On Mon, 28 Apr 2025 11:31:10 +0530 Prashant Upadhyaya <praupadhy...@gmail.com> wrote:
> On Sat, 26 Apr 2025 at 20:58, Stephen Hemminger <step...@networkplumber.org> > wrote: > > > On Fri, 25 Apr 2025 23:17:30 +0530 > > Prashant Upadhyaya <praupadhy...@gmail.com> wrote: > > > > > Hi, > > > > > > I am having a VM on Azure where I have got two 'accelerated networking' > > > interfaces of Mellanox > > > # lspci -nn|grep -i ether > > > 6561:00:02.0 Ethernet controller [0200]: Mellanox Technologies MT27710 > > > Family [ConnectX-4 Lx Virtual Function] [15b3:1016] (rev 80) > > > f08c:00:02.0 Ethernet controller [0200]: Mellanox Technologies MT27710 > > > Family [ConnectX-4 Lx Virtual Function] [15b3:1016] (rev 80) > > > > > > I have a DPDK application which needs to obtain 'all' packets from the > > NIC. > > > I installed the drivers, compiled DPDK24.11 (Ubuntu20.04), my app starts > > > and is able to detect the NIC's. > > > Everything looks good > > > myapp.out -c 0x07 -a f08c:00:02.0 -a 6561:00:02.0 > > > EAL: Detected CPU lcores: 8 > > > EAL: Detected NUMA nodes: 1 > > > EAL: Detected shared linkage of DPDK > > > EAL: Multi-process socket /var/run/dpdk/rte/mp_socket > > > EAL: Selected IOVA mode 'PA' > > > EAL: VFIO support initialized > > > mlx5_net: Default miss action is not supported. > > > mlx5_net: Default miss action is not supported. > > > All Ports initialized > > > Port 0 is UP (50000 Mbps) > > > Port 1 is UP (50000 Mbps) > > > > > > The trouble is that the ARP packets are not being picked up by my DPDK > > > application, I see them being delivered to the kernel via the eth > > interface > > > corresponding to the port (MLX is a bifurcated driver, you don't really > > > bind to the NIC, so you still see the eth interfaces at linux level and > > can > > > run tcpdump on those, I see ARP packets in the tcpdump there on the > > > interface) > > > I can receive UDP packets in my DPDK app though. > > > > > > My application is not setting any rte_flow rules etc. so I was expecting > > > that by default my dpdk app would get all the packets as is normally the > > > case with other NIC's > > > Is there something I need to configure for Mellanox NIC somewhere such > > that > > > I get 'all' the packets including ARP packets in my DPDK app ? > > > > > > Regards > > > -Prashant > > > > The Mellanox device in Azure networking cards is only used as a VF switch. > > You can go back to earlier DPDK presentations for more detail. > > > > Three reason bifurcation won't work. > > 1. Only some of the packets arrive on the VF. All non-IP show up on > > the synthetic device. The VF is only used after the TCP three way > > handshake. > > 2. The Netvsc PMD doesn't handle flow rules. > > 3. The VF can be removed and restored any time (by hypervisor) > > it is not a stable entity. > > > > > Thanks Stephen, so are we concluding that DPDK apps are unusable in Azure > as per my requirements, is there no work around or any other possibility to > use DPDK in Azure VM ? Please do send me a link to the correct presentation > I should refer to. > > Regards > -Prashant Remember in the cloud network interfaces are free, there really is no need for bifurication just create two interfaces to VM, one for DPDK, and one for non DPDK.
