net/mlx5e: Support enhanced CQE compression

CQE compression feature improves performance by reducing PCI bandwidth
bottleneck on CQEs write.
Enhanced CQE compression introduced in ConnectX-6 and it aims to reduce
CPU utilization of SW side packets decompression by eliminating the
need to rewrite ownership bit, which is likely to cost a cache-miss, is
replaced by validity byte handled solely by HW.
Another advantage of the enhanced feature is that session packets are
available to SW as soon as a single CQE slot is filled, instead of
waiting for session to close, this improves packet latency from NIC to
host.

Performance:
Following are tested scenarios and reults comparing basic and enahnced
CQE compression.

setup: IXIA 100GbE connected directly to port 0 and port 1 of
ConnectX-6 Dx 100GbE dual port.

Case #1 RX only, single flow goes to single queue:
IRQ rate reduced by ~ 30%, CPU utilization improved by 2%.

Case #2 IP forwarding from port 1 to port 0 single flow goes to
single queue:
Avg latency improved from 60us to 21us, frame loss improved from 0.5% to 0.0%.

Case #3 IP forwarding from port 1 to port 0 Max Throughput IXIA sends
100%, 8192 UDP flows, goes to 24 queues:
Enhanced is equal or slightly better than basic.

Testing the basic compression feature with this patch shows there is
no perfrormance degradation of the basic compression feature.

Signed-off-by: Ofer Levi <oferle@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/mlx5/device.h b/include/linux/mlx5/device.h
index 1ff91cb79ded..eb3fac30488b 100644
--- a/include/linux/mlx5/device.h
+++ b/include/linux/mlx5/device.h
@@ -882,6 +882,12 @@ static inline u8 get_cqe_opcode(struct mlx5_cqe64 *cqe)
 	return cqe->op_own >> 4;
 }
 
+static inline u8 get_cqe_enhanced_num_mini_cqes(struct mlx5_cqe64 *cqe)
+{
+	/* num_of_mini_cqes is zero based */
+	return get_cqe_opcode(cqe) + 1;
+}
+
 static inline u8 get_cqe_lro_tcppsh(struct mlx5_cqe64 *cqe)
 {
 	return (cqe->lro.tcppsh_abort_dupack >> 6) & 1;