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virtio: free mbuf's with threshold

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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: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
Acked-by: Huawei Xie <huawei.xie@intel.com>
This commit is contained in:
Stephen Hemminger 2015-02-09 09:14:05 +08:00 committed by Thomas Monjalon
parent 5186fb1f37
commit 32c118fd00
3 changed files with 62 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
lib/librte_pmd_virtio/virtio_ethdev.c
View File

@ -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];

79
lib/librte_pmd_virtio/virtio_rxtx.c
View File

@ -129,17 +129,32 @@ virtqueue_dequeue_burst_rx(struct virtqueue *vq, struct rte_mbuf **rx_pkts,
return i;
}
static void
virtqueue_dequeue_pkt_tx(struct virtqueue *vq)
{
struct vring_used_elem *uep;
uint16_t used_idx, desc_idx;
#ifndef DEFAULT_TX_FREE_THRESH
#define DEFAULT_TX_FREE_THRESH 32
#endif
used_idx = (uint16_t)(vq->vq_used_cons_idx & (vq->vq_nentries - 1));
uep = &vq->vq_ring.used->ring[used_idx];
desc_idx = (uint16_t) uep->id;
vq->vq_used_cons_idx++;
vq_ring_free_chain(vq, desc_idx);
/* Cleanup from completed transmits. */
static void
virtio_xmit_cleanup(struct virtqueue *vq, uint16_t num)
{
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];
desc_idx = (uint16_t) uep->id;
dxp = &vq->vq_descx[desc_idx];
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 +218,6 @@ virtqueue_enqueue_xmit(struct virtqueue *txvq, struct rte_mbuf *cookie)
idx = head_idx;
dxp = &txvq->vq_descx[idx];
if (dxp->cookie != NULL)
rte_pktmbuf_free(dxp->cookie);
dxp->cookie = (void *)cookie;
dxp->ndescs = needed;
@ -404,6 +417,7 @@ 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 +435,22 @@ 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;
}
@ -691,11 +721,9 @@ 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;
@ -703,21 +731,26 @@ 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.
@ -726,7 +759,7 @@ 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);

3
lib/librte_pmd_virtio/virtqueue.h
View File

@ -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