Enabling RDMA
Learn more about RDMA in the technology overview section.
There are two parts to enabling RDMA for Holoscan:
Skip to the next section if you do not plan to leverage a ConnectX SmartNIC.
The NVIDIA IGX Orin developer kit comes with an embedded ConnectX Ethernet adapter to offer advanced hardware offloads and accelerations. You can also purchase an individual ConnectX adapter and install it on other systems such as x86_64 workstations.
The following steps are required to ensure your ConnectX can be used for RDMA over Converged Ethernet (RoCE):
1. Install MOFED drivers
Ensure the Mellanox OFED drivers version 23.10 or above are installed:
cat /sys/module/mlx5_core/version
If not installed, or an older version, install the appropriate version from the MLNX_OFED download page, or use the script below:
# You can choose different versions/OS or download directly from the
# Download Center in the webpage linked above
MOFED_VERSION="23.10-2.1.3.1"
OS="ubuntu22.04"
MOFED_PACKAGE="MLNX_OFED_LINUX-${MOFED_VERSION}-${OS}-$(uname -m)"
wget --progress=dot:giga https://www.mellanox.com/downloads/ofed/MLNX_OFED-${MOFED_VERSION}/${MOFED_PACKAGE}.tgz
tar xf ${MOFED_PACKAGE}.tgz
sudo ./${MOFED_PACKAGE}/mlnxofedinstall
# add the --force flag to force uninstallation if necessary:
# sudo ./${MOFED_PACKAGE}/mlnxofedinstall --force
rm -r ${MOFED_PACKAGE}*
2. Load MOFED drivers
Ensure the drivers are loaded:
sudo lsmod | grep ib_core
If nothing appears, run the following command:
sudo /etc/init.d/openibd restart
3. Switch the board Link Layer to Ethernet
The ConnectX SmartNIC can function in two separate modes (called link layer):
Ethernet (ETH)
Infiniband (IB)
Holoscan does not support IB at this time (not tested), so the ConnectX will need to use the ETH link layer.
To identify the current mode, run ibstat or ibv_devinfo and look for the Link Layer value. In the example below, the mlx5_0 interface is in Ethernet mode, while the mlx5_1 interface is in Infiniband mode. Do not pay attention to the transport value which is always InfiniBand.
$ ibstat
CA 'mlx5_0'
CA type: MT4129
Number of ports: 1
Firmware version: 28.37.0190
Hardware version: 0
Node GUID: 0x48b02d0300ee7a04
System image GUID: 0x48b02d0300ee7a04
Port 1:
State: Down
Physical state: Disabled
Rate: 40
Base lid: 0
LMC: 0
SM lid: 0
Capability mask: 0x00010000
Port GUID: 0x4ab02dfffeee7a04
Link layer: Ethernet
CA 'mlx5_1'
CA type: MT4129
Number of ports: 1
Firmware version: 28.37.0190
Hardware version: 0
Node GUID: 0x48b02d0300ee7a05
System image GUID: 0x48b02d0300ee7a04
Port 1:
State: Active
Physical state: LinkUp
Rate: 100
Base lid: 0
LMC: 0
SM lid: 0
Capability mask: 0x00010000
Port GUID: 0x4ab02dfffeee7a05
Link layer: InfiniBand
If no results appear after ibstat and sudo lsmod | grep ib_core returns a result like this:
ib_core 425984 1 ib_uverbs
Consider running the following command or rebooting:
sudo /etc/init.d/openibd restart
To switch the link layer mode, there are two possible options:
On IGX Orin developer kits, you can switch that setting through the BIOS: see IGX Orin documentation.
On any system with a ConnectX (including IGX Orin devkits), you can run the command below from a terminal (requires a reboot).
sudo ibdev2netdev -vis used to identify the PCI address of the ConnectX (any of the two interfaces is fine to use), andmlxconfigis used to apply the changes.mlx_pci=$(sudo ibdev2netdev -v | awk '{print $1}' | head -n1) sudo mlxconfig -d $mlx_pci set LINK_TYPE_P1=ETH LINK_TYPE_P2=ETH
Note:
LINK_TYPE_P1andLINK_TYPE_P2are formlx5_0andmlx5_1respectively. You can choose to only set one of them. You can passETHor2for Ethernet mode, andIBor1for InfiniBand.This is the output of the command above:
Device #1: ---------- Device type: ConnectX7 Name: P3740-B0-QSFP_Ax Description: NVIDIA Prometheus P3740 ConnectX-7 VPI PCIe Switch Motherboard; 400Gb/s; dual-port QSFP; PCIe switch5.0 X8 SLOT0 ;X16 SLOT2; secure boot; Device: 0005:03:00.0 Configurations: Next Boot New LINK_TYPE_P1 ETH(2) ETH(2) LINK_TYPE_P2 IB(1) ETH(2) Apply new Configuration? (y/n) [n] :
Next Bootis actually the current value that was expected to be used at the next reboot, whileNewis the value you’re about to set to overrideNext Boot.Apply with
yand reboot afterwards:Applying... Done! -I- Please reboot machine to load new configurations.
4. Configure the IP addresses of the ethernet interfaces
First, identify the logical names of your ConnectX interfaces. Connecting a cable in just one of the interfaces on the ConnectX will help you identify which port is which (in the example below, only mlx5_1 i.e. eth3 is connected):
$ sudo ibdev2netdev
mlx5_0 port 1 ==> eth2 (Down)
mlx5_1 port 1 ==> eth3 (Up)
For IGX Orin Developer Kits with no live source to connect to the ConnectX QSFP ports, adding -v can show you which logical name is mapped to each specific port:
0005:03.00.0is the QSFP port closer to the PCI slots0005:03.00.1is the QSFP closer to the RJ45 ethernet ports
$ sudo ibdev2netdev -v
0005:03:00.0 mlx5_0 (MT4129 - P3740-0002 ) NVIDIA IGX, P3740-0002, 2-port QSFP up to 400G, InfiniBand and Ethernet, PCIe5 fw 28.37.0190 port 1 (DOWN ) ==> eth2 (Down)
0005:03:00.1 mlx5_1 (MT4129 - P3740-0002 ) NVIDIA IGX, P3740-0002, 2-port QSFP up to 400G, InfiniBand and Ethernet, PCIe5 fw 28.37.0190 port 1 (DOWN ) ==> eth2 (Down)
If you have a cable connected but it does not show Up/Down in the output of ibdev2netdev, you can try to parse the output of dmesg instead. The example below shows that 0005:03:00.1 is plugged, and that it is associated with eth3:
$ sudo dmesg | grep -w mlx5_core
...
[ 11.512808] mlx5_core 0005:03:00.0 eth2: Link down
[ 11.640670] mlx5_core 0005:03:00.1 eth3: Link down
...
[ 3712.267103] mlx5_core 0005:03:00.1: Port module event: module 1, Cable plugged
The next step is to set a static IP on the interface you’d like to use so you can refer to it in your Holoscan applications (ex: Emergent cameras, distributed applications…).
First, check if you already have an address setup. We’ll use the eth3 interface in this example for mlx5_1:
ip -f inet addr show eth3
If nothing appears or you’d like to change the address, you can set an IP and MTU (Maximum Transmission Unit) through the Network Manager user interface, CLI (nmcli), or other IP configuration tools. In the example below, we use ip (ifconfig is legacy) to configure the eth3 interface with an address of 192.168.1.1/24 and a MTU of 9000 (i.e. “jumbo frame”) to send Ethernet frames with a payload greater than the standard size of 1500 bytes:
sudo ip link set dev eth3 down
sudo ip addr add 192.168.1.1/24 dev eth3
sudo ip link set dev eth3 mtu 9000
sudo ip link set dev eth3 up
If you are connecting the ConnectX to another ConnectX with a LinkX interconnect, do the same on the other system with an IP address on the same network segment.
For example, to communicate with 192.168.1.1/24 above (/24 -> 255.255.255.0 submask), setup your other system with an IP between 192.168.1.2 and 192.168.1.254, and the same /24 submask.
Only supported on NVIDIA’s Quadro/workstation GPUs (not GeForce).
Follow the instructions below to enable GPUDirect RDMA:
On dGPU, the GPUDirect RDMA drivers are named nvidia-peermem, and are installed with the rest of the NVIDIA dGPU drivers.
To enable the use of GPUDirect RDMA with a ConnectX SmartNIC (section above), the following steps are required if the MOFED drivers were installed after the peermem drivers:
nv_driver_version=$(modinfo nvidia | awk '/^version:/ {print $2}' | cut -d. -f1)
sudo dpkg-reconfigure nvidia-dkms-$nv_driver_version # or nvidia-dkms-${nv_driver_version}-server
Load the peermem kernel module manually:
sudo modprobe nvidia-peermem
Run the following to load it automatically during boot:
echo nvidia-peermem | sudo tee -a /etc/modules
At this time the IGX SW 1.0 DP and JetPack 6.0 DP are missing the nvidia-p2p kernel for support for GPU Direct RDMA support. They’re planned in the respective GA releases. The instructions below are to load the kernel module once it is packaged in the GA releases.
On iGPU, the GPUDirect RDMA drivers are named nvidia-p2p. Run the following to load the kernel module manually:
sudo modprobe nvidia-p2p
Run the following to load it automatically during boot:
echo nvidia-p2p | sudo tee -a /etc/modules
The instructions below describe the steps to test GPUDirect using the
Rivermax SDK. The test applications used by
these instructions, generic_sender and generic_receiver, can
then be used as samples in order to develop custom applications that use the
Rivermax SDK to optimize data transfers.
The Linux default path where Rivermax expects to find the license file is /opt/mellanox/rivermax/rivermax.lic, or you can specify the full path and file name for the environment variable RIVERMAX_LICENSE_PATH.
If manually installing the Rivermax SDK from the link above, please note there is no need to follow the steps for installing MLNX_OFED/MLNX_EN in the Rivermax documentation.
Running the Rivermax sample applications requires two systems, a sender and a receiver, connected via ConnectX network adapters. If two Developer Kits are used then the onboard ConnectX can be used on each system, but if only one Developer Kit is available then it is expected that another system with an add-in ConnectX network adapter will need to be used. Rivermax supports a wide array of platforms, including both Linux and Windows, but these instructions assume that another Linux based platform will be used as the sender device while the Developer Kit is used as the receiver.
The $rivermax_sdk variable referenced below corresponds to the path where the Rivermax SDK
package was installed. If the Rivermax SDK was installed via SDK Manager, this path will be:
rivermax_sdk=$HOME/Documents/Rivermax/1.31.10
If the Rivermax SDK was installed via a manual download, make sure to export your path to the SDK:
rivermax_sdk=$DOWNLOAD_PATH/1.31.10
Install path might differ in future versions of Rivermax.
Determine the logical name for the ConnectX devices that are used by each system. This can be done by using the
lshw -class networkcommand, finding theproduct:entry for the ConnectX device, and making note of thelogical name:that corresponds to that device. For example, this output on a Developer Kit shows the onboard ConnectX device using theenp9s0f01logical name (lshwoutput shortened for demonstration purposes).$ sudo lshw -class network *-network:0 description: Ethernet interface product: MT28908 Family [ConnectX-6] vendor: Mellanox Technologies physical id: 0 bus info: pci@0000:09:00.0 <b>logical name: enp9s0f0</b> version: 00 serial: 48:b0:2d:13:9b:6b capacity: 10Gbit/s width: 64 bits clock: 33MHz capabilities: pciexpress vpd msix pm bus_master cap_list ethernet physical 1000bt-fd 10000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=mlx5_core driverversion=5.4-1.0.3 duplex=full firmware=20.27.4006 (NVD0000000001) ip=10.0.0.2 latency=0 link=yes multicast=yes resources: iomemory:180-17f irq:33 memory:1818000000-1819ffffff
The instructions that follow will use the
enp9s0f0logical name forifconfigcommands, but these names should be replaced with the corresponding logical names as determined by this step.Run the
generic_senderapplication on the sending system.a. Bring up the network:
$ sudo ifconfig enp9s0f0 up 10.0.0.1
b. Build the sample apps:
$ cd ${rivermax_sdk}/apps $ make
e. Launch the
generic_senderapplication:$ sudo ./generic_sender -l 10.0.0.1 -d 10.0.0.2 -p 5001 -y 1462 -k 8192 -z 500 -v
which gives
+############################################# | Sender index: 0 | Thread ID: 0x7fa1ffb1c0 | CPU core affinity: -1 | Number of streams in this thread: 1 | Memory address: 0x7f986e3010 | Memory length: 59883520[B] | Memory key: 40308 +############################################# | Stream index: 0 | Source IP: 10.0.0.1 | Destination IP: 10.0.0.2 | Destination port: 5001 | Number of flows: 1 | Rate limit bps: 0 | Rate limit max burst in packets: 0 | Memory address: 0x7f986e3010 | Memory length: 59883520[B] | Memory key: 40308 | Number of user requested chunks: 1 | Number of application chunks: 5 | Number of packets in chunk: 8192 | Packet's payload size: 1462 +**********************************************
Run the
generic_receiverapplication on the receiving system.a. Bring up the network:
$ sudo ifconfig enp9s0f0 up 10.0.0.2
b. Build the
generic_receiverapp with GPUDirect support from the Rivermax GitHub Repo. Before following the instructions to build with CUDA-Toolkit support, apply the changes to filegeneric_receiver/generic_receiver.cppin this PR, this was tested on the IGX Orin Developer Kit with Rivermax 1.31.10.c. Launch the
generic_receiverapplication from thebuilddirectory:$ sudo ./generic_receiver -i 10.0.0.2 -m 10.0.0.2 -s 10.0.0.1 -p 5001 -g 0 ... Attached flow 1 to stream. Running main receive loop... Got 5877704 GPU packets | 68.75 Gbps during 1.00 sec Got 5878240 GPU packets | 68.75 Gbps during 1.00 sec Got 5878240 GPU packets | 68.75 Gbps during 1.00 sec Got 5877704 GPU packets | 68.75 Gbps during 1.00 sec Got 5878240 GPU packets | 68.75 Gbps during 1.00 sec ...
With both the generic_sender and generic_receiver processes
active, the receiver will continue to print out received packet statistics
every second. Both processes can then be terminated with <ctrl-c>.