socsvn commit: r305575 - soc2016/vincenzo/head/sys/dev/netmap

[vincenzo at FreeBSD.org]

Author: vincenzo
Date: Mon Jun 27 09:33:54 2016
New Revision: 305575
URL: http://svnweb.FreeBSD.org/socsvn/?view=rev&rev=305575

Log:
   freebsd: ptnet_transmit: limit TX batching

Modified:
  soc2016/vincenzo/head/sys/dev/netmap/if_ptnet.c

Modified: soc2016/vincenzo/head/sys/dev/netmap/if_ptnet.c
==============================================================================
--- soc2016/vincenzo/head/sys/dev/netmap/if_ptnet.c	Mon Jun 27 09:33:17 2016	(r305574)
+++ soc2016/vincenzo/head/sys/dev/netmap/if_ptnet.c	Mon Jun 27 09:33:54 2016	(r305575)
@@ -218,6 +218,9 @@
 extern int netmap_initialized;
 
 #define PTNET_BUF_RING_SIZE	4096
+#define PTNET_RX_BUDGET		512
+#define PTNET_TX_BATCH		64
+
 
 static int
 ptnet_attach(device_t dev)
@@ -783,11 +786,36 @@
 	ring->tail = kring->rtail = kring->nr_hwtail;
 }
 
+static void
+ptnet_ring_update(struct ptnet_queue *pq, struct netmap_kring *kring,
+		  unsigned int head)
+{
+	struct netmap_ring *ring = kring->ring;
+	struct ptnet_ring *ptring = pq->ptring;
+
+	/* Some packets have been pushed to the netmap ring. We have
+	 * to tell the host to process the new packets, updating cur
+	 * and head in the CSB. */
+	ring->head = ring->cur = head;
+
+	/* nm_txsync_prologue */
+	kring->rcur = kring->rhead = ring->head;
+
+	ptnetmap_guest_write_kring_csb(ptring, kring->rcur, kring->rhead);
+
+	/* Kick the host if needed. */
+	if (NM_ACCESS_ONCE(ptring->host_need_kick)) {
+		ptring->sync_flags = NAF_FORCE_RECLAIM;
+		bus_write_4(pq->sc->iomem, pq->kick, 0);
+	}
+}
+
 static int
 ptnet_transmit(struct ifnet *ifp, struct mbuf *m)
 {
 	struct ptnet_softc *sc = ifp->if_softc;
 	struct netmap_adapter *na = &sc->ptna_dr.hwup.up;
+	unsigned int batch_count = 0;
 	struct ptnet_ring *ptring;
 	struct netmap_kring *kring;
 	struct netmap_ring *ring;
@@ -896,25 +924,16 @@
 		/* Consume the packet just processed. */
 		drbr_advance(ifp, pq->bufring);
 		m_freem(m);
-	}
-escape:
-	if (head != ring->head) {
-		/* Some packets have been pushed to the netmap ring. We have
-		 * to tell the host to process the new packets, updating cur
-		 * and head in the CSB. */
-		ring->head = ring->cur = head;
-
-		/* nm_txsync_prologue */
-		kring->rcur = kring->rhead = ring->head;
 
-		ptnetmap_guest_write_kring_csb(ptring, kring->rcur, kring->rhead);
-
-		/* Kick the host if needed. */
-		if (NM_ACCESS_ONCE(ptring->host_need_kick)) {
-			ptring->sync_flags = NAF_FORCE_RECLAIM;
-			bus_write_4(sc->iomem, pq->kick, 0);
+		if (++batch_count == PTNET_TX_BATCH) {
+			batch_count = 0;
+			ptnet_ring_update(pq, kring, head);
 		}
 	}
+escape:
+	if (batch_count) {
+		ptnet_ring_update(pq, kring, head);
+	}
 
 	if (head == ring->tail) {
 		/* Reactivate the interrupts so that we can be notified
@@ -1254,8 +1273,6 @@
 	ptnet_rx_eof(pq);
 }
 
-#define RX_BUDGET	512
-
 static int
 ptnet_rx_eof(struct ptnet_queue *pq)
 {
@@ -1265,7 +1282,7 @@
 	struct netmap_kring *kring = na->rx_rings + pq->kring_id;
 	struct netmap_ring *ring = kring->ring;
 	unsigned int const lim = kring->nkr_num_slots - 1;
-	unsigned int budget = RX_BUDGET;
+	unsigned int budget = PTNET_RX_BUDGET;
 	unsigned int head = ring->head;
 	struct ifnet *ifp = sc->ifp;
 	unsigned int more;
@@ -1323,7 +1340,7 @@
 	 * before issuing the last interrupt. */
 	ptring->guest_need_kick = 1;
 
-	if (budget != RX_BUDGET) {
+	if (budget != PTNET_RX_BUDGET) {
 		/* Some packets have been pushed to the network stack.
 		 * We need to update the CSB to tell the host about the new
 		 * ring->cur and ring->head (RX buffer refill). */