net/mlx5: reduce memory overhead for BF handling

Blue Flame (aka BF) is a buffer allocated with a power of two value, its
size is returned by Verbs in log2.

Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>

diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index e3b03b3..897c23b 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -413,7 +413,7 @@ mlx5_tx_dbrec(struct txq *txq)
        /* Ensure ordering between DB record and BF copy. */
        rte_wmb();
        rte_mov16(dst, (uint8_t *)data);
-       txq->bf_offset ^= txq->bf_buf_size;
+       txq->bf_offset ^= (1 << txq->bf_buf_size);
 }
 
 /**

diff --git a/drivers/net/mlx5/mlx5_rxtx.h b/drivers/net/mlx5/mlx5_rxtx.h
index 78a1f8a..61c9233 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxtx.h
+++ b/drivers/net/mlx5/mlx5_rxtx.h
@@ -249,8 +249,8 @@ struct txq {
        uint16_t wqe_n; /* Number of WQ elements. */
        uint16_t elts_n:4; /* (*elts)[] length (in log2). */
        uint16_t cqe_n:4; /* Number of CQ elements (in log2). */
+       uint16_t bf_buf_size:4; /* Log2 Blueflame size. */
        uint16_t bf_offset; /* Blueflame offset. */
-       uint16_t bf_buf_size; /* Blueflame size. */
        uint16_t max_inline; /* Multiple of RTE_CACHE_LINE_SIZE to inline. */
        uint32_t qp_num_8s; /* QP number shifted by 8. */
        volatile struct mlx5_cqe (*cqes)[]; /* Completion queue. */

diff --git a/drivers/net/mlx5/mlx5_txq.c b/drivers/net/mlx5/mlx5_txq.c
index 3fc9e55..94ed3fc 100644 (file)
--- a/drivers/net/mlx5/mlx5_txq.c
+++ b/drivers/net/mlx5/mlx5_txq.c
@@ -221,7 +221,7 @@ txq_setup(struct txq_ctrl *tmpl, struct txq_ctrl *txq_ctrl)
        tmpl->txq.qp_db = &qp->gen_data.db[MLX5_SND_DBR];
        tmpl->txq.bf_reg = qp->gen_data.bf->reg;
        tmpl->txq.bf_offset = qp->gen_data.bf->offset;
-       tmpl->txq.bf_buf_size = qp->gen_data.bf->buf_size;
+       tmpl->txq.bf_buf_size = log2above(qp->gen_data.bf->buf_size);
        tmpl->txq.cq_db = cq->dbrec;
        tmpl->txq.cqes =
                (volatile struct mlx5_cqe (*)[])