Testing in rdma-core

rdma-core now offers an infrastructure for quick and easy additions of feature- specific tests.

Design

Resources Management

BaseResources class is the basic objects aggregator available. It includes a Context and a PD. Inheriting from it is TrafficResources class, which also holds a MR, CQ and QP, making it enough to support loopback traffic testing. It exposes methods for creation of these objects which can be overridden by inheriting classes. Inheriting from TrafficResources are currently three classes:

RCResources
UDResources
XRXResources

The above subclasses add traffic-specific constants. For example, UDResources overrides create_mr and adds the size of the GRH header to the message size. RCResources exposes a wrapper to modify the QP to RTS.

Tests-related Classes

unittest.TestCase is a logical test unit in Python's unittest module. RDMATestCase inherits from it and adds the option to accept parameters (example will follow below) or use a random set of valid parameters:

If no device was provided, it iterates over the existing devices, for each port of each device, it checks which GID indexes are valid (in RoCE, only IPv4 and IPv6 based GIDs are used). Each <dev, port, gid> is added to an array and one entry is selected.
If a device was provided, the same process is done for all ports of this device, and so on.

Traffic Utilities

tests/utils.py offers a few wrappers for common traffic operations, making the use of default values even shorter. Those traffic utilities accept an aggregation object as their first parameter and rely on that object to have valid RDMA resources for proper functioning.

get_[send, recv]_wr() creates a [Send, Recv]WR object with a single SGE. It also sets the MR content to be ‘c’s for client side or ‘s’s for server side (this is later validated).
post_send() posts a single send request to the aggregation object's QP. If the QP is a UD QP, an address vector will be added to the send WR.
post_recv() posts the given RecvWR times, so it can be used to fill the RQ prior to traffic as well as during traffic.
poll_cq() polls completions from the CQ and raises an exception on a non-success status.
validate() verifies that the data in the MR is as expected (‘c’s for server, ‘s’s for client).
traffic() runs iterations of send/recv between 2 players.

How to run rdma-core's tests

Developers

The tests can be executed from ./build/bin:

./build.sh
./build/bin/run_tests.py

Users

The tests are not a Python package, as such they can be found under /usr/share/doc/rdma-core-{version}/tests. In order to run all tests:

python /usr/share/doc/rdma-core-<version>/tests/run_tests.py

Execution output

Output will be something like:

$ ./build/bin/run_tests.py
..........................................ss...............
----------------------------------------------------------------------
Ran 59 tests in 13.268s

OK (skipped=2)

A dot represents a passing test. ‘s’ means a skipped test. ‘E’ means a test that failed.

Tests can also be executed in verbose mode:

$ python3 /usr/share/doc/rdma-core-26.0/tests/run_tests.py -v
test_create_ah (test_addr.AHTest) ... ok
test_create_ah_roce (test_addr.AHTest) ... ok
test_destroy_ah (test_addr.AHTest) ... ok
test_create_comp_channel (test_cq.CCTest) ... ok
< many more lines here>
test_odp_rc_traffic (test_odp.OdpTestCase) ... skipped 'No port is up, can't run traffic'
test_odp_ud_traffic (test_odp.OdpTestCase) ... skipped 'No port is up, can't run traffic'
<more lines>

----------------------------------------------------------------------
Ran 59 tests in 12.857s

OK (skipped=2)

Verbose mode provides the reason for skipping the test (if one was provided by the test developer).

Customized Execution

tests/__init__.py defines a _load_tests function that returns an array with the tests that will be executed. The default implementation collects all test_* methods from all the classes that inherit from unittest.TestCase (or RDMATestCase) and located in files under tests directory which names starts with test_. Users can execute part of the tests by adding -k to the run_tests.py command. The following example executes only tests cases in files starting with test_device and not test_.

$ build/bin/run_tests.py -v -k test_device
test_create_dm (tests.test_device.DMTest) ... ok
test_create_dm_bad_flow (tests.test_device.DMTest) ... ok
test_destroy_dm (tests.test_device.DMTest) ... ok
test_destroy_dm_bad_flow (tests.test_device.DMTest) ... ok
test_dm_read (tests.test_device.DMTest) ... ok
test_dm_write (tests.test_device.DMTest) ... ok
test_dm_write_bad_flow (tests.test_device.DMTest) ... ok
test_dev_list (tests.test_device.DeviceTest) ... ok
test_open_dev (tests.test_device.DeviceTest) ... ok
test_query_device (tests.test_device.DeviceTest) ... ok
test_query_device_ex (tests.test_device.DeviceTest) ... ok
test_query_gid (tests.test_device.DeviceTest) ... ok
test_query_port (tests.test_device.DeviceTest) ... ok
test_query_port_bad_flow (tests.test_device.DeviceTest) ... ok

----------------------------------------------------------------------
Ran 14 tests in 0.152s

OK

GPUDirect RDMA

Part of the available tests includes GPUDirect RDMA. Those tests run RDMA traffic over CUDA-allocated memory. In order to run them successfully it's required to have a supported NVIDIA GPU, CUDA 11.7 and above with “Open flavor” (“-m kernel-open”) Driver 515 or later and cuda-python 12.0 and above. Running the tests is similar to other tests, with the option to choose which GPU unit to use in case there are multiple GPUs on the setup.

$ build/bin/run_tests.py -v --gpu 0 -k cuda
test_cuda_dmabuf_rdma_write_traffic (tests.test_cuda_dmabuf.DmabufCudaTest)
Runs RDMA Write traffic over CUDA allocated memory using DMA BUF and ... ok
test_mlx_devx_cuda_send_imm_traffic (tests.test_mlx5_cuda_umem.Mlx5GpuDevxRcTrafficTest)
Creates two DevX RC QPs and runs SEND_IMM traffic over CUDA allocated ... ok

----------------------------------------------------------------------
Ran 2 tests in 3.033s

OK

Writing Tests

The following section explains how to add a new test, using tests/test_odp.py as an example. It's a simple test that runs ping-pong over a few different traffic types.

ODP requires capability check, so a decorator was added to tests/utils.py. The first change for ODP execution is when registering a memory region (need to set the ON_DEMAND access flag), so we do as follows:

Create the players by inheriting from RCResources (for RC traffic).
In the player, override create_mr() and add the decorator to it. It will run before the actual call to ibv_reg_mr and if ODP caps are off, the test will be skipped.
Create the OdpTestCase by inheriting from RDMATestCase.
In the test case, add a method starting with test_, to let the unittest infrastructure that this is a test.
In the test method, create the players (which already check the ODP caps) and call the traffic() function, providing it the two players.