[ovs-dev] [PATCH v4 3/5] netdev-dpdk: Add intermediate queue support.
Bhanuprakash Bodireddy
bhanuprakash.bodireddy at intel.com
Tue Aug 8 17:06:14 UTC 2017
This commit introduces netdev_dpdk_eth_tx_queue() function that
implements intermediate queue and packet buffering. The packets get
buffered till the threshold 'INTERIM_QUEUE_BURST_THRESHOLD[32] is
reached and eventually gets transmitted.
Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy at intel.com>
Signed-off-by: Antonio Fischetti <antonio.fischetti at intel.com>
Co-authored-by: Antonio Fischetti <antonio.fischetti at intel.com>
Signed-off-by: Markus Magnusson <markus.magnusson at ericsson.com>
Co-authored-by: Markus Magnusson <markus.magnusson at ericsson.com>
Acked-by: Eelco Chaudron <echaudro at redhat.com>
---
lib/netdev-dpdk.c | 37 +++++++++++++++++++++++++++++++++++--
1 file changed, 35 insertions(+), 2 deletions(-)
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index d3892fe..b4dc36a 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -1483,6 +1483,7 @@ static inline int
netdev_dpdk_eth_tx_burst(struct netdev_dpdk *dev, int qid,
struct rte_mbuf **pkts, int cnt)
{
+ struct dpdk_tx_queue *txq = &dev->tx_q[qid];
uint32_t nb_tx = 0;
while (nb_tx != cnt) {
@@ -1506,6 +1507,7 @@ netdev_dpdk_eth_tx_burst(struct netdev_dpdk *dev, int qid,
}
}
+ txq->dpdk_pkt_cnt = 0;
return cnt - nb_tx;
}
@@ -1905,6 +1907,37 @@ out:
}
}
+/* Enqueue packets in an intermediate queue and call the flush
+ * function when the queue is full. This way we can amortize the
+ * cost of MMIO writes. */
+static inline int
+netdev_dpdk_eth_tx_queue(struct netdev_dpdk *dev, int qid,
+ struct rte_mbuf **pkts, int cnt)
+{
+ struct dpdk_tx_queue *txq = &dev->tx_q[qid];
+
+ int i = 0;
+ int dropped = 0;
+
+ while (i < cnt) {
+ int freeslots = INTERIM_QUEUE_BURST_THRESHOLD - txq->dpdk_pkt_cnt;
+ int tocopy = MIN(freeslots, cnt-i);
+
+ memcpy(&txq->dpdk_burst_pkts[txq->dpdk_pkt_cnt], &pkts[i],
+ tocopy * sizeof (struct rte_mbuf *));
+
+ txq->dpdk_pkt_cnt += tocopy;
+ i += tocopy;
+
+ /* Queue full, burst the packets. */
+ if (txq->dpdk_pkt_cnt >= INTERIM_QUEUE_BURST_THRESHOLD) {
+ dropped += netdev_dpdk_eth_tx_burst(dev, qid, txq->dpdk_burst_pkts,
+ txq->dpdk_pkt_cnt);
+ }
+ }
+ return dropped;
+}
+
/* Tx function. Transmit packets indefinitely */
static void
dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet_batch *batch)
@@ -1962,7 +1995,7 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet_batch *batch)
newcnt = netdev_dpdk_qos_run(dev, pkts, newcnt);
dropped += qos_pkts - newcnt;
- dropped += netdev_dpdk_eth_tx_burst(dev, qid, pkts, newcnt);
+ dropped += netdev_dpdk_eth_tx_queue(dev, qid, pkts, newcnt);
}
if (OVS_UNLIKELY(dropped)) {
@@ -2020,7 +2053,7 @@ netdev_dpdk_send__(struct netdev_dpdk *dev, int qid,
cnt = netdev_dpdk_qos_run(dev, pkts, cnt);
dropped = batch->count - cnt;
- dropped += netdev_dpdk_eth_tx_burst(dev, qid, pkts, cnt);
+ dropped += netdev_dpdk_eth_tx_queue(dev, qid, pkts, cnt);
if (OVS_UNLIKELY(dropped)) {
rte_spinlock_lock(&dev->stats_lock);
--
2.4.11
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