[dpdk-dev] [PATCH 1/3] port: added WRITER_APPROACH == 1 implementation to ring port

[Maciej Gajdzica <maciejx.t.gajdzica@intel.com>]

Added better optimized implementation of tx_bulk for ring writer port based on
similar solution in ethdev_writer port. New implementation sends burst without
copying data to internal buffer if it is possible.
 
---
 lib/librte_port/rte_port_ring.c |   59 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/lib/librte_port/rte_port_ring.c b/lib/librte_port/rte_port_ring.c
index fa3d77b..ba2eeb3 100644
--- a/lib/librte_port/rte_port_ring.c
+++ b/lib/librte_port/rte_port_ring.c
@@ -96,11 +96,14 @@ rte_port_ring_reader_free(void *port)
 /*
  * Port RING Writer
  */
+#define RTE_PORT_RING_WRITER_APPROACH                  1
+
 struct rte_port_ring_writer {
 	struct rte_mbuf *tx_buf[RTE_PORT_IN_BURST_SIZE_MAX];
 	struct rte_ring *ring;
 	uint32_t tx_burst_sz;
 	uint32_t tx_buf_count;
+	uint64_t bsz_mask;
 };
 
 static void *
@@ -130,6 +133,7 @@ rte_port_ring_writer_create(void *params, int socket_id)
 	port->ring = conf->ring;
 	port->tx_burst_sz = conf->tx_burst_sz;
 	port->tx_buf_count = 0;
+	port->bsz_mask = 1LLU << (conf->tx_burst_sz - 1);
 
 	return port;
 }
@@ -160,6 +164,8 @@ rte_port_ring_writer_tx(void *port, struct rte_mbuf *pkt)
 	return 0;
 }
 
+#if RTE_PORT_RING_WRITER_APPROACH == 0
+
 static int
 rte_port_ring_writer_tx_bulk(void *port,
 		struct rte_mbuf **pkts,
@@ -194,6 +200,59 @@ rte_port_ring_writer_tx_bulk(void *port,
 	return 0;
 }
 
+#elif RTE_PORT_RING_WRITER_APPROACH == 1
+
+static int
+rte_port_ring_writer_tx_bulk(void *port,
+		struct rte_mbuf **pkts,
+		uint64_t pkts_mask)
+{
+	struct rte_port_ring_writer *p =
+		(struct rte_port_ring_writer *) port;
+
+	uint32_t bsz_mask = p->bsz_mask;
+	uint32_t tx_buf_count = p->tx_buf_count;
+	uint64_t expr = (pkts_mask & (pkts_mask + 1)) |
+			((pkts_mask & bsz_mask) ^ bsz_mask);
+
+	if (expr == 0) {
+		uint64_t n_pkts = __builtin_popcountll(pkts_mask);
+		uint32_t n_pkts_ok;
+
+		if (tx_buf_count)
+			send_burst(p);
+
+		n_pkts_ok = rte_ring_sp_enqueue_burst(p->ring, (void **)pkts, n_pkts);
+
+		for ( ; n_pkts_ok < n_pkts; n_pkts_ok++) {
+			struct rte_mbuf *pkt = pkts[n_pkts_ok];
+
+			rte_pktmbuf_free(pkt);
+		}
+	} else {
+		for ( ; pkts_mask; ) {
+			uint32_t pkt_index = __builtin_ctzll(pkts_mask);
+			uint64_t pkt_mask = 1LLU << pkt_index;
+			struct rte_mbuf *pkt = pkts[pkt_index];
+
+			p->tx_buf[tx_buf_count++] = pkt;
+			pkts_mask &= ~pkt_mask;
+		}
+
+		p->tx_buf_count = tx_buf_count;
+		if (tx_buf_count >= p->tx_burst_sz)
+			send_burst(p);
+	}
+
+	return 0;
+}
+
+#else
+
+#error Invalid value for RTE_PORT_RING_WRITER_APPROACH
+
+#endif
+
 static int
 rte_port_ring_writer_flush(void *port)
 {
-- 
1.7.9.5