[PATCH net-next 11/13] net/mlx5e: Prefetch next RX CQE

[Saeed Mahameed]

From: Tariq Toukan <tar...@mellanox.com>

Performance optimization that prefetches the next RX CQE while
handling the current one.

Performance tested on ConnectX4-Lx 50G.
* Netperf single TCP stream:
- bw raise of 3-10% for various representative messages sizes.

Signed-off-by: Tariq Toukan <tar...@mellanox.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c 
b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index aa7f90c..b53e9bd 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -664,15 +664,19 @@ mpwrq_cqe_out:
 int mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget)
 {
        struct mlx5e_rq *rq = container_of(cq, struct mlx5e_rq, cq);
+       struct mlx5_cqe64 *next_cqe = mlx5e_get_cqe(cq);
+       struct mlx5_cqe64 *cqe;
        int work_done;
 
        for (work_done = 0; work_done < budget; work_done++) {
-               struct mlx5_cqe64 *cqe = mlx5e_get_cqe(cq);
+               cqe = next_cqe;
 
                if (!cqe)
                        break;
 
                mlx5_cqwq_pop(&cq->wq);
+               next_cqe = mlx5e_get_cqe(cq);
+               prefetch(next_cqe);
 
                rq->handle_rx_cqe(rq, cqe);
        }
-- 
1.7.1