Testing¶
It is possible to test Open vSwitch using both tooling provided with Open vSwitch and using a variety of third party tooling.
Built-in Tooling¶
Open vSwitch provides a number of different test suites and other tooling for validating basic functionality of OVS. Before running any of the tests described here, you must bootstrap, configure and build Open vSwitch as described in Open vSwitch on Linux, FreeBSD and NetBSD. You do not need to install Open vSwitch or to build or load the kernel module to run these test suites. You do not need supervisor privilege to run these test suites.
Unit Tests¶
Open vSwitch includes a suite of self-tests. Before you submit patches upstream, we advise that you run the tests and ensure that they pass. If you add new features to Open vSwitch, then adding tests for those features will ensure your features don’t break as developers modify other areas of Open vSwitch.
To run all the unit tests in Open vSwitch, one at a time, run:
$ make check
This takes under 5 minutes on a modern desktop system.
To run all the unit tests in Open vSwitch in parallel, run:
$ make check TESTSUITEFLAGS=-j8
You can run up to eight threads. This takes under a minute on a modern 4-core desktop system.
To see a list of all the available tests, run:
$ make check TESTSUITEFLAGS=--list
To run only a subset of tests, e.g. test 123 and tests 477 through 484, run:
$ make check TESTSUITEFLAGS='123 477-484'
Tests do not have inter-dependencies, so you may run any subset.
To run tests matching a keyword, e.g. ovsdb, run:
$ make check TESTSUITEFLAGS='-k ovsdb'
To see a complete list of test options, run:
$ make check TESTSUITEFLAGS=--help
The results of a testing run are reported in tests/testsuite.log. Report
test failures as bugs and include the testsuite.log in your report.
Note
Sometimes a few tests may fail on some runs but not others. This is usually a
bug in the testsuite, not a bug in Open vSwitch itself. If you find that a
test fails intermittently, please report it, since the developers may not
have noticed. You can make the testsuite automatically rerun tests that fail,
by adding RECHECK=yes to the make command line, e.g.:
$ make check TESTSUITEFLAGS=-j8 RECHECK=yes
Debugging unit tests¶
To initiate debugging from artifacts generated from make check run, set the
OVS_PAUSE_TEST environment variable to 1. For example, to run test case
139 and pause on error:
$ OVS_PAUSE_TEST=1 make check TESTSUITEFLAGS='-v 139'
When error occurs, above command would display something like this:
Set environment variable to use various ovs utilities
export OVS_RUNDIR=<dir>/ovs/_build-gcc/tests/testsuite.dir/0139
Press ENTER to continue:
And from another window, one can execute ovs-xxx commands like:
export OVS_RUNDIR=/opt/vdasari/Developer/ovs/_build-gcc/tests/testsuite.dir/0139
$ ovs-ofctl dump-ports br0
.
.
Once done with investigation, press ENTER to perform cleanup operation.
Coverage¶
If the build was configured with --enable-coverage and the lcov utility
is installed, you can run the testsuite and generate a code coverage report by
using the check-lcov target:
$ make check-lcov
All the same options are available via TESTSUITEFLAGS. For example:
$ make check-lcov TESTSUITEFLAGS='-j8 -k ovsdb'
Valgrind¶
If you have valgrind installed, you can run the testsuite under
valgrind by using the check-valgrind target:
$ make check-valgrind
When you do this, the “valgrind” results for test <N> are reported in files
named tests/testsuite.dir/<N>/valgrind.*.
To test the testsuite of kernel datapath under valgrind, you can use the
check-kernel-valgrind target and find the “valgrind” results under
directory tests/system-kmod-testsuite.dir/.
All the same options are available via TESTSUITEFLAGS.
Hint
You may find that the valgrind results are easier to interpret if you put
-q in ~/.valgrindrc, since that reduces the amount of output.
OFTest¶
OFTest is an OpenFlow protocol testing suite. Open vSwitch includes a Makefile target to run OFTest with Open vSwitch in “dummy mode”. In this mode of testing, no packets travel across physical or virtual networks. Instead, Unix domain sockets stand in as simulated networks. This simulation is imperfect, but it is much easier to set up, does not require extra physical or virtual hardware, and does not require supervisor privileges.
To run OFTest with Open vSwitch, you must obtain a copy of OFTest and install its prerequisites. You need a copy of OFTest that includes commit 406614846c5 (make ovs-dummy platform work again). This commit was merged into the OFTest repository on Feb 1, 2013, so any copy of OFTest more recent than that should work. Testing OVS in dummy mode does not require root privilege, so you may ignore that requirement.
Optionally, add the top-level OFTest directory (containing the oft program)
to your $PATH. This slightly simplifies running OFTest later.
To run OFTest in dummy mode, run the following command from your Open vSwitch build directory:
$ make check-oftest OFT=<oft-binary>
where <oft-binary> is the absolute path to the oft program in OFTest.
If you added “oft” to your $PATH, you may omit the OFT variable
assignment
By default, check-oftest passes oft just enough options to enable dummy
mode. You can use OFTFLAGS to pass additional options. For example, to run
just the basic.Echo test instead of all tests (the default) and enable
verbose logging, run:
$ make check-oftest OFT=<oft-binary> OFTFLAGS='--verbose -T basic.Echo'
If you use OFTest that does not include commit 4d1f3eb2c792 (oft: change default port to 6653), merged into the OFTest repository in October 2013, then you need to add an option to use the IETF-assigned controller port:
$ make check-oftest OFT=<oft-binary> OFTFLAGS='--port=6653'
Interpret OFTest results cautiously. Open vSwitch can fail a given test in OFTest for many reasons, including bugs in Open vSwitch, bugs in OFTest, bugs in the “dummy mode” integration, and differing interpretations of the OpenFlow standard and other standards.
Note
Open vSwitch has not been validated against OFTest. Report test failures that you believe to represent bugs in Open vSwitch. Include the precise versions of Open vSwitch and OFTest in your bug report, plus any other information needed to reproduce the problem.
Ryu¶
Ryu is an OpenFlow controller written in Python that includes an extensive OpenFlow testsuite. Open vSwitch includes a Makefile target to run Ryu in “dummy mode”. See OFTest above for an explanation of dummy mode.
To run Ryu tests with Open vSwitch, first read and follow the instructions under Testing above. Second, obtain a copy of Ryu, install its prerequisites, and build it. You do not need to install Ryu (some of the tests do not get installed, so it does not help).
To run Ryu tests, run the following command from your Open vSwitch build directory:
$ make check-ryu RYUDIR=<ryu-source-dir>
where <ryu-source-dir> is the absolute path to the root of the Ryu source
distribution. The default <ryu-source-dir> is $srcdir/../ryu
where $srcdir is your Open vSwitch source directory. If this is correct,
omit RYUDIR
Note
Open vSwitch has not been validated against Ryu. Report test failures that you believe to represent bugs in Open vSwitch. Include the precise versions of Open vSwitch and Ryu in your bug report, plus any other information needed to reproduce the problem.
Datapath testing¶
Open vSwitch includes a suite of tests specifically for datapath functionality, which can be run against the userspace or kernel datapaths. If you are developing datapath features, it is recommended that you use these tests and build upon them to verify your implementation.
The datapath tests make some assumptions about the environment. They must be run under root privileges on a Linux system with support for network namespaces.
Make sure, no other Open vSwitch instance is running on the test suite. These tests may take several minutes to complete, and cannot be run in parallel.
Userspace datapath¶
To invoke the datapath testsuite with the userspace datapath, run:
$ make check-system-userspace
The results of the testsuite are in tests/system-userspace-testsuite.dir.
All the features documented under Unit Tests are available for the userspace datapath testsuite.
Userspace datapath with DPDK¶
To test Open vSwitch with DPDK (i.e., the build was configured with
--with-dpdk, the DPDK is installed), run the testsuite and generate
a report by using the check-dpdk target:
# make check-dpdk
or if you are not a root, but a sudo user:
$ sudo -E make check-dpdk
To see a list of all the available tests, run:
# make check-dpdk TESTSUITEFLAGS=--list
These tests support a DPDK supported NIC. The tests operate on a wider set of environments, for instance, when a virtual port is used. Moreover you need to have root privileges to load the required modules and to bind a PCI device to the DPDK-compatible driver.
The phy test will skip if no suitable PCI device is found. It is possible to select which PCI device is used for this test by setting the DPDK_PCI_ADDR environment variable, which is especially useful when testing with a mlx5 device:
# DPDK_PCI_ADDR=0000:82:00.0 make check-dpdk
All tests are skipped if no hugepages are configured. User must look into the DPDK manual to figure out how to Configure hugepages.
All the features documented under Unit Tests are available for the DPDK testsuite.
Userspace datapath with DPDK offload¶
To invoke the userspace datapath tests with DPDK and its rte_flow offload, the same prerequisites apply as above. In addition, six Virtual Function (VF) interfaces must be preconfigured on a single Physical Function (PF) that supports rte_flow hardware offload.
This is an example on how to set this up for an NVIDIA blade on port
ens2f0np0:
OVS_PF_PCI=$(basename $(readlink /sys/class/net/ens2f0np0/device))
echo 0 > /sys/bus/pci/devices/$OVS_PF_PCI/sriov_numvfs
devlink dev eswitch set pci/$OVS_PF_PCI mode switchdev
echo 6 > /sys/bus/pci/devices/$OVS_PF_PCI/sriov_numvfs
This PF’s PCI ID needs to be passed with the OVS_PF_PCI variable. To invoke the DPDK offloads testsuite with the userspace datapath, run:
make check-dpdk-offloads OVS_PF_PCI=0000:17:00.0
Note
This has only been tested on NVIDIA blades due to the limited availability of other blades that support rte_flow.
Kernel datapath¶
Make targets are also provided for testing the Linux kernel module. Note that these tests operate by inserting modules into the running Linux kernel, so if the tests are able to trigger a bug in the OVS kernel module or in the upstream kernel then the kernel may panic.
To run the testsuite against the kernel module which is currently installed on your system, run:
$ make check-kernel
All the features documented under Unit Tests are available for the kernel datapath testsuite.
Note
Many of the kernel tests are dependent on the utilities present in the iproute2 package, especially the ‘ip’ command. If there are many otherwise unexplained errors it may be necessary to update the iproute2 package utilities on the system. It is beyond the scope of this documentation to explain all that is necessary to build and install an updated iproute2 utilities package. The package is available from the Linux kernel organization open source git repositories.
https://git.kernel.org/pub/scm/network/iproute2/iproute2.git
It is also possible to run retis capture along with the check-kernel and check-offloads tests by setting OVS_TEST_WITH_RETIS environment variable to ‘yes’. This can be useful for debugging the test cases. For example, the following command can be used to run the test 167 under retis:
$ make check-kernel OVS_TEST_WITH_RETIS=yes TESTSUITEFLAGS='167 -d'
After the test is completed, the following data will be available in the test directory:
retis.err - standard error stream of the retis collect.
retis.log - standard output of the retis collect, contains all captured events in the order they appeared.
retis.data - raw events collected by retis, retis sort or other commands can be used on this file for further analysis.
retis.sorted - text file containing the output of retis sort executed on the retis.data, for convenience.
Requires retis version 1.5 or newer and enabling support for User Statically-Defined Tracing (USDT) probes.
Static Code Analysis¶
Static Analysis is a method of debugging Software by examining code rather than actually executing it. This can be done through ‘scan-build’ commandline utility which internally uses clang (or) gcc to compile the code and also invokes a static analyzer to do the code analysis. At the end of the build, the reports are aggregated in to a common folder and can later be analyzed using ‘scan-view’.
Open vSwitch includes a Makefile target to trigger static code analysis:
$ ./boot.sh
$ ./configure CC=clang # clang
# or
$ ./configure CC=gcc CFLAGS="-std=gnu99" # gcc
$ make clang-analyze
You should invoke scan-view to view analysis results. The last line of output
from clang-analyze will list the command (containing results directory)
that you should invoke to view the results on a browser.
ViNePerf¶
The ViNePerf project, formerly known as VswitchPerf or vsperf, aims to develop a vSwitch test framework that can be used to validate the suitability of different vSwitch implementations in a telco deployment environment. More information can be found on the Anuket project wiki.