Test and Tool Reference

Introduction

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.

Note

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

clock

Description

Measure the clock difference between hosts

Tools

psclock

disk-to-disk

Description

Network testing of throughput and Read/Write speeds

Tools

curl, globus

dns

Description

Measure DNS transaction time

Tools

dnspy

http

Description

Measure HTTP response time

Tools

psurl

latency

Description

Measure one-way latency and associated statistics between hosts

Tools

owping

latencybg

Description

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

Tools

powstream

rtt

Description

Measure the round trip time and related statistics between hosts

Tools

ping

simplestream

Description

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

Tools

simplestreamer

throughput

Description

A test to measure the observed speed of a data transfer and associated statistics between two endpoints

Tools

iperf3, iperf2, nuttcp

s3throughput

Description

A test to measure the throughput of S3 web service storage

Tools

s3-benchmark

trace

Description

Trace the path between IP hosts

Tools

traceroute, tracepath, paris-traceroute

Test Classifications

Each test classified in one of four categories that determines what other tests can be run in parallel:

  1. Exclusive - An example is a throughput task. If you have very little whitespace in this category then you may have difficulty finding a timeslot for new tests. These test can run in parallel only with background tests.

  2. Normal - An example is a task with a test type of latency.

  3. Background Single-Result - Background tests that produce single result. Example test types include rtt and trace or clock. These tests can run in parallel with anything else.

  4. Background Multi-Result - Background tests that produce multiple (streaming) results. Example test type is latencybg. It is not uncommon to have this column look almost entirely solid if you have latencybg tasks since they run continuously. These tests can run in parallel with anything else.

  5. Non-Starting - These are runs that could not find a time-slot. A very important note, and common point of confusion, is that the time shown is the earliest possible time in the slot it was trying to schedule. This IS NOT the time when the scheduler tried to find a slot, failed and labelled it as a non-start. pScheduler uses a schedule horizon so likely attempted to schedule the run 24 hours in advance. A large number of runs in this category may be the indication of a busy host where it is difficult for exclusive tasks to find a timeslot.

  6. Preempted - These runs were preempted by another with higher priority.

You may visualize different types of tests using pscheduler plot-schedule command. See also Visualizing the Schedule with pscheduler plot-schedule.

You can know which scheduling class a test belongs to by running the pscheduler plugins tests command.

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
 --source-node=SOURCE_NODE
                       pScheduler node on sending host, if different
 -d DESTINATION, --dest=DESTINATION, --destination=DESTINATION
                       Receiving host
 --dest-node=DEST_NODE
                       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)
 -P PARALLEL, --parallel=PARALLEL
                       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)
 --ip-version=IP_VERSION
                       Specify which IP version to use, 4 or 6
 -B LOCAL_ADDRESS, --local-address=LOCAL_ADDRESS
                       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
 --congestion=CONGESTION
                       Set TCP congestion control algorithm
 --zero-copy           Use a 'zero copy' method of sending data
 --flow-label=FLOW_LABEL
                       Set the IPv6 flow label, implies --ip-version 6
 --client-cpu-affinity=CLIENT_CPU_AFFINITY
                       Set's the sending side's CPU affinity
 --server-cpu-affinity=SERVER_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
 --source-node=SOURCE_NODE
                       The address of the source pScheduler node, if different
 -d DEST, --dest=DEST  The address of the entity receiving packets in this test
 --dest-node=DEST_NODE
                       The address of the destination pScheduler node, if different
 -c PACKET_COUNT, --packet-count=PACKET_COUNT
                       The number of packets to send
 -i PACKET_INTERVAL, --packet-interval=PACKET_INTERVAL
                       The number of seconds to delay between sending packets
 -L PACKET_TIMEOUT, --packet-timeout=PACKET_TIMEOUT
                       The number of seconds to wait before declaring a
                       packet lost
 -p PACKET_PADDING, --packet-padding=PACKET_PADDING
                       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.
 --ip-version=IP_VERSION
                       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
                       result.

The currently supported latency tools are owping (used by default) and twping. When using twping the destination (-d) can be any network device acting as a TWAMP Server and Session-Reflector, see RFC-5357 for more details (TWAMP Light is currently not supported by perfSONAR).

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
 -c COUNT, --count=COUNT
                       Test count
 -d DEST, --dest=DEST  Destination host
 --flow-label=FLOW_LABEL
                       Flow label
 --fragment            Allow packet fragmentation
 --no-fragment         Don't allow packet fragmentation
 --hostnames           Look up hostnames from IPs
 --no-hostnames        Don't look up hostnames from IPs
 -i INTERVAL, --interval=INTERVAL
                       Time to wait between packets sent
 --ip-version=IP_VERSION
                       IP version to use
 -s SOURCE, --source=SOURCE
                       Source address or interface
 --source-node=SOURCE_NODE
                       Source pScheduler node, if different
 --suppress-loopback   Suppress multicast loopback
 --no-suppress-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
 --protocol=PROTOCOL   Protocol used to measure round trip time

The currently 2 supported protocols for RTT measurements are icmp and twamp. When using twamp you need to make sure that the destination (-d) is a TWAMP Server and Session-Reflector, see RFC-5357 for more details (TWAMP Light is currently not supported by perfSONAR).

trace Tests

Trace tests support the following arguments:

pscheduler task trace --help
Usage: task [task-options] trace [test-options]

-h, --help                  show this help message and exit
--algorithm=ALGORITHM       Trace algorithm
--as                        Find AS for each hop
--no-as                     Don't find AS for each hop
-d DEST, --dest=DEST        Destination host
--ip-version=IPVERSION      IP Version
--length=LENGTH             Packet length
--probe-type=PROBETYPE      Probe type
--fragment                  Allow fragmentation
--no-fragment               Don't allow fragmentation
--first-ttl=FIRSTTTL        First TTL value
-s SOURCE, --source=SOURCE  Source address
--source-node=SOURCE_NODE   Source address
--hops=HOPS                 Maximum number of hops
--queries=QUERIES           Queries sent per hop
--hostnames                 Resolve IPs to host names
--no-hostnames              Don't resolve IPs to host names
--dest-port=DESTPORT        Destination port
--wait=WAIT                 Wait time
--sendwait=SENDWAIT         Wait time between probes
--ip-tos=IP_TOS             IP type-of-service octet (integer)

The currently supported trace tools are traceroute, tracepath, paris-traceroute. traceroute is the default.

Note

Please note that if you have a server that has more then one network interface the tracepath tool does not provide an option to select the outgoing source interface.

http Tests

HTTP tests support the following arguments:

pscheduler task http --help
Usage: task [task-options] http [test-options]

-h, --help             show this help message and exit
--url=URL              URL to query
--parse=PARSE          String to parse for
--host=HOST            Host to run the test
--host-node=HOST_NODE  Host to run the test
--timeout=TIMEOUT      Timeout for each query attempt

dns Tests

DNS tests support the following arguments:

pscheduler task dns --help
Usage: task [task-options] dns [test-options]

-h, --help               show this help message and exit
--host=HOST              Host to run the test
--host-node=HOST_NODE    Host to run the test
--nameserver=NAMESERVER  Nameserver to query
--record=RECORD          Record type to query  (One of a, aaaa, ns, cname, soa, ptr, mx and txt)
--query=QUERY            String to query
--timeout=TIMEOUT        Timeout for each query attempt