Hi Stephen,

Have tx queue len was 1024, increasing it to 2048 hasn't changed the behaviour. IXIA is the receiver in this case, which is definitely(and tested) capable of receiving more rate than this.

IXIA-TX --->RX(ixgbe-port0)HOST(ixgbe-port1)TX ---> IXIA-RX

Captured the rx packets count at ixgbe-port0 and tx packets count at ixgbe-port1. These 2 counters are equal and are also equal to the frames transmitted by IXIA.

But the IXIA-RX packets count reports a few hundreds-to-few thousands of packets lost on every run.

Thanks & Regards,

Rajasekhar

On Fri, Feb 17, 2023 at 9:56 PM Stephen Hemminger <stephen@networkplumber.org> wrote:

On Fri, 17 Feb 2023 11:30:14 +0530
Rajasekhar Pulluru <pullururajasekhar@gmail.com> wrote:

> Ok Stephen, thanks for the information, I can try that.
>
> One of the problems I see with single Tx Queue mode is that Ixia reports
> packet drops, though I confirmed with the help of counters (before invoking
> tx burst) that all packets are being sent-out. Dumping HW counters don't
> report any drops in TX.
> Is there a mechanism in DPDK to debug this?
>
> Thanks & Regards,
> Rajasekhar

The common usage in DPDK is to have one transmit queue per DPDK thread doing
transmits. If the transmit queue is not configured with enough depth.

The most common packet flow in DPDK is packets getting received, modified
then transmitted. With that pattern, packet loss is at the receiver when
the CPU can't keep up with the packet rate arriving.