Backport commit b59cc14e032da370021794bfd1bdd3d67e88a9a3 from master.
This improves latency compared to current openvswitch 2.5.
Without the patch:
Device 0->1:
Throughput: 6.8683 Mpps
Min. Latency: 39.9780 usec
Avg. Latency: 61.1226 usec
Max. Latency: 89.1110 usec
Device 1->0:
Throughput: 6.8683 Mpps
Min. Latency: 41.0660 usec
Avg. Latency: 58.7778 usec
Max. Latency: 89.4720 usec
With the patch:
Device 0->1:
Throughput: 6.3941 Mpps
Min. Latency: 10.5410 usec
Avg. Latency: 14.1309 usec
Max. Latency: 28.9880 usec
Device 1->0:
Throughput: 6.3941 Mpps
Min. Latency: 11.9780 usec
Avg. Latency: 18.0692 usec
Max. Latency: 29.5200
Signed-off-by: Thadeu Lima de Souza Cascardo <casca...@redhat.com>
Cc: Ilya Maximets <i.maxim...@samsung.com>
Cc: Daniele Di Proietto <diproiet...@vmware.com>
---
lib/netdev-dpdk.c | 102 ++++++++----------------------------------------------
1 file changed, 14 insertions(+), 88 deletions(-)
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 6e68c07..cbe361a 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -131,7 +131,6 @@ static const struct rte_eth_conf port_conf = {
},
};
-enum { MAX_TX_QUEUE_LEN = 384 };
enum { DPDK_RING_SIZE = 256 };
BUILD_ASSERT_DECL(IS_POW2(DPDK_RING_SIZE));
enum { DRAIN_TSC = 200000ULL };
@@ -153,8 +152,7 @@ static struct ovs_list dpdk_mp_list
OVS_GUARDED_BY(dpdk_mutex)
= OVS_LIST_INITIALIZER(&dpdk_mp_list);
/* This mutex must be used by non pmd threads when allocating or freeing
- * mbufs through mempools. Since dpdk_queue_pkts() and dpdk_queue_flush() may
- * use mempools, a non pmd thread should hold this mutex while calling them */
+ * mbufs through mempools. */
static struct ovs_mutex nonpmd_mempool_mutex = OVS_MUTEX_INITIALIZER;
struct dpdk_mp {
@@ -168,17 +166,12 @@ struct dpdk_mp {
/* There should be one 'struct dpdk_tx_queue' created for
* each cpu core. */
struct dpdk_tx_queue {
- bool flush_tx; /* Set to true to flush queue everytime */
- /* pkts are queued. */
- int count;
rte_spinlock_t tx_lock; /* Protects the members and the NIC queue
* from concurrent access. It is used only
* if the queue is shared among different
* pmd threads (see 'txq_needs_locking'). */
int map; /* Mapping of configured vhost-user queues
* to enabled by guest. */
- uint64_t tsc;
- struct rte_mbuf *burst_pkts[MAX_TX_QUEUE_LEN];
};
/* dpdk has no way to remove dpdk ring ethernet devices
@@ -566,19 +559,6 @@ netdev_dpdk_alloc_txq(struct netdev_dpdk *netdev, unsigned
int n_txqs)
netdev->tx_q = dpdk_rte_mzalloc(n_txqs * sizeof *netdev->tx_q);
for (i = 0; i < n_txqs; i++) {
- int numa_id = ovs_numa_get_numa_id(i);
-
- if (!netdev->txq_needs_locking) {
- /* Each index is considered as a cpu core id, since there should
- * be one tx queue for each cpu core. If the corresponding core
- * is not on the same numa node as 'netdev', flags the
- * 'flush_tx'. */
- netdev->tx_q[i].flush_tx = netdev->socket_id == numa_id;
- } else {
- /* Queues are shared among CPUs. Always flush */
- netdev->tx_q[i].flush_tx = true;
- }
-
/* Initialize map for vhost devices. */
netdev->tx_q[i].map = OVS_VHOST_QUEUE_MAP_UNKNOWN;
rte_spinlock_init(&netdev->tx_q[i].tx_lock);
@@ -952,16 +932,15 @@ netdev_dpdk_rxq_dealloc(struct netdev_rxq *rxq_)
}
static inline void
-dpdk_queue_flush__(struct netdev_dpdk *dev, int qid)
+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 != txq->count) {
+ while (nb_tx != cnt) {
uint32_t ret;
- ret = rte_eth_tx_burst(dev->port_id, qid, txq->burst_pkts + nb_tx,
- txq->count - nb_tx);
+ ret = rte_eth_tx_burst(dev->port_id, qid, pkts + nb_tx, cnt - nb_tx);
if (!ret) {
break;
}
@@ -969,32 +948,18 @@ dpdk_queue_flush__(struct netdev_dpdk *dev, int qid)
nb_tx += ret;
}
- if (OVS_UNLIKELY(nb_tx != txq->count)) {
+ if (OVS_UNLIKELY(nb_tx != cnt)) {
/* free buffers, which we couldn't transmit, one at a time (each
* packet could come from a different mempool) */
int i;
- for (i = nb_tx; i < txq->count; i++) {
- rte_pktmbuf_free(txq->burst_pkts[i]);
+ for (i = nb_tx; i < cnt; i++) {
+ rte_pktmbuf_free(pkts[i]);
}
rte_spinlock_lock(&dev->stats_lock);
- dev->stats.tx_dropped += txq->count-nb_tx;
+ dev->stats.tx_dropped += cnt - nb_tx;
rte_spinlock_unlock(&dev->stats_lock);
}
-
- txq->count = 0;
- txq->tsc = rte_get_timer_cycles();
-}
-
-static inline void
-dpdk_queue_flush(struct netdev_dpdk *dev, int qid)
-{
- struct dpdk_tx_queue *txq = &dev->tx_q[qid];
-
- if (txq->count == 0) {
- return;
- }
- dpdk_queue_flush__(dev, qid);
}
static bool
@@ -1080,15 +1045,6 @@ netdev_dpdk_rxq_recv(struct netdev_rxq *rxq_, struct
dp_packet **packets,
struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
int nb_rx;
- /* There is only one tx queue for this core. Do not flush other
- * queues.
- * Do not flush tx queue which is shared among CPUs
- * since it is always flushed */
- if (rxq_->queue_id == rte_lcore_id() &&
- OVS_LIKELY(!dev->txq_needs_locking)) {
- dpdk_queue_flush(dev, rxq_->queue_id);
- }
-
nb_rx = rte_eth_rx_burst(rx->port_id, rxq_->queue_id,
(struct rte_mbuf **) packets,
NETDEV_MAX_BURST);
@@ -1175,35 +1131,6 @@ out:
}
}
-inline static void
-dpdk_queue_pkts(struct netdev_dpdk *dev, int qid,
- struct rte_mbuf **pkts, int cnt)
-{
- struct dpdk_tx_queue *txq = &dev->tx_q[qid];
- uint64_t diff_tsc;
-
- int i = 0;
-
- while (i < cnt) {
- int freeslots = MAX_TX_QUEUE_LEN - txq->count;
- int tocopy = MIN(freeslots, cnt-i);
-
- memcpy(&txq->burst_pkts[txq->count], &pkts[i],
- tocopy * sizeof (struct rte_mbuf *));
-
- txq->count += tocopy;
- i += tocopy;
-
- if (txq->count == MAX_TX_QUEUE_LEN || txq->flush_tx) {
- dpdk_queue_flush__(dev, qid);
- }
- diff_tsc = rte_get_timer_cycles() - txq->tsc;
- if (diff_tsc >= DRAIN_TSC) {
- dpdk_queue_flush__(dev, qid);
- }
- }
-}
-
/* Tx function. Transmit packets indefinitely */
static void
dpdk_do_tx_copy(struct netdev *netdev, int qid, struct dp_packet **pkts,
@@ -1265,8 +1192,7 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct
dp_packet **pkts,
if (dev->type == DPDK_DEV_VHOST) {
__netdev_dpdk_vhost_send(netdev, qid, (struct dp_packet **) mbufs,
newcnt, true);
} else {
- dpdk_queue_pkts(dev, qid, mbufs, newcnt);
- dpdk_queue_flush(dev, qid);
+ netdev_dpdk_eth_tx_burst(dev, qid, mbufs, newcnt);
}
if (!dpdk_thread_is_pmd()) {
@@ -1324,7 +1250,7 @@ netdev_dpdk_send__(struct netdev_dpdk *dev, int qid,
if (OVS_UNLIKELY(size > dev->max_packet_len)) {
if (next_tx_idx != i) {
- dpdk_queue_pkts(dev, qid,
+ netdev_dpdk_eth_tx_burst(dev, qid,
(struct rte_mbuf **)&pkts[next_tx_idx],
i-next_tx_idx);
}
@@ -1338,9 +1264,9 @@ netdev_dpdk_send__(struct netdev_dpdk *dev, int qid,
}
}
if (next_tx_idx != cnt) {
- dpdk_queue_pkts(dev, qid,
- (struct rte_mbuf **)&pkts[next_tx_idx],
- cnt-next_tx_idx);
+ netdev_dpdk_eth_tx_burst(dev, qid,
+ (struct rte_mbuf **)&pkts[next_tx_idx],
+ cnt-next_tx_idx);
}
if (OVS_UNLIKELY(dropped)) {
--
2.7.4
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