From e10245a13b2e340f48ce80484f19bcbc13e9ebe6 Mon Sep 17 00:00:00 2001 From: Yongseok Koh Date: Tue, 26 Jun 2018 04:33:35 -0700 Subject: [PATCH 1/1] net/mlx5: fix Rx buffer replenishment threshold The threshold of buffer replenishment for vectorized Rx burst is a constant value (64). If the size of Rx queue is comparatively small, device could run out of buffers. For example, if the size of Rx queue is 128, buffers are replenished only twice per a wraparound. This can cause jitter in receiving packets and the jitter can cause unnecessary retransmission for TCP connections. Fixes: 6cb559d67b83 ("net/mlx5: add vectorized Rx/Tx burst for x86") Fixes: 570acdb1da8a ("net/mlx5: add vectorized Rx/Tx burst for ARM") Cc: stable@dpdk.org Signed-off-by: Yongseok Koh Acked-by: Shahaf Shuler --- drivers/net/mlx5/mlx5_defs.h | 5 +++-- drivers/net/mlx5/mlx5_rxtx_vec.h | 4 ++-- drivers/net/mlx5/mlx5_rxtx_vec_neon.h | 2 +- drivers/net/mlx5/mlx5_rxtx_vec_sse.h | 2 +- 4 files changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/net/mlx5/mlx5_defs.h b/drivers/net/mlx5/mlx5_defs.h index 51124cdcc5..b52f7dcbe6 100644 --- a/drivers/net/mlx5/mlx5_defs.h +++ b/drivers/net/mlx5/mlx5_defs.h @@ -64,10 +64,11 @@ #define MLX5_VPMD_MIN_TXQS 4 /* Threshold of buffer replenishment for vectorized Rx. */ -#define MLX5_VPMD_RXQ_RPLNSH_THRESH 64U +#define MLX5_VPMD_RXQ_RPLNSH_THRESH(n) \ + (RTE_MIN(MLX5_VPMD_RX_MAX_BURST, (unsigned int)(n) >> 2)) /* Maximum size of burst for vectorized Rx. */ -#define MLX5_VPMD_RX_MAX_BURST MLX5_VPMD_RXQ_RPLNSH_THRESH +#define MLX5_VPMD_RX_MAX_BURST 64U /* * Maximum size of burst for vectorized Tx. This is related to the maximum size diff --git a/drivers/net/mlx5/mlx5_rxtx_vec.h b/drivers/net/mlx5/mlx5_rxtx_vec.h index 598dc7519b..fb884f92fd 100644 --- a/drivers/net/mlx5/mlx5_rxtx_vec.h +++ b/drivers/net/mlx5/mlx5_rxtx_vec.h @@ -91,9 +91,9 @@ mlx5_rx_replenish_bulk_mbuf(struct mlx5_rxq_data *rxq, uint16_t n) &((volatile struct mlx5_wqe_data_seg *)rxq->wqes)[elts_idx]; unsigned int i; - assert(n >= MLX5_VPMD_RXQ_RPLNSH_THRESH); + assert(n >= MLX5_VPMD_RXQ_RPLNSH_THRESH(q_n)); assert(n <= (uint16_t)(q_n - (rxq->rq_ci - rxq->rq_pi))); - assert(MLX5_VPMD_RXQ_RPLNSH_THRESH > MLX5_VPMD_DESCS_PER_LOOP); + assert(MLX5_VPMD_RXQ_RPLNSH_THRESH(q_n) > MLX5_VPMD_DESCS_PER_LOOP); /* Not to cross queue end. */ n = RTE_MIN(n - MLX5_VPMD_DESCS_PER_LOOP, q_n - elts_idx); if (rte_mempool_get_bulk(rxq->mp, (void *)elts, n) < 0) { diff --git a/drivers/net/mlx5/mlx5_rxtx_vec_neon.h b/drivers/net/mlx5/mlx5_rxtx_vec_neon.h index 71a5eaf23e..3ebf34823e 100644 --- a/drivers/net/mlx5/mlx5_rxtx_vec_neon.h +++ b/drivers/net/mlx5/mlx5_rxtx_vec_neon.h @@ -739,7 +739,7 @@ rxq_burst_v(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts, uint16_t pkts_n, * N - (rq_ci - rq_pi) := # of buffers consumed (to be replenished). */ repl_n = q_n - (rxq->rq_ci - rxq->rq_pi); - if (repl_n >= MLX5_VPMD_RXQ_RPLNSH_THRESH) + if (repl_n >= MLX5_VPMD_RXQ_RPLNSH_THRESH(q_n)) mlx5_rx_replenish_bulk_mbuf(rxq, repl_n); /* See if there're unreturned mbufs from compressed CQE. */ rcvd_pkt = rxq->cq_ci - rxq->rq_pi; diff --git a/drivers/net/mlx5/mlx5_rxtx_vec_sse.h b/drivers/net/mlx5/mlx5_rxtx_vec_sse.h index 3e985d61d5..f0d8888310 100644 --- a/drivers/net/mlx5/mlx5_rxtx_vec_sse.h +++ b/drivers/net/mlx5/mlx5_rxtx_vec_sse.h @@ -724,7 +724,7 @@ rxq_burst_v(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts, uint16_t pkts_n, * N - (rq_ci - rq_pi) := # of buffers consumed (to be replenished). */ repl_n = q_n - (rxq->rq_ci - rxq->rq_pi); - if (repl_n >= MLX5_VPMD_RXQ_RPLNSH_THRESH) + if (repl_n >= MLX5_VPMD_RXQ_RPLNSH_THRESH(q_n)) mlx5_rx_replenish_bulk_mbuf(rxq, repl_n); /* See if there're unreturned mbufs from compressed CQE. */ rcvd_pkt = rxq->cq_ci - rxq->rq_pi; -- 2.20.1