Re: dpdk-testpmd fails with a Mellanox ConnectX-4 Lx NIC

["Gábor LENCSE" <lencse@hit.bme.hu>]

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Hi Dmitry,

2025. 02. 24. 21:37 keltezéssel, Dmitry Kozlyuk írta:
> Mellanox NICs need mlx5_core kernel driver even when used via DPDK.

Indeed, it works! Thank you very much! I would have never thought of that.

However, it seems to be rather slow and it loses frames.

With my siitperf ( https://github.com/lencsegabor/siitperf ) measurement 
program I can achieve 7.1Mfps per direction using bidirectional traffic 
with 64-byte frame size when I use X540. And the bottleneck is surely 
the X540, as the numbers are the same when I use fixed IP addresses and 
port numbers and when any or both of them varies. With X710, I can 
achieve more that 8Mfps using RFC 4814 pseudorandom port numbers and 
more than 10Mfps using fixed frames (using bidirectional traffic with 
64-byte frame size).

However the first step of the binary search of the throughput test using 
8Mfps rate lasted more than 120s (instead of 60s).

What is worse, the binary search counts down to 0 due to the loss of a 
small amount of packets.

Here is the current output:

--------------------------------------------------- 2025-02-24 
22:26:18.165766809 Iteration no. 1-8 
--------------------------------------------------- Testing rate: 31250 
fps. EAL: Detected 16 lcore(s) EAL: Detected 2 NUMA nodes EAL: Detected 
shared linkage of DPDK EAL: Multi-process socket 
/var/run/dpdk/rte/mp_socket EAL: Selected IOVA mode 'VA' EAL: Probing 
VFIO support... EAL: VFIO support initialized EAL: Probe PCI driver: 
mlx5_pci (15b3:1015) device: 0000:05:00.0 (socket 0) EAL: Probe PCI 
driver: mlx5_pci (15b3:1015) device: 0000:05:00.1 (socket 0) EAL: Probe 
PCI driver: net_mlx4 (15b3:1007) device: 0000:82:00.0 (socket 1) EAL: No 
legacy callbacks, legacy socket not created Info: Left port and Left 
Sender CPU core belong to the same NUMA node: 0 Info: Right port and 
Right Receiver CPU core belong to the same NUMA node: 0 Info: Right port 
and Right Sender CPU core belong to the same NUMA node: 0 Info: Left 
port and Left Receiver CPU core belong to the same NUMA node: 0 Info: 
Testing initiated at 2025-02-24 22:26:19 Info: Forward sender's sending 
took 59.9999682437 seconds. Forward frames sent: 1875000 Info: Reverse 
sender's sending took 59.9999682300 seconds. Reverse frames sent: 
1875000 Reverse frames received: 1874963 Forward frames received: 
1874958 Info: Test finished. Forward: 1874958 frames were received from 
the required 1875000 frames Reverse: 1874963 frames were received from 
the required 1875000 frames TEST FAILED

Do you have any idea, what is happening here?

Best regards,

Gábor

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