net/mlx5e: RX, Use cyclic WQ in legacy RQ
Now that LRO is not supported for Legacy RQ, there is no source of out-of-order completions in the WQ, and we can use a cyclic one. This has multiple advantages: - reduces the WQE size (smaller PCI transactions). - lower overhead in datapath (no handling of 'next' pointers). - no reserved WQE for the WQ head (was need in linked-list). - allows using a constant map between frag and dma_info struct, in downstream patch. Performance tests: ConnectX-4, single core, single RX ring. Major gain in packet rate of single ring XDP drop. Bottleneck is shifted form HW (at 16Mpps) to SW (at 20Mpps). Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Showing
Please register or sign in to comment