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net/virtio: optimize flags update for packed ring

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Cache the AVAIL, USED and WRITE bits to avoid calculating
them as much as possible. Note that, the WRITE bit isn't
cached for control queue.

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Jens Freimann <jfreimann@redhat.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
This commit is contained in:
Tiwei Bie 2019-03-19 14:43:06 +08:00 committed by Ferruh Yigit
parent 8f66bc4ac3
commit 8e148e4920
3 changed files with 32 additions and 42 deletions
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35
drivers/net/virtio/virtio_ethdev.c
View File

@ -149,7 +149,7 @@ virtio_send_command_packed(struct virtnet_ctl *cvq,
int head;
struct vring_packed_desc *desc = vq->ring_packed.desc_packed;
struct virtio_pmd_ctrl *result;
bool avail_wrap_counter;
uint16_t flags;
int sum = 0;
int nb_descs = 0;
int k;
@ -161,14 +161,15 @@ virtio_send_command_packed(struct virtnet_ctl *cvq,
* One RX packet for ACK.
*/
head = vq->vq_avail_idx;
avail_wrap_counter = vq->avail_wrap_counter;
flags = vq->cached_flags;
desc[head].addr = cvq->virtio_net_hdr_mem;
desc[head].len = sizeof(struct virtio_net_ctrl_hdr);
vq->vq_free_cnt--;
nb_descs++;
if (++vq->vq_avail_idx >= vq->vq_nentries) {
vq->vq_avail_idx -= vq->vq_nentries;
vq->avail_wrap_counter ^= 1;
vq->cached_flags ^=
VRING_DESC_F_AVAIL(1) | VRING_DESC_F_USED(1);
}
for (k = 0; k < pkt_num; k++) {
@ -177,34 +178,31 @@ virtio_send_command_packed(struct virtnet_ctl *cvq,
+ sizeof(ctrl->status) + sizeof(uint8_t) * sum;
desc[vq->vq_avail_idx].len = dlen[k];
desc[vq->vq_avail_idx].flags = VRING_DESC_F_NEXT |
VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
VRING_DESC_F_USED(!vq->avail_wrap_counter);
vq->cached_flags;
sum += dlen[k];
vq->vq_free_cnt--;
nb_descs++;
if (++vq->vq_avail_idx >= vq->vq_nentries) {
vq->vq_avail_idx -= vq->vq_nentries;
vq->avail_wrap_counter ^= 1;
vq->cached_flags ^=
VRING_DESC_F_AVAIL(1) | VRING_DESC_F_USED(1);
}
}
desc[vq->vq_avail_idx].addr = cvq->virtio_net_hdr_mem
+ sizeof(struct virtio_net_ctrl_hdr);
desc[vq->vq_avail_idx].len = sizeof(ctrl->status);
desc[vq->vq_avail_idx].flags = VRING_DESC_F_WRITE |
VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
VRING_DESC_F_USED(!vq->avail_wrap_counter);
desc[vq->vq_avail_idx].flags = VRING_DESC_F_WRITE | vq->cached_flags;
vq->vq_free_cnt--;
nb_descs++;
if (++vq->vq_avail_idx >= vq->vq_nentries) {
vq->vq_avail_idx -= vq->vq_nentries;
vq->avail_wrap_counter ^= 1;
vq->cached_flags ^=
VRING_DESC_F_AVAIL(1) | VRING_DESC_F_USED(1);
}
virtio_wmb(vq->hw->weak_barriers);
desc[head].flags = VRING_DESC_F_NEXT |
VRING_DESC_F_AVAIL(avail_wrap_counter) |
VRING_DESC_F_USED(!avail_wrap_counter);
desc[head].flags = VRING_DESC_F_NEXT | flags;
virtio_wmb(vq->hw->weak_barriers);
virtqueue_notify(vq);
@ -226,12 +224,12 @@ virtio_send_command_packed(struct virtnet_ctl *cvq,
PMD_INIT_LOG(DEBUG, "vq->vq_free_cnt=%d\n"
"vq->vq_avail_idx=%d\n"
"vq->vq_used_cons_idx=%d\n"
"vq->avail_wrap_counter=%d\n"
"vq->cached_flags=0x%x\n"
"vq->used_wrap_counter=%d\n",
vq->vq_free_cnt,
vq->vq_avail_idx,
vq->vq_used_cons_idx,
vq->avail_wrap_counter,
vq->cached_flags,
vq->used_wrap_counter);
result = cvq->virtio_net_hdr_mz->addr;
@ -491,11 +489,10 @@ virtio_init_queue(struct rte_eth_dev *dev, uint16_t vtpci_queue_idx)
vq->vq_nentries = vq_size;
vq->event_flags_shadow = 0;
if (vtpci_packed_queue(hw)) {
vq->avail_wrap_counter = 1;
vq->used_wrap_counter = 1;
vq->avail_used_flags =
VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
VRING_DESC_F_USED(!vq->avail_wrap_counter);
vq->cached_flags = VRING_DESC_F_AVAIL(1);
if (queue_type == VTNET_RQ)
vq->cached_flags |= VRING_DESC_F_WRITE;
}
/*

31
drivers/net/virtio/virtio_rxtx.c
View File

@ -431,7 +431,7 @@ virtqueue_enqueue_recv_refill_packed(struct virtqueue *vq,
struct rte_mbuf **cookie, uint16_t num)
{
struct vring_packed_desc *start_dp = vq->ring_packed.desc_packed;
uint16_t flags = VRING_DESC_F_WRITE | vq->avail_used_flags;
uint16_t flags = vq->cached_flags;
struct virtio_hw *hw = vq->hw;
struct vq_desc_extra *dxp;
uint16_t idx;
@ -460,11 +460,9 @@ virtqueue_enqueue_recv_refill_packed(struct virtqueue *vq,
start_dp[idx].flags = flags;
if (++vq->vq_avail_idx >= vq->vq_nentries) {
vq->vq_avail_idx -= vq->vq_nentries;
vq->avail_wrap_counter ^= 1;
vq->avail_used_flags =
VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
VRING_DESC_F_USED(!vq->avail_wrap_counter);
flags = VRING_DESC_F_WRITE | vq->avail_used_flags;
vq->cached_flags ^=
VRING_DESC_F_AVAIL(1) | VRING_DESC_F_USED(1);
flags = vq->cached_flags;
}
}
vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - num);
@ -643,7 +641,7 @@ virtqueue_enqueue_xmit_packed_fast(struct virtnet_tx *txvq,
dxp->ndescs = 1;
dxp->cookie = cookie;
flags = vq->avail_used_flags;
flags = vq->cached_flags;
/* prepend cannot fail, checked by caller */
hdr = (struct virtio_net_hdr *)
@ -662,8 +660,7 @@ virtqueue_enqueue_xmit_packed_fast(struct virtnet_tx *txvq,
if (++vq->vq_avail_idx >= vq->vq_nentries) {
vq->vq_avail_idx -= vq->vq_nentries;
vq->avail_wrap_counter ^= 1;
vq->avail_used_flags ^=
vq->cached_flags ^=
VRING_DESC_F_AVAIL(1) | VRING_DESC_F_USED(1);
}
@ -705,7 +702,7 @@ virtqueue_enqueue_xmit_packed(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
head_dp = &vq->ring_packed.desc_packed[idx];
head_flags = cookie->next ? VRING_DESC_F_NEXT : 0;
head_flags |= vq->avail_used_flags;
head_flags |= vq->cached_flags;
if (can_push) {
/* prepend cannot fail, checked by caller */
@ -730,10 +727,8 @@ virtqueue_enqueue_xmit_packed(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
idx++;
if (idx >= vq->vq_nentries) {
idx -= vq->vq_nentries;
vq->avail_wrap_counter ^= 1;
vq->avail_used_flags =
VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
VRING_DESC_F_USED(!vq->avail_wrap_counter);
vq->cached_flags ^=
VRING_DESC_F_AVAIL(1) | VRING_DESC_F_USED(1);
}
}
@ -746,17 +741,15 @@ virtqueue_enqueue_xmit_packed(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
start_dp[idx].len = cookie->data_len;
if (likely(idx != head_idx)) {
flags = cookie->next ? VRING_DESC_F_NEXT : 0;
flags |= vq->avail_used_flags;
flags |= vq->cached_flags;
start_dp[idx].flags = flags;
}
prev = idx;
idx++;
if (idx >= vq->vq_nentries) {
idx -= vq->vq_nentries;
vq->avail_wrap_counter ^= 1;
vq->avail_used_flags =
VRING_DESC_F_AVAIL(vq->avail_wrap_counter) |
VRING_DESC_F_USED(!vq->avail_wrap_counter);
vq->cached_flags ^=
VRING_DESC_F_AVAIL(1) | VRING_DESC_F_USED(1);
}
} while ((cookie = cookie->next) != NULL);

8
drivers/net/virtio/virtqueue.h
View File

@ -193,10 +193,10 @@ struct virtqueue {
struct virtio_hw *hw; /**< virtio_hw structure pointer. */
struct vring vq_ring; /**< vring keeping desc, used and avail */
struct vring_packed ring_packed; /**< vring keeping descs */
bool avail_wrap_counter;
bool used_wrap_counter;
uint16_t cached_flags; /**< cached flags for descs */
uint16_t event_flags_shadow;
uint16_t avail_used_flags;
/**
* Last consumed descriptor in the used table,
* trails vq_ring.used->idx.
@ -478,9 +478,9 @@ virtqueue_notify(struct virtqueue *vq)
if (vtpci_packed_queue((vq)->hw)) { \
PMD_INIT_LOG(DEBUG, \
"VQ: - size=%d; free=%d; used_cons_idx=%d; avail_idx=%d;" \
"VQ: - avail_wrap_counter=%d; used_wrap_counter=%d", \
" cached_flags=0x%x; used_wrap_counter=%d", \
(vq)->vq_nentries, (vq)->vq_free_cnt, (vq)->vq_used_cons_idx, \
(vq)->vq_avail_idx, (vq)->avail_wrap_counter, \
(vq)->vq_avail_idx, (vq)->cached_flags, \
(vq)->used_wrap_counter); \
break; \
} \