[dpdk-users] Query on IXGBE vPMD barrier after descriptors load

[Ruifeng Wang (Arm Technology China)]

Hi Bruce,

When reading IXGBE vPMD code, I have doubt on the barrier used.  Hope you can provide more info on this.

In function _recv_raw_pkts_vec, there is a compiler_barrier after load of descs[0]:
 https://code.dpdk.org/dpdk/latest/source/drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c#L469<https://code.dpdk.org/dpdk/latest/source/drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c>

Could you give some hint about what sequence it is ensuring?
Similar barrier for NEON vPMD on aarch64 platform impacts performance much.

Regards,
/Ruifeng