[dpdk-dev] Intel XL710 with KVM-SRIOV & DPDK i40evf driver drops packets on RX even on a small rates

[Vishnuvardhan Reddy]

Hi,

We are running performance characterization for our customized DPDK
application in the KVM Guest using Intel XL710 SRIOV VF.
The Host is Netra X72 with XL710 NIC Quad port with 32 core.
We are seeing RX packet drops at the VF level even for small packet rates
(~200Mbps) & the DPDK rx_discard counter of i40evf is getting
incremented.
When we go through the XL710 data sheet, we got the following description
for rx_discards.

*Port Receive Packets Discarded Count GLPRT_RDPC[n] (0x00300600 + 0x8*n,
n=0...3; RW1C)*

*    Counts received packets from the network that are dropped in the
receive packet buffer. The packets are dropped due to possible lack of
bandwidth on the PCIe or total bandwidth of the internal data path.*


Could you please help us how we can proceed to identify the root cause of
RX discards?


Thanks,
Vishnu