Micro-optimize mlx4_poll_one()

Rather than byte-swapping cqe->g_mlpath_rqpn each time we extract a
field from it, byte-swap it once into a temporary variable.  This
results in smaller, better code.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --git a/src/cq.c b/src/cq.c
index bc53f9bd5ecf9c88c7810b2f99267bafec90db0f..06ae9e2bd6086ed7e9505a1df0c1ebcee862cc79 100644 (file)
--- a/src/cq.c
+++ b/src/cq.c
@@ -196,6 +196,7 @@ static int mlx4_poll_one(struct mlx4_cq *cq,
        struct mlx4_cqe *cqe;
        struct mlx4_srq *srq;
        uint32_t qpn;
+       uint32_t g_mlpath_rqpn;
        uint16_t wqe_index;
        int is_error;
        int is_send;
@@ -314,11 +315,11 @@ static int mlx4_poll_one(struct mlx4_cq *cq,
 
                wc->slid           = ntohs(cqe->rlid);
                wc->sl             = cqe->sl >> 4;
-               wc->src_qp         = ntohl(cqe->g_mlpath_rqpn) & 0xffffff;
-               wc->dlid_path_bits = (ntohl(cqe->g_mlpath_rqpn) >> 24) & 0x7f;
+               g_mlpath_rqpn      = ntohl(cqe->g_mlpath_rqpn);
+               wc->src_qp         = g_mlpath_rqpn & 0xffffff;
+               wc->dlid_path_bits = (g_mlpath_rqpn >> 24) & 0x7f;
+               wc->wc_flags      |= g_mlpath_rqpn & 0x80000000 ? IBV_WC_GRH : 0;
                wc->pkey_index     = ntohl(cqe->immed_rss_invalid) >> 16;
-               wc->wc_flags      |= ntohl(cqe->g_mlpath_rqpn) & 0x80000000 ?
-                       IBV_WC_GRH : 0;
        }
 
        return CQ_OK;