-o OUTPUT, --output=OUTPUT

File to write processed output to (default standard out).

-D DATA_DIR, --data-dir=DATA_DIR

Directory to store data files in. Defaults to the current directory.

-i INPUT, --input=INPUT

File to read input from (instead of running tests). Input files can also be specified as unqualified arguments without using the -i switch.

-f FORMAT, --format=FORMAT

Select output format (plot, csv, org_table, stats). Default is no processed output (just writes the JSON data file).

-p PLOT, --plot=PLOT

Select which plot to output for the given test (implies -f plot). Use the --list-plots option to see available plots.

-t TITLE, --title-extra=TITLE

Text to add to plot title and data file name.

-n NOTE, --note=NOTE

Add arbitrary text as a note to be stored in the JSON data file (under the NOTE key in the metadata object).

-r RCFILE, --rcfile=RCFILE

Load configuration data from RCFILE (default ~/.flentrc). See section below for information on the rc file format.

-x, --extended-metadata

Collect extended metadata and store it with the data file. May include details of your machine you don’t want to distribute; see the section on the data format below.

--remote-metadata=HOSTNAME

Collect extended metadata from a remote host. HOSTNAME is passed verbatim to ssh, so can include hosts specified in ~/.ssh/config. Note that gathering the data can take some time, since it involves executing several remote commands. This option can be specified multiple times and implies --extended-metadata.

--gui

Run the flent GUI. All other options are used as defaults in the GUI, but can be changed once it is running. The GUI can also be started by running the flent-gui binary. For more information on the GUI, see the gui section.

--new-gui-instance

Start a new GUI instance. Otherwise, flent will try to connect to an already running GUI instance and have that load any new data files specified as arguments. Implies --gui when passed on the command line, but not when set in the rc file. Note that when multiple GUI instances are running, there is no guarantee as to which instance will get a subsequent open request (if run again without --new-gui-instance).

--gui-no-defer

Normally, the GUI defers redrawing plots until they are needed to avoid redrawing all open plots every time an option changes. This switch turns off that optimisation in favour of always redrawing everything straight away. This is useful when loading a bunch of plots from the command line and then wanting to flip through them without drawing delay.

-b BATCH_NAME, --batch-name=BATCH_NAME

Run test batch BATCH_NAME (must be specified in a batch file loaded by the --batch-file option). Can be supplied multiple times.

-B BATCH_FILE, --batch-file=BATCH_FILE

Load batch file BATCH_FILE. Can be specified multiple times, in which case the files will be combined (with identically-named sections being overridden by later files). See appropriate section below for an explanation of the batch file format.

--batch-override=key=value

Override parameter ’key’ in the batch config and set it to ’value’. The key name will be case folded to lower case. Can be specified multiple times.

--batch-dry-run

Dry batch run. Prints what would be done, but doesn’t actually run any tests.

--batch-verbose

Be verbose during batch run: Print all commands executed.

--batch-no-shuffle

Do not randomise the order of test runs within each batch.

--batch-repetitions=REPETITIONS

Shorthand for --batch-override 'repetitions=REPETITIONS’.

--batch-title=TITLE

Shorthand for --batch-override 'batch_title=TITLE’.

--batch-resume=DIR

Try to resume a previously interrupted batch run. The argument is the top-level output directory from the previous run.

This will attempt to find a data file in the resume directory and load the BATCH_TIME from the previous run from that and continue. The assumption is that the output directory and filenames are generated from the batch time, so that they will match with the previous run when the same time is used. Then, tests for which data files already exist will be skipped on this run. If the rest of the batch invocation is different from the one being resumed, results may not be what you want.

There's a check to ensure that the generated output path is a subdirectory of the resume directory, and the whole run will be aborted if it isn't.

-H HOST, --host=HOST

Host to connect to for tests. For tests that support it, multiple hosts can be specified by supplying this option multiple times. Hosts can also be specified as unqualified arguments; this parameter guarantees that the argument be interpreted as a host name (rather than being subject to auto-detection between input files, hostnames and test names).

--local-bind=IP

Local hostname or IP address to bind to (for test tools that support this). Can be specified multiple times for tests that connect to more than one host; if it is, it must be specified as many times as there are hosts.

--remote-host=idx=HOSTNAME

A remote hostname to connect to when starting a test. The idx is the runner index, which is assigned sequentially to each runner (and so it is not the same as the sequence of hostnames). Look for the 'IDX' key in SERIES_META for a test get the idx used here, but note that the idx assignment depends on the exact arguments to the test.

This works by simply prepending 'ssh HOSTNAME' to the runner command, so it relies on the same binaries being in the same places on both machines, and won't work for all runners.

This option can be specified multiple times to have multiple runners run on remote hosts.

-l LENGTH, --length=LENGTH

Base test length (some tests may add some time to this).

-s STEP_SIZE, --step-size=STEP_SIZE

Measurement data point step size.

-d DELAY, --delay=DELAY

Number of seconds to delay parts of test (such as bandwidth loaders).

-4, --ipv4

Use IPv4 for tests (some tests may ignore this).

-6, --ipv6

Use IPv6 for tests (some tests may ignore this).

--socket-timeout=SOCKET_TIMEOUT

Socket timeout (in seconds) used for UDP delay measurement, to prevent stalls on packet loss. Only enabled if the installed netperf version is detected to support this (requires SVN version of netperf).

For the default value, see the output of flent -h. The value of this parameter is an implicit upper bound on how long a round-trip time that can be measured. As such you may need to adjust it if you are experiencing latency above the default value. Set to 0 to disable.

--send-size=SEND_SIZE

Send size (in bytes) used for TCP tests. Netperf uses the socket buffer size by default, which if too large can cause spikes in the throughput results. Lowering this value will increase CPU usage but also improves the fidelity of the throughput results without having to decrease the socket buffer size.

Can be specified multiple times, with each value corresponding to a stream of a test. If only specified once, the same value will be applied to all flows.

--test-parameter=key=value

Arbitrary test parameter in key=value format. Key will be case folded to lower case. The values are stored with the results metadata, and so can be used for storing arbitrary information relevant for a particular test run.

In addition to serving as simple metadata, the test parameters can also affect the behaviour of some test configurations. See the tests section for information on these.

This option can be specified multiple times to set multiple test parameters.

--swap-up-down

Switch upstream and downstream directions for data transfer. This means that ’upload’ will become ’download’ and vice versa. Works by exchanging netperf TCP_MAERTS and TCP_STREAM parameters, so only works for tests that employ these as their data transfer, and only for the TCP streams.

--socket-stats

Parse socket stats during test. This will capture and parse socket statistics for all TCP upload flows during a test, adding TCP cwnd and RTT values to the test data. Requires the 'ss' utility to be present on the system, and can fail if there are too many simultaneous upload flows; which is why this option is not enabled by default.

--marking-name

Define a new symbolic name that can be used when specifying flow markings using the 'markings' test parameter. This can be used to make it easier to specify custom diffserv markings on flows by using symbolic names for each marking value instead of the hex codes. Values specified here will be used in addition to the common values (listed below), and cannot override the built-in names. Names will be case-folded when matching.

The list of symbolic markings natively supported, along with their hex expansions, are:

AF11: 0x28    CS0: 0x00
AF12: 0x30    CS1: 0x20
AF13: 0x38    CS2: 0x40
AF21: 0x48    CS3: 0x60
AF22: 0x50    CS4: 0x80
AF23: 0x58    CS5: 0xa0
AF31: 0x68    CS6: 0xc0
AF32: 0x70    CS7: 0xe0
AF33: 0x78    EF:  0xb8
AF41: 0x88
AF42: 0x90
AF43: 0x98

Note that the hexadecimal values denote the value of the full ToS byte (including the two ECN bits), so they need to be right-shifted by two bits to get the corresponding diffserv code points.

--label-x=LABEL

--label-y=LABEL

Override the figure axis labels. Can be specified twice, corresponding to figures with multiple axes.

-I, --invert-latency-y

Invert latency data series axis (typically the Y-axis), making plots show ’better' values upwards.

-z, --zero-y

Always start Y axis of plot at zero, instead of autoscaling the axis. Autoscaling is still enabled for the upper bound. This also disables log scale if enabled.

--log-scale={log2,log10}

Use the specified logarithmic scale on plots.

--norm-factor=FACTOR

Data normalisation factor. Divide all data points by this value. Can be specified multiple times, in which case each value corresponds to a data series.

--bounds-x=BOUNDS

--bounds-y=BOUNDS

Specify bounds of the plot axes. If specifying one number, that will become the upper bound. Specify two numbers separated by a comma to specify both upper and lower bounds. To specify just the lower bound, add a comma afterwards. Can be specified twice, corresponding to figures with multiple axes.

-S, --scale-mode

Treat file names (except for the first one) passed as unqualified arguments as if passed as --scale-data (default as if passed as --input).

--concatenate

Concatenate multiple result sets into one data series. This means that each data file will have its time axis shifted by the preceding series duration and appended to the first data set specified. Only works for data sets from the same test, obviously.

--absolute-time

Plot data points with absolute UNIX time on the x-axis. This requires the absolute starting time for the test run to be stored in the data file, and so it won’t work with data files that predates this feature.

--subplot-combine

When plotting multiple data series, plot each one on a separate subplot instead of combining them into one plot. This mode is not supported for all plot types, and only works when --scale-mode is disabled.

--skip-missing-series

Skip missing series entirely from bar plots, instead of leaving an empty space for it.

--no-print-n

Do not print the number of data points on combined plots. When using plot types that combines results from several test runs, the number of data series in each combined data point is normally added after the series name, (n=X) for X data series. This option turns that off.

--no-annotation

Exclude annotation with hostnames, time and test length from plots.

--figure-note=NOTE, --fig-note=NOTE

Add a note (arbitrary text) to the bottom-left of the figure.

--no-title

Exclude title from plots.

--override-title=TITLE

Override plot title with this string. Completely discards the configured title (from the test configuration), as well as the title stored in the data set, and replaces it with the value supplied here. This is useful to override the plot title at the time of plotting, for instance to add a title to an aggregate plot from several data series. When this parameter is specified, --no-title has no effect.

--no-labels

Hides tick labels from box and bar plots.

--no-markers

Don’t use line markers to differentiate data series on plots.

--no-legend

Exclude legend from plots.

--horizontal-legend

Place a horizontal legend below the plot instead of a vertical one next to it. Doesn't always work well if there are too many items in the legend.

--legend-title=LEGEND_TITLE

Override legend title on plot.

--legend-placement=LEGEND_PLACEMENT

Control legend placement. Enabling this option will place the legend inside the plot at the specified location. Can be one of 'best', 'upper right', 'upper left', 'lower left', 'lower right', 'right', 'center left', 'center right', 'lower center', 'upper center' or 'center'.

--legend-columns=LEGEND_COLUMNS

Set the number of columns in the legend.

--reverse-legend

Reverse the order of items in the legend. This can be useful to make the legend order match the data series in some cases.

--filter-legend

Filter legend labels by removing the longest common substring from all entries. This is not particularly smart, so use with care.

--replace-legend=src=dest

Replace 'src' with 'dst' in legends. Can be specified multiple times.

--filter-regexp=REGEXP

Filter the plot legend by the supplied regular expression. Note that for combining several plot results, the regular expression is also applied before the grouping logic, meaning that a too wide filter can mess up the grouping.

--override-label=LABEL

Override dataset label. Can be specified multiple times when multiple datasets are being plotted, in which case the order of labels corresponds to the order of datasets.

Like --override-title, this is applied at the time of plotting.

--filter-series=SERIES

Filter out specified series from plot. Can be specified multiple times.

--split-group=LABEL

Split data sets into groups when creating box plots. Specify this option multiple times to define the new groups; the value of each option is the group name.

Say you're plotting nine datasets which are really testing two variables with three values each. In this case, it can be useful to have the box plot of the results be split into three parts (corresponding to the values of one variable) with each three boxes in each of them (corresponding to the values of the second variable). This option makes this possible; simply specify it three times with the labels to be used for the three groups.

A constraint on this option is that the number of datasets being plotted must be divisible by the number of groups.

--colours=COLOURS

Comma-separated list of colours to be used for the plot colour cycle. Can be specified in any format understood by matplotlib (including HTML hex values prefixed with a #).

Yes, this option uses British spelling. No, American spelling is not supported.

--override-colour-mode=MODE

Override colour_mode attribute. This changes the way colours are assigned to bar plots. The default is 'groups' which assigns a separate colour to each group of data series. The alternative is 'series' which assigns a separate colour to each series, repeating them for each data group.

--override-group-by=GROUP

Override the group_by setting for combination plots. This is useful to, for instance, switch to splitting up combined data sets by batch run instead of by file name.

--combine-save-dir=DIRNAME

When doing a combination plot save the intermediate data to DIRNAME. This can then be used for subsequent plotting to avoid having to load all the source data files again on each plot.

--figure-width=FIG_WIDTH

Figure width in inches. Used when saving plots to file and for default size of the interactive plot window.

--figure-height=FIG_HEIGHT

Figure height in inches. Used when saving plots to file and for default size of the interactive plot window.

--figure-dpi=FIG_DPI

Figure DPI. Used when saving plots to raster format files.

--fallback-layout

Use the fallback layout engine (tight_layout built in to matplotlib). Use this if text is cut off on saved figures. The downside to the fallback engine is that the size of the figure (as specified by --figure-width and --figure-height) is no longer kept constant.)

--no-matplotlibrc

Don’t load included matplotlibrc values. Use this if autodetection of custom matplotlibrc fails and flent is inadvertently overriding rc values.

--no-hover-highlight

Don't highlight data series on hover in interactive plot views. Use this if redrawing is too slow, or the highlighting is undesired for other reasons.

--scale-data=SCALE_DATA

Additional data files to consider when scaling the plot axes (for plotting several plots with identical axes). Note, this displays only the first data set, but with axis scaling taking into account the additional data sets. Can be supplied multiple times; see also --scale-mode.

--control-host=HOST

Hostname for the test control connection (for test tools that support this). Default: First hostname of test target.

When running tests that uses D-ITG as a test tool (such as the voip-* tests), this switch controls where flent will look for the D-ITG control server (see section below on running tests with D-ITG). For Netperf-based tests, this option is passed to Netperf to control where to point the control connection. This is useful to, for instance, to run the control server communication over a separate control network so as to not interfere with test traffic.

There is also a per-flow setting for this for tests that connect to multiple hosts; see the control_hosts test parameter in tests. If both are set, the per-flow setting takes precedence for those tests that use it.

--control-local-bind=IP

Local hostname or IP to bind control connection to (for test tools that support it; currently netperf). If not supplied, the value for --local-bind will be used. Note that if this value is passed but --local-bind is not, netperf will use the value specified here to bind the data connections to as well.

--netperf-control-port=PORT

Port for Netperf control server. Default: 12865.

--ditg-control-port=PORT

Port for D-ITG control server. Default: 8000.

--ditg-control-secret=SECRET

Secret for D-ITG control server authentication. Default: ’’.

--http-getter-urllist=FILENAME

When running HTTP tests, the http-getter tool is used to fetch URLs (see https://github.com/tohojo/http-getter). This option specifies the filename containing the list of HTTP URLs to get. Can also be a URL, which will then be downloaded as part of each test iteration. If not specified, this is set to http://<hostname>/filelist.txt where <hostname> is the first test hostname.

--http-getter-dns-servers=DNS_SERVERS

DNS servers to use for http-getter lookups. Format is host[:port][,host[:port]]... This option will only work if libcurl supports it (needs to be built with the ares resolver). Default is none (use the system resolver).

--http-getter-timeout=MILLISECONDS

Timeout for HTTP connections. Default is to use the test length.

--http-getter-workers=NUMBER

Number of workers to use for getting HTTP urls. Default is 4.

-L LOG_FILE, --log-file=LOG_FILE

Write debug log (test program output) to log file.

--list-tests

List available tests and exit.

--list-plots

List available plots for selected test and exit.

-V, --version

Show Flent version information and exit.

-v, --verbose

Enable verbose logging to console.

-q, --quiet

Disable normal logging to console (and only log warnings and errors).

--debug-error

Print full exception backtraces to console.

-h, --help

Show usage help message and exit.

upload_streams

download_streams

bidir_streams

These set the number of streams for the tests that are configurable. The tcp_nup, tcp_ndown and rrul_be_nflows tests understand upload_streams and download_streams, while the rrul_var test understands bidir_streams. If any of these parameter is set to the special value num_cpus the number of streams will be set to the number of CPUs on the system (if this information is available).

tcp_cong_control

Set the congestion control used for TCP flows, for platforms that supports setting it. This can be specified as a simple string to set the same value for upstream and downstream, or two comma-separated values to set it separately for the upstream and downstream directions. On Linux, any value in the sysctl net.ipv4.tcp_allowed_congestion_control can be used.

If a congestion control is specified that is not available on the system running the test, setting it will simply fail. In addition, some tests override the congestion control for one or more flows. The actual congestion control used is stored in the CONG_CONTROL per-test metadata field.

udp_bandwidth

udp_bandwidths

udp_pktsize

udp_pktsizes

This sets the bandwidth and packet size of each UDP stream in the udp_* tests. The option is passed to iperf so can be in any syntax the iperf understands (e.g. 20M for 20 Mbps).

When running multiple UDP streams use the plural versions of the options (udp_bandwidths and udp_pktsizes) to specify individual per-stream values (comma-separated per stream), or the singular versions to specify the same value for all streams.

burst_length

burst_ports

burst_psize

burst_tos

These set the length, number of ports to use, packet size and TOS value for the packet bursts generated in the burst* tests.

cpu_stats_hosts

netstat_hosts

qdisc_stats_hosts

wifi_stats_hosts

These set hostnames to gather statistics from from during the test. The hostnames are passed to SSH, so can be anything understood by SSH (including using username@host syntax, or using hosts defined in ~/.ssh/config). This will attempt to run remote commands on these hosts to gather the required statistics, so passwordless login has to be enabled for. Multiple hostnames can be specified, separated by commas.

CPU stats and netstat output is global to the machine being connected to. The qdisc and WiFi stats need extra parameters to work. These are qdisc_stats_interfaces, wifi_stats_interfaces and wifi_stats_stations. The two former specify which interfaces to gather statistics from. These are paired with the hostnames, and so must contain the same number of elements (also comma-separated) as the _hosts variables. To specify multiple interfaces on the same host, duplicate the hostname. The wifi_stats_stations parameter specifies MAC addresses of stations to gather statistics for. This list is the same for all hosts, but only stations present in debugfs on each host are actually captured.

The qdisc stats gather statistics output from tc -s, while the WiFi stats gather statistics from debugfs. These are gathered by looping in a shell script; however, for better performance, the tc_iterate and wifistats_iterate programmes available in the misc/ directory of the source code tarball can be installed. On low-powered systems this can be critical to get correct statistics. The helper programmes are packaged for LEDE/OpenWrt in the flent-tools package.

ping_hosts

ping_local_binds

ping_labels

These are used to define one or more extra host names that will receive a ping flow while a test is run. The ping_hosts variable simply specifies hostnames to ping (several can be specified by separating them with commas). The ping_local_binds variable sets local IP address(es) to bind to for the extra ping flows. If specified, it must contain the same number of local addresses as the number of ping hosts. The same local address can be specified multiple times, however. The ping_labels variable is used to label each of the ping flows; if not specified, Flent will create a default label based on the target hostname for each flow.

voip_host

voip_local_bind

voip_control_host

voip_marking

Similar to the ping variants above, these parameters specify a hostname that will receive a VoIP test. However, unlike the ping parameters, only one hostname can be specified for VoIP tests, and that end-host needs to have either D-ITG (and the control server) or the IRTT server running. The marking setting controls which DiffServ marking is applied to the VoIP flow and defaults to no marking being set.

control_hosts

Hostnames to use for the control connections for the rtt_fair* tests. Comma-separated. If specified, it must contain as many hostnames as the number of target hostnames specified for the test.

markings

labels

Flow markings to use for each of the flows in the rtt_fair* tests. Comma-separated values of markings understood by Netperf (such as "CS0"). Only supports setting the same marking on both the upstream and downstream packets of each flow (so no "CS0,CS0" setting as can be used for Netperf). If not set, defaults to CS0 (best effort). If set, each value corresponds to a flow, and any extra flows will be set to CS0. By default each flow will be labelled according to its marking; to override these labels, use the labels parameter.

stream_delays

Specify a per-stream delay (in seconds) for the different streams started up by a test. Use commas to separate values for the different streams. This can be used to create tests with staggered start times, for example to test TCP flow startup convergence times. What exactly constitutes a stream depends on the test. For example, the rtt_fair* tests considers each hostname a stream, whether or not there is one or two flows going to that host.

version

The file format version as an integer.

x_values

An array of the x values for the test data (typically the time values for timeseries data).

results

A JSON object containing the result data series. The keys are the data series names; the value for each key is an array of y values for that data series. The data array has the same length as the x_values array, but there may be missing data points (signified by null values).

metadata

An object containing various data points about the test run. The metadata values are read in as configuration parameters when the data set is loaded in for further processing. Not all tests use all the parameters, but they are saved anyway.

raw_values

An array of objects for each data series. Each element of the array contains the raw values as parsed from the test tool corresponding to that data series.

NAME

The test name.

TITLE

Any extra title specified by the --title-extra parameter when the test was run.

HOSTS

List of the server hostnames connected to during the test.

LOCAL_HOST

The hostname of the machine that ran the test.

LENGTH

Test length in seconds, as specified by the --length parameter.

TOTAL_LENGTH

Actual data series length, after the test has added time to the LENGTH.

STEP_SIZE

Time step size granularity.

TIME

ISO timestamp of the time the test was initiated.

NOTE

Arbitrary text as entered with the --note switch when the test was run.

FLENT_VERSION

Version of Flent that generated the data file.

IP_VERSION

IP version used to run test (as specified by command line parameters, or auto-detected from getaddrinfo() if unspecified).

KERNEL_NAME

The kernel name as reported by uname -s.

KERNEL_RELEASE

The kernel release as reported by uname -r.

MODULE_VERSIONS

The sha1sum of certain interesting Linux kernel modules, if available. Can be used to match test data to specific code versions, if the kernel build is instrumented to, e.g., set the build ID to a git revision.

SYSCTLS

The values of several networking-related sysctls on the host (if available; Linux only).

EGRESS_INFO

Interface name, qdisc, offload, driver and BQL configuration of the interface used to reach the test target. This requires that the ip binary is present on Linux, but can be extracted from route on BSD. Qdisc information requires the tc binary to be present, and offload information requires ethtool.

If the --remote-metadata is used, the extended metadata info is gathered for each of the hostnames specified. This is gathered under the REMOTE_METADATA key in the metadata object, keyed by the hostname values passed to --remote-metadata. Additionally, the REMOTE_METADATA object will contain an object called INGRESS_INFO which is a duplicate of EGRESS_INFO, but with the destination IP exchanged for the source address of the host running flent. The assumption here is that --remote-metadata is used to capture metadata of a router known to be in the test path, in which case INGRESS_INFO will contain information about the reverse path from the router (which is ingress from the point of view of the host running flent). If the host being queried for remote metadata is off the path, the contents of INGRESS_INFO will probably be the same as that of EGRESS_INFO .

IP_ADDRS

IP addresses assigned to the machine running flent.

GATEWAYS

IP addresses of all detected default gateways on the system, and the interfaces they are reachable through. Only available if the netstat binary is present on the system.

EGRESS_INFO

In the EGRESS_INFO key, the IP address of the next-hop router and the interface MAC address are added if extended metadata is enabled.