DPDK Ring Q

Lombardo, Ed Ed.Lombardo at netscout.com
Thu May 29 07:20:25 CEST 2025


Hi,
I have an issue with DPDK 24.11.1 and 2 port 100G Intel NIC (E810-C) on 22 core CPU dual socket server.

There is a dedicated CPU core to get the packets from DPDK using rte_eth_rx_burst() and enqueue the mbufs into a worker ring Q.  This thread does nothing else.  The NIC is dropping packets at 8.5 Gbps per port.

Studying the perf report, I was interested in the common_ring_mc_dequeue().  Perf tool shows common_ring_mc_dequeue() 92.86% Self and 92.86% Children.

I see further with perf tool rte_ring_enqueue_bulk() and rte_ring_enqueue_bulk_elem().  These are at 0.00% Self and 0.05% Children.
Perf tool shows rte_ring_sp_enqueue_bulk_elem (inlined) which is what I wanted to see (Single producer) representing the enqueue of the mbufs pointers to the worker ring Q.

Is it possible to change the common_ring_mc_dequeue() to common_ring_sc_dequeue()?  Can it be set to one consumer on single Queue 0.

I believe this is limiting DPDK from reaching 90 Gbps or higher in my setup, which is my goal.

I made sure the E810-C firmware was up to date, NIC FW Version: 4.80 0x80020543 1.3805.0

Perf report shows:
   - 99.65% input_thread
      - 99.35% rte_eth_rx_burst (inlined)
         - ice_recv_scattered_pkts
              92.83% common_ring_mc_dequeue

Any thoughts or suggestions?

Thanks,
Ed
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