfrom variables) requires
       the number of forks for the IRTT	probe to be at least the total number
       of IRTT targets defined (regardless of whether they have	writeto	and
       readfrom	set). Otherwise, there can be a	deadlock while readfrom
       targets wait for	their corresponding writeto target to complete,	which
       may never start.

VARIABLES
       Supported probe-specific	variables:

       binary
	   The location	of your	irtt binary.

	   Example value: /usr/local/bin/irtt

	   Default value: /usr/bin/irtt

	   This	setting	is mandatory.

       forks
	   Run this many concurrent processes at maximum

	   Example value: 5

	   Default value: 5

       offset
	   If  you  run	 many probes concurrently you may want to prevent them
	   from	hitting	your network all at the	same time.  Using  the	probe-
	   specific  offset  parameter	you  can change	the point in time when
	   each	probe will be run. Offset is specified in % of total interval,
	   or alternatively as 'random', and the  offset  from	the  'General'
	   section  is	used if	nothing	is specified here. Note	that this does
	   NOT influence the rrds itself, it is	just a	matter	of  when  data
	   acquisition is initiated.  (This variable is	only applicable	if the
	   variable 'concurrentprobes' is set in the 'General' section.)

	   Example value: 50%

       step
	   Duration  of	 the  base  interval  that  this  probe	should use, if
	   different from the one specified in the  'Database'	section.  Note
	   that	 the  step  in the RRD files is	fixed when they	are originally
	   generated, and if you change	the step parameter afterwards,	you'll
	   have	 to  delete  the  old RRD files	or somehow convert them. (This
	   variable is only applicable if the variable	'concurrentprobes'  is
	   set in the 'General'	section.)

	   Example value: 300

       timeout
	   How long a single 'ping' takes at maximum

	   Example value: 15

	   Default value: 5

       tmpdir
	   A temporary directory in which to place files for writeto/readfrom.

	   Default value: /tmp/smokeping-irtt

       Supported target-specific variables:

       /^influx_.+/
	   This	 is  a	tag that will be sent to influxdb and has no impact on
	   the probe measurement. The  tag  name  will	be  sent  without  the
	   "influx_"  prefix, which will be replaced with "tag_" instead. Tags
	   can be used for filtering.

	   Example value: influx_location = In the basement

       dscp
	   The				 packet				  DSCP
	   <https://en.wikipedia.org/wiki/Differentiated_services>   value  to
	   use ("irtt client --dscp"). This is the same	 as  the  classic  one
	   byte	 IP  ToS field,	but on the modern Internet, typically only the
	   lower 6 bits	are used, and this is called the DSCP value. The upper
	   two	      bits	  are	      reserved	       for	   ECN
	   <https://en.wikipedia.org/wiki/Explicit_Congestion_Notification>.
	   Hex may be used if prefixed by "0x".

	   Example value: 46

       extraargs
	   Extra  arguments  to	"irtt client" (see irtt-client(1)). Be careful
	   with	extra arguments, as some can corrupt the results.

	   Example value: --ttl=32

       fill
	   The fill to use in the payload for  the  client  to	server	packet
	   ("irtt client --fill"). The length variable must be large enough so
	   there's  a  payload	to  fill.   Use	 rand  for random fill,	or see
	   irtt-client(1) for more options.

	   Example value: rand

       hmac
	   The		  HMAC		  <https://en.wikipedia.org/wiki/Hash-
	   based_message_authentication_code>  key to use when sending packets
	   to the server ("irtt	client --hmac").

	   Example value: opensesame

       interval
	   The interval	between	successive requests, in	seconds	("irtt	client
	   -i",	but the	unit is	always seconds (s)).

	   WARNING

	   If  interval	 is  increased	to greater than	5 seconds, the timeout
	   (which defaults to pings * 5	seconds	+ 1) must be modified so  that
	   SmokePing   doesn't	 kill  the  probe  prematurely.	 Additionally,
	   interval must not be	 increased  such  that	pings  *  interval  is
	   greater  than  step.	 For  example,	at  step=300 and pings=20, the
	   interval must not be	greater	than 15	seconds, but should preferably
	   be less to account for handshake and	packet wait times.

	   Example value: 1.5

	   Default value: 1

       ipversion
	   The IP version to use for packets (4	or 6, corresponding  to	 "irtt
	   client  -4"	or  "irtt  client  -6").  By default the IP version is
	   chosen based	on the supplied	host variable.

	   Example value: 6

       length
	   The length (size) of	the packet  ("irtt  client  -l").  The	length
	   includes IRTT headers, but not IP or	UDP headers. The actual	packet
	   length  is increased	to accommodate the IRTT	headers, if necessary.
	   Header size as of IRTT 0.9.0	as used	in SmokePing is	48 bytes  when
	   writeto  is	set  (since  both  monotonic and wall clock values are
	   requested) and 40 bytes otherwise.

	   Example value: 172

       localaddr
	   The local address to	bind to	when  sending  packets	("irtt	client
	   --local").  See irtt-client(1) Host formats for valid syntax.

	   Example value: 192.168.1.10:63814

       metric
	   The metric to record, one of:

	      rtt:   round-trip   time	 <https://en.wikipedia.org/wiki/Round-
	       trip_delay_time>

	      send: one-way send delay	<https://en.wikipedia.org/wiki/End-to-
	       end_delay> (requires external time synchronization)

	      receive:		   one-way	      receive		 delay
	       <https://en.wikipedia.org/wiki/End-to-end_delay>	     (requires
	       external	time synchronization)

	      ipdv:							  IPDV
	       <https://en.wikipedia.org/wiki/Packet_delay_variation>
	       (instantaneous packet delay variation, or jitter)

	      send_ipdv: IPDV for sent	packets

	      receive_ipdv: IPDV for received packets

	   Note	 that  the  "send"  and	 "receive"  metrics  require  accurate
	   external system clock synchronization, otherwise  the  values  from
	   one will be abnormally high and the other will be abnormally	low or
	   even	 negative,  in which case the value 0 will be given SmokePing.
	   It is recommended to	install	ntp on both the	SmokePing  client  and
	   IRTT	 server.  Properly  configured	NTP may	be able	to synchronize
	   time	to within a few	 milliseconds,	which  is  usually  enough  to
	   provide  useful  results.   PTP over	a LAN may achieve microsecond-
	   level accuracy. For	best  results  between	geographically	remote
	   hosts,   GPS	  receivers   may   be	used.  Since  "send_ipdv"  and
	   "receive_ipdv" measure the variation	in  times  between  successive
	   packets,  and  since	"rtt" and "ipdv" use monotonic clock values on
	   the client side only, external time synchronization is not required
	   for these metrics.

	   Default value: rtt

       pings
	   How many pings should be sent to each target, if different from the
	   global value	specified in  the  Database  section.  Note  that  the
	   number  of pings in the RRD files is	fixed when they	are originally
	   generated, and if you change	this parameter afterwards, you'll have
	   to delete the old RRD files or somehow convert them.

	   Example value: 5

       readfrom
	   The name of a file to read results from, instead of	running	 IRTT.
	   Use	in  combination	 with writeto to use the results from one IRTT
	   run to record multiple metrics. The value will become the name of a
	   file	in tmpdir, and must be the same	as  another  target's  setting
	   for	writeto. Multiple targets may use the same value for readfrom,
	   but writeto and readfrom may	not be both set	for  a	given  target.
	   When	 readfrom  is set, any variables that affect "irtt client" are
	   ignored  because  IRTT  is  not  being  invoked,  including:	 dscp,
	   extraargs,  fill,  hmac, interval, ipversion, length, localaddr and
	   serverfill. These values are	only  relevant	in  the	 corresponding
	   writeto target.

	   Note	 that the host variable	must still be defined for targets that
	   define readfrom, otherwise the target won't be used.

	   When	using this feature, be sure to have at least as	many forks for
	   the IRTT probe as you have total  IRTT  targets  defined.  See  the
	   "DESCRIPTION" section for more information.

	   Example value: irtt1

       readfrompollinterval
	   The	integer	 interval in seconds on	which to poll for results when
	   readfrom is set. Lower numbers  will	 allow	readfrom  to  see  the
	   results a bit sooner, at the	cost of	higher CPU usage. Polling does
	   not	begin  until  the  soonest time	at which the IRTT client could
	   have	terminated normally.

	   Example value: 2

	   Default value: 5

       serverfill
	   The fill to use in the payload for  the  server  to	client	packet
	   ("irtt  client  --sfill"). The length variable must be large	enough
	   to accommodate a payload.  Use  "rand"  for	random	fill,  or  see
	   irtt-client(1) for more options.

	   Example value: rand

       sleep
	   The	amount of time to sleep	before starting	requests or processing
	   results (a float in seconds). This may be used to avoid CPU	spikes
	   caused by invoking multiple instances of IRTT at the	same time.

	   Example value: 0.5

       writeto
	   The	name  of a file	to write results to after running IRTT.	Use in
	   combination with readfrom to	use the	results	from this IRTT run  to
	   record  multiple  metrics. The value	will become the	name of	a file
	   in tmpdir, and any targets with readfrom set	to the same value will
	   use this target's results. There  must  be  only  one  target  with
	   writeto  set	 for a given file, and writeto and readfrom may	not be
	   both	set for	a given	target.

	   When	using this feature, be sure to have at least as	many forks for
	   the IRTT probe as you have total  IRTT  targets  defined.  See  the
	   "DESCRIPTION" section for more information.

	   Example value: irtt1

AUTHORS
       Pete Heist <pete@heistp.net>

2.9.0				  2025-04-18	      Smokeping_probes_IRTT(3)

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