[dpdk-dev] [PATCH v3 4/4] port: added ring_writer_nodrop port

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

When ring_writer_nodrop port fails to send data, it tries to resend.
Operation is aborted when maximum number of retries is reached.

Signed-off-by: Maciej Gajdzica <maciejx.t.gajdzica@intel.com>
---
 lib/librte_port/rte_port_ring.c |  179 +++++++++++++++++++++++++++++++++++++++
 lib/librte_port/rte_port_ring.h |   16 ++++
 2 files changed, 195 insertions(+)

diff --git a/lib/librte_port/rte_port_ring.c b/lib/librte_port/rte_port_ring.c
index ba1fdcb..89b9641 100644
--- a/lib/librte_port/rte_port_ring.c
+++ b/lib/librte_port/rte_port_ring.c
@@ -31,6 +31,7 @@
  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include <string.h>
+#include <stdint.h>
 
 #include <rte_mbuf.h>
 #include <rte_ring.h>
@@ -233,6 +234,176 @@ rte_port_ring_writer_free(void *port)
 }
 
 /*
+ * Port RING Writer Nodrop
+ */
+struct rte_port_ring_writer_nodrop {
+	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;
+	uint64_t n_retries;
+};
+
+static void *
+rte_port_ring_writer_nodrop_create(void *params, int socket_id)
+{
+	struct rte_port_ring_writer_nodrop_params *conf =
+			(struct rte_port_ring_writer_nodrop_params *) params;
+	struct rte_port_ring_writer_nodrop *port;
+
+	/* Check input parameters */
+	if ((conf == NULL) ||
+	    (conf->ring == NULL) ||
+		(conf->tx_burst_sz > RTE_PORT_IN_BURST_SIZE_MAX)) {
+		RTE_LOG(ERR, PORT, "%s: Invalid Parameters\n", __func__);
+		return NULL;
+	}
+
+	/* Memory allocation */
+	port = rte_zmalloc_socket("PORT", sizeof(*port),
+			RTE_CACHE_LINE_SIZE, socket_id);
+	if (port == NULL) {
+		RTE_LOG(ERR, PORT, "%s: Failed to allocate port\n", __func__);
+		return NULL;
+	}
+
+	/* Initialization */
+	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);
+
+	/*
+	 * When n_retries is 0 it means that we should wait for every packet to
+	 * send no matter how many retries should it take. To limit number of
+	 * branches in fast path, we use UINT64_MAX instead of branching.
+	 */
+	port->n_retries = (conf->n_retries == 0) ? UINT64_MAX : conf->n_retries;
+
+	return port;
+}
+
+static inline void
+send_burst_nodrop(struct rte_port_ring_writer_nodrop *p)
+{
+	uint32_t nb_tx = 0, i;
+
+	nb_tx = rte_ring_sp_enqueue_burst(p->ring, (void **)p->tx_buf,
+				p->tx_buf_count);
+
+	/* We sent all the packets in a first try */
+	if (nb_tx >= p->tx_buf_count)
+		return;
+
+	for (i = 0; i < p->n_retries; i++) {
+		nb_tx += rte_ring_sp_enqueue_burst(p->ring,
+				(void **) (p->tx_buf + nb_tx), p->tx_buf_count - nb_tx);
+
+		/* We sent all the packets in more than one try */
+		if (nb_tx >= p->tx_buf_count)
+			return;
+	}
+
+	/* We didn't send the packets in maximum allowed attempts */
+	for ( ; nb_tx < p->tx_buf_count; nb_tx++)
+		rte_pktmbuf_free(p->tx_buf[nb_tx]);
+
+	p->tx_buf_count = 0;
+}
+
+static int
+rte_port_ring_writer_nodrop_tx(void *port, struct rte_mbuf *pkt)
+{
+	struct rte_port_ring_writer_nodrop *p =
+			(struct rte_port_ring_writer_nodrop *) port;
+
+	p->tx_buf[p->tx_buf_count++] = pkt;
+	if (p->tx_buf_count >= p->tx_burst_sz)
+		send_burst_nodrop(p);
+
+	return 0;
+}
+
+static int
+rte_port_ring_writer_nodrop_tx_bulk(void *port,
+		struct rte_mbuf **pkts,
+		uint64_t pkts_mask)
+{
+	struct rte_port_ring_writer_nodrop *p =
+		(struct rte_port_ring_writer_nodrop *) 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_nodrop(p);
+
+		n_pkts_ok = rte_ring_sp_enqueue_burst(p->ring, (void **)pkts, n_pkts);
+
+		if (n_pkts_ok >= n_pkts)
+			return 0;
+
+		/*
+		 * If we didnt manage to send all packets in single burst, move
+		 * remaining packets to the buffer and call send burst.
+		 */
+		for (; n_pkts_ok < n_pkts; n_pkts_ok++) {
+			struct rte_mbuf *pkt = pkts[n_pkts_ok];
+			p->tx_buf[p->tx_buf_count++] = pkt;
+		}
+		send_burst_nodrop(p);
+	} 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_nodrop(p);
+	}
+
+	return 0;
+}
+
+static int
+rte_port_ring_writer_nodrop_flush(void *port)
+{
+	struct rte_port_ring_writer_nodrop *p =
+			(struct rte_port_ring_writer_nodrop *) port;
+
+	if (p->tx_buf_count > 0)
+		send_burst_nodrop(p);
+
+	return 0;
+}
+
+static int
+rte_port_ring_writer_nodrop_free(void *port)
+{
+	if (port == NULL) {
+		RTE_LOG(ERR, PORT, "%s: Port is NULL\n", __func__);
+		return -EINVAL;
+	}
+
+	rte_port_ring_writer_nodrop_flush(port);
+	rte_free(port);
+
+	return 0;
+}
+
+/*
  * Summary of port operations
  */
 struct rte_port_in_ops rte_port_ring_reader_ops = {
@@ -248,3 +419,11 @@ struct rte_port_out_ops rte_port_ring_writer_ops = {
 	.f_tx_bulk = rte_port_ring_writer_tx_bulk,
 	.f_flush = rte_port_ring_writer_flush,
 };
+
+struct rte_port_out_ops rte_port_ring_writer_nodrop_ops = {
+	.f_create = rte_port_ring_writer_nodrop_create,
+	.f_free = rte_port_ring_writer_nodrop_free,
+	.f_tx = rte_port_ring_writer_nodrop_tx,
+	.f_tx_bulk = rte_port_ring_writer_nodrop_tx_bulk,
+	.f_flush = rte_port_ring_writer_nodrop_flush,
+};
diff --git a/lib/librte_port/rte_port_ring.h b/lib/librte_port/rte_port_ring.h
index 009dcf8..89a219b 100644
--- a/lib/librte_port/rte_port_ring.h
+++ b/lib/librte_port/rte_port_ring.h
@@ -75,6 +75,22 @@ struct rte_port_ring_writer_params {
 /** ring_writer port operations */
 extern struct rte_port_out_ops rte_port_ring_writer_ops;
 
+/** ring_writer_nodrop port parameters */
+struct rte_port_ring_writer_nodrop_params {
+	/** Underlying single producer ring that has to be pre-initialized */
+	struct rte_ring *ring;
+
+	/** Recommended burst size to ring. The actual burst size can be
+		bigger or smaller than this value. */
+	uint32_t tx_burst_sz;
+
+	/** Maximum number of retries, 0 for no limit */
+	uint32_t n_retries;
+};
+
+/** ring_writer_nodrop port operations */
+extern struct rte_port_out_ops rte_port_ring_writer_nodrop_ops;
+
 #ifdef __cplusplus
 }
 #endif
-- 
1.7.9.5