Test and Tool Reference


Everything in pScheduler begins with requesting a test which in turn will be carried-out by a tool. When you run the pscheduler task command the first required argument is the test type and all arguments that follow are dependent on the type of test. The document aims to give you a list of tests and their corresponding tools provided by a default pScheduler installation on perfSONAR. It also tries to give an idea of the options available in each and other important details.


This document highlights the list of test types and tools installed by default when installing pScheduler with perfSONAR. It is possible for others to write their own test and tool plug-ins so this list may not be exhaustive of all tests and tools available.

Test Types


Description:Measure the clock difference between hosts


Description:Measure DNS transaction time


Description:Measure one-way latency and associated statistics between hosts


Description:Continuously measure one-way latency and associated statistics between hosts and report back results periodically


Description:Measure the round trip time and related statistics between hosts


Description:Used primarily for testing, sends a simple “HELLO” message between two hosts using TCP


Description:A test to measure the observed speed of a data transfer and associated statistics between two endpoints
Tools:iperf3, iperf2, nuttcp, bwctliperf3, bwctliperf2


Description:Trace the path between IP hosts
Tools:traceroute, tracepath, paris-traceroute

Test Classifications

Each test classified in one of three categories thatd etermines what other tests can be run in parallel:

  1. Exclusive - These are tests that cannot run at the same time as any other exclusive or normal test. An example is a throughput test. If you have very little whitespace in this category then you may have difficulty finding a timeslot for new tests.
  2. Normal - These are tests that can run at the same time as other normal and background tests, but cannot run at the same time as exclusive tests. Currently there are no examples of these in the default test set, but the classification is available for those writing new tools.
  3. Background - These are tests that can be run in parallel with any other test including exclusive, normal and other background tests. Example test types include latency, latencybg, rtt and trace. It is not uncommon to have this column look almost entirely solid if you have latencybg tests since they run continuously. Since these runs do not prevent other runs from executing though, they should not limit your ability to schedule new tests.

throughput Tests

Throughput tests support the following arguments:

pscheduler task throughput --help
Usage: task [task-options] throughput [test-options]
 -h, --help            show this help message and exit
 -s SOURCE, --source=SOURCE
                       Sending host
                       pScheduler node on sending host, if different
                       Receiving host
                       pScheduler node on receiving host, if different
 -t DURATION, --duration=DURATION
                       Total runtime of test
 -i INTERVAL, --interval=INTERVAL
                       How often to report results (internally, results still reported in aggregate at end)
                       How many parallel streams to run during the test
 -u, --udp             Use UDP instead of TCP testing
 -b BANDWIDTH, --bandwidth=BANDWIDTH
                       Bandwidth to rate limit the test to, supports SI
                       notation such as 1G
 -w WINDOW_SIZE, --window-size=WINDOW_SIZE
                       TCP window size to use for the test, supports SI notation such as 64M
 -m MSS, --mss=MSS     TCP maximum segment size
 -l BUFFER_LENGTH, --buffer-length=BUFFER_LENGTH
                       length of the buffer to read/write from
 --ip-tos=IP_TOS       IP type-of-service octet (integer)
                       Specify which IP version to use, 4 or 6
                       Use this as a local address for control and tests
 -O OMIT, --omit=OMIT  Number of seconds to omit from the start of the test
 --no-delay            Set TCP no-delay flag, disables Nagle's algorithm
                       Set TCP congestion control algorithm
 --zero-copy           Use a 'zero copy' method of sending data
                       Set the IPv6 flow label, implies --ip-version 6
                       Set's the sending side's CPU affinity
                       Set's the receiving's side's CPU affinity
 --reverse             Reverses the direction of the test.

The currently supported throughput tools are iperf2, iperf3, and nuttcp. iperf3 is the default. Note that not every tool supports every option. The following table summarizes tool specific option. Other pScheduler options are supported by all tools.

option iperf2 iperf3 nuttcp
–omit   X  
–congestion X X  
–zero-copy   X  

latency Tests

Latency tests support the following arguments:

pscheduler task latency --help
Usage: task [task-options] latency [test-options]
 -h, --help            show this help message and exit
 -s SOURCE, --source=SOURCE
                       The address of the entity sending packets in this test
                       The address of the source pScheduler node, if different
 -d DEST, --dest=DEST  The address of the entity receiving packets in this test
                       The address of the destination pScheduler node, if different
 -c PACKET_COUNT, --packet-count=PACKET_COUNT
                       The number of packets to send
                       The number of seconds to delay between sending packets
                       The number of seconds to wait before declaring a
                       packet lost
                       The size of padding to add to the packet in bytes
 -C CTRL_PORT, --ctrl-port=CTRL_PORT
                       The port to use for making a control connection to the
                       side acting as a server.
 -P DATA_PORTS, --data-ports=DATA_PORTS
                       The port range to use on the side of the test running
                       the client. At least two ports required.
 -T IP_TOS, --ip-tos=IP_TOS
                       The port range to use on the side of the test running
                       the client. At least two ports required.
                       Force an IP version when performing the test. Useful
                       when specifying hostnames as source or dest that may
                       map to both IPv4 and IPv6 addresses.
 -b BUCKET_WIDTH, --bucket-width=BUCKET_WIDTH
                       The bin size to use for histogram calculations. This
                       value is divided into the result as reported in
                       seconds and truncated to the nearest 2 decimal places.
 -f, --flip            In multi-participant mode, have the dest start the
                       client and request a reverse test. Useful in some
                       firewall and NAT environments.
 -R, --output-raw      Output individual packet statistics. This will
                       substantially increase the size of a successful

rtt Tests

RTT tests support the following arguments:

pscheduler task rtt --help
Usage: task [task-options] rtt [test-options]
 -h, --help            show this help message and exit
 --count=COUNT         Test count
 --dest=DEST           Destination host
                       Flow label
 --hostnames           Look up hostnames from IPs
 --no-hostnames        Don't look up hostnames from IPs
 --interval=INTERVAL   Time to wait between packets sent
                       IP version to use
 --source=SOURCE       Source address or interface
                       Source pScheduler node, if different
 --suppress-loopback   Suppress multicast loopback
                       Don't suppress multicast loopback
 --ip-tos=IP_TOS       IP type-of-service octet (integer)
 --length=LENGTH       Packet length
 --ttl=TTL             Time to live
 --deadline=DEADLINE   Deadline for all measurements to complete
 --timeout=TIMEOUT     Timeout for each round trip