This makes virtio driver work like ixgbe. Transmit buffers are
held until a transmit threshold is reached. The previous behavior
was to hold mbuf's until the ring entry was reused which caused
more memory usage than needed.
Signed-off-by: Changchun Ouyang <changchun.ouyang at intel.com>
Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
lib/librte_pmd_virtio/virtio_ethdev.c | 7 ++--
lib/librte_pmd_virtio/virtio_rxtx.c | 70 +++++++++++++++++++++++++++++------
lib/librte_pmd_virtio/virtqueue.h | 3 +-
3 files changed, 64 insertions(+), 16 deletions(-)
diff --git a/lib/librte_pmd_virtio/virtio_ethdev.c
b/lib/librte_pmd_virtio/virtio_ethdev.c
index c5f21c1..1ec29e1 100644
--- a/lib/librte_pmd_virtio/virtio_ethdev.c
+++ b/lib/librte_pmd_virtio/virtio_ethdev.c
@@ -176,15 +176,16 @@ virtio_send_command(struct virtqueue *vq, struct
virtio_pmd_ctrl *ctrl,
virtqueue_notify(vq);
- while (vq->vq_used_cons_idx == vq->vq_ring.used->idx)
+ rte_rmb();
+ while (vq->vq_used_cons_idx == vq->vq_ring.used->idx) {
+ rte_rmb();
usleep(100);
+ }
while (vq->vq_used_cons_idx != vq->vq_ring.used->idx) {
uint32_t idx, desc_idx, used_idx;
struct vring_used_elem *uep;
- virtio_rmb();
-
used_idx = (uint32_t)(vq->vq_used_cons_idx
& (vq->vq_nentries - 1));
uep = &vq->vq_ring.used->ring[used_idx];
diff --git a/lib/librte_pmd_virtio/virtio_rxtx.c
b/lib/librte_pmd_virtio/virtio_rxtx.c
index b44f091..26c0a1d 100644
--- a/lib/librte_pmd_virtio/virtio_rxtx.c
+++ b/lib/librte_pmd_virtio/virtio_rxtx.c
@@ -129,9 +129,15 @@ virtqueue_dequeue_burst_rx(struct virtqueue *vq, struct
rte_mbuf **rx_pkts,
return i;
}
+#ifndef DEFAULT_TX_FREE_THRESH
+#define DEFAULT_TX_FREE_THRESH 32
+#endif
+
+/* Cleanup from completed transmits. */
static void
-virtqueue_dequeue_pkt_tx(struct virtqueue *vq)
+virtio_xmit_cleanup(struct virtqueue *vq, uint16_t num)
{
+#if 0
struct vring_used_elem *uep;
uint16_t used_idx, desc_idx;
@@ -140,6 +146,25 @@ virtqueue_dequeue_pkt_tx(struct virtqueue *vq)
desc_idx = (uint16_t) uep->id;
vq->vq_used_cons_idx++;
vq_ring_free_chain(vq, desc_idx);
+#endif
+ uint16_t i, used_idx, desc_idx;
+ for (i = 0; i < num ; i++) {
+ struct vring_used_elem *uep;
+ struct vq_desc_extra *dxp;
+
+ used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries -
1));
+ uep = &vq->vq_ring.used->ring[used_idx];
+ dxp = &vq->vq_descx[used_idx];
+
+ desc_idx = (uint16_t) uep->id;
+ vq->vq_used_cons_idx++;
+ vq_ring_free_chain(vq, desc_idx);
+
+ if (dxp->cookie != NULL) {
+ rte_pktmbuf_free(dxp->cookie);
+ dxp->cookie = NULL;
+ }
+ }
}
@@ -203,8 +228,10 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct
rte_mbuf *cookie)
idx = head_idx;
dxp = &txvq->vq_descx[idx];
+#if 0
if (dxp->cookie != NULL)
rte_pktmbuf_free(dxp->cookie);
+#endif
dxp->cookie = (void *)cookie;
dxp->ndescs = needed;
@@ -404,6 +431,7 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
{
uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
struct virtqueue *vq;
+ uint16_t tx_free_thresh;
int ret;
PMD_INIT_FUNC_TRACE();
@@ -421,6 +449,21 @@ virtio_dev_tx_queue_setup(struct rte_eth_dev *dev,
return ret;
}
+ tx_free_thresh = tx_conf->tx_free_thresh;
+ if (tx_free_thresh == 0)
+ tx_free_thresh = RTE_MIN(vq->vq_nentries / 4,
DEFAULT_TX_FREE_THRESH);
+
+ if (tx_free_thresh >= (vq->vq_nentries - 3)) {
+ RTE_LOG(ERR, PMD, "tx_free_thresh must be less than the "
+ "number of TX entries minus 3 (%u)."
+ " (tx_free_thresh=%u port=%u queue=%u)\n",
+ vq->vq_nentries - 3,
+ tx_free_thresh, dev->data->port_id, queue_idx);
+ return -EINVAL;
+ }
+
+ vq->vq_free_thresh = tx_free_thresh;
+
dev->data->tx_queues[queue_idx] = vq;
return 0;
}
@@ -688,11 +731,9 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf
**tx_pkts, uint16_t nb_pkts)
{
struct virtqueue *txvq = tx_queue;
struct rte_mbuf *txm;
- uint16_t nb_used, nb_tx, num;
+ uint16_t nb_used, nb_tx;
int error;
- nb_tx = 0;
-
if (unlikely(nb_pkts < 1))
return nb_pkts;
@@ -700,21 +741,26 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf
**tx_pkts, uint16_t nb_pkts)
nb_used = VIRTQUEUE_NUSED(txvq);
virtio_rmb();
+ if (likely(nb_used > txvq->vq_free_thresh))
+ virtio_xmit_cleanup(txvq, nb_used);
- num = (uint16_t)(likely(nb_used < VIRTIO_MBUF_BURST_SZ) ? nb_used :
VIRTIO_MBUF_BURST_SZ);
+ nb_tx = 0;
while (nb_tx < nb_pkts) {
/* Need one more descriptor for virtio header. */
int need = tx_pkts[nb_tx]->nb_segs - txvq->vq_free_cnt + 1;
- int deq_cnt = RTE_MIN(need, (int)num);
- num -= (deq_cnt > 0) ? deq_cnt : 0;
- while (deq_cnt > 0) {
- virtqueue_dequeue_pkt_tx(txvq);
- deq_cnt--;
+ /*Positive value indicates it need free vring descriptors */
+ if (unlikely(need > 0)) {
+ nb_used = VIRTQUEUE_NUSED(txvq);
+ virtio_rmb();
+ need = RTE_MIN(need, (int)nb_used);
+
+ virtio_xmit_cleanup(txvq, need);
+ need = (int)tx_pkts[nb_tx]->nb_segs -
+ txvq->vq_free_cnt + 1;
}
- need = (int)tx_pkts[nb_tx]->nb_segs - txvq->vq_free_cnt + 1;
/*
* Zero or negative value indicates it has enough free
* descriptors to use for transmitting.
@@ -723,7 +769,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
uint16_t nb_pkts)
txm = tx_pkts[nb_tx];
/* Do VLAN tag insertion */
- if (txm->ol_flags & PKT_TX_VLAN_PKT) {
+ if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
error = rte_vlan_insert(&txm);
if (unlikely(error)) {
rte_pktmbuf_free(txm);
diff --git a/lib/librte_pmd_virtio/virtqueue.h
b/lib/librte_pmd_virtio/virtqueue.h
index 4cb82f9..7672a12 100644
--- a/lib/librte_pmd_virtio/virtqueue.h
+++ b/lib/librte_pmd_virtio/virtqueue.h
@@ -164,6 +164,7 @@ struct virtqueue {
struct rte_mempool *mpool; /**< mempool for mbuf allocation */
uint16_t queue_id; /**< DPDK queue index. */
uint8_t port_id; /**< Device port identifier. */
+ uint16_t vq_queue_index; /**< PCI queue index */
void *vq_ring_virt_mem; /**< linear address of vring*/
unsigned int vq_ring_size;
@@ -172,7 +173,7 @@ struct virtqueue {
struct vring vq_ring; /**< vring keeping desc, used and avail */
uint16_t vq_free_cnt; /**< num of desc available */
uint16_t vq_nentries; /**< vring desc numbers */
- uint16_t vq_queue_index; /**< PCI queue index */
+ uint16_t vq_free_thresh; /**< free threshold */
/**
* Head of the free chain in the descriptor table. If
* there are no free descriptors, this will be set to
--
1.8.4.2
