[dpdk-dev] [PATCH v3 2/2] driver/net/mpipe: some code optimization

[Liming Sun]

This commit includes two small code optimization.
1. use __insn_fetchadd4() instead of rte_atomic32_xxx() in
   mpipe_dp_enter/mpipe_dp_exit to avoid the nnecessary memory
   fence.
2. replace the calling of rte_pktmbuf_reset() in mpipe_recv_mbuf()
   with specific code to avoid some duplicated initializations.
---
 drivers/net/mpipe/mpipe_tilegx.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/net/mpipe/mpipe_tilegx.c b/drivers/net/mpipe/mpipe_tilegx.c
index 5845511..8d006fa 100644
--- a/drivers/net/mpipe/mpipe_tilegx.c
+++ b/drivers/net/mpipe/mpipe_tilegx.c
@@ -451,13 +451,13 @@ static inline void
 mpipe_dp_enter(struct mpipe_dev_priv *priv)
 {
        __insn_mtspr(SPR_DSTREAM_PF, 0);
-       rte_atomic32_inc(&priv->dp_count);
+       __insn_fetchadd4(&priv->dp_count, 1);
 }

 static inline void
 mpipe_dp_exit(struct mpipe_dev_priv *priv)
 {
-       rte_atomic32_dec(&priv->dp_count);
+       __insn_fetchadd4(&priv->dp_count, -1);
 }

 static inline void
@@ -484,12 +484,20 @@ mpipe_recv_mbuf(struct mpipe_dev_priv *priv, 
gxio_mpipe_idesc_t *idesc,
        uint16_t size = gxio_mpipe_idesc_get_xfer_size(idesc);
        struct rte_mbuf *mbuf = RTE_PTR_SUB(va, priv->rx_offset);

-       rte_pktmbuf_reset(mbuf);
        mbuf->data_off = (uintptr_t)va - (uintptr_t)mbuf->buf_addr;
-       mbuf->port     = in_port;
-       mbuf->data_len = size;
+       mbuf->nb_segs = 1;
+       mbuf->port = in_port;
+       mbuf->ol_flags = 0;
+       if (gxio_mpipe_idesc_get_ethertype(idesc) == ETHER_TYPE_IPv4)
+               mbuf->packet_type = RTE_PTYPE_L3_IPV4 | RTE_PTYPE_L2_ETHER;
+       else if (gxio_mpipe_idesc_get_ethertype(idesc) == ETHER_TYPE_IPv6)
+               mbuf->packet_type = RTE_PTYPE_L3_IPV6 | RTE_PTYPE_L2_ETHER;
+       else
+               mbuf->packet_type = RTE_PTYPE_UNKNOWN;
        mbuf->pkt_len  = size;
+       mbuf->data_len = size;
        mbuf->hash.rss = gxio_mpipe_idesc_get_flow_hash(idesc);
+       mbuf->next = NULL;

        PMD_DEBUG_RX("%s: RX mbuf %p, buffer %p, buf_addr %p, size %d\n",
                     mpipe_name(priv), mbuf, va, mbuf->buf_addr, size);
-- 
1.8.3.1