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drivers/virtio-net: Add support to offload small IOBs

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TCP receive tested with different IOB_BUFSIZE:
|             | 256B vs 1534B | 512B vs 1534B | 768B vs 1534B |
| :---------: | :-----------: | :-----------: | :-----------: |
|     Non-SMP |     ~85%      |     ~93%      |     ~96%      |
|  armv8a-SMP |     ~66%      |     ~84%      |     ~92%      |
| rv32/64-SMP |     ~52%      |     ~72%      |     ~83%      |

It seems we still get performance penalty on smaller IOBs, and may be
affected more under SMP mode. It may be caused by critical sections in
IOB operations.

Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
This commit is contained in:
Zhe Weng 2023-07-04 19:01:00 +08:00 committed by Masayuki Ishikawa
parent 318d136320
commit 5597b8a9e2
1 changed files with 55 additions and 17 deletions
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72
drivers/virtio/virtio-net.c
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@ -43,7 +43,7 @@
#define VIRTIO_NET_HDRSIZE (sizeof(struct virtio_net_hdr_s))
#define VIRTIO_NET_LLHDRSIZE (sizeof(struct virtio_net_llhdr_s))
#define VIRTIO_NET_BUFSIZE (MAX_NETDEV_PKTSIZE + CONFIG_NET_GUARDSIZE)
#define VIRTIO_NET_BUFSIZE (CONFIG_NET_ETH_PKTSIZE + CONFIG_NET_GUARDSIZE)
/* Virtio net virtqueue index and number */
@ -51,6 +51,11 @@
#define VIRTIO_NET_TX 1
#define VIRTIO_NET_NUM 2
#define VIRTIO_NET_MAX_PKT_SIZE \
((CONFIG_NET_LL_GUARDSIZE - ETH_HDRLEN) + VIRTIO_NET_BUFSIZE)
#define VIRTIO_NET_MAX_NIOB \
((VIRTIO_NET_MAX_PKT_SIZE + CONFIG_IOB_BUFSIZE - 1) / CONFIG_IOB_BUFSIZE)
/****************************************************************************
* Private Types
****************************************************************************/
@ -168,8 +173,10 @@ static void virtio_net_rxfill(FAR struct netdev_lowerhalf_s *dev)
FAR struct virtio_net_priv_s *priv = (FAR struct virtio_net_priv_s *)dev;
FAR struct virtqueue *vq = priv->vdev->vrings_info[VIRTIO_NET_RX].vq;
FAR struct virtio_net_llhdr_s *hdr;
FAR struct virtqueue_buf vb;
struct virtqueue_buf vb[VIRTIO_NET_MAX_NIOB];
struct iovec iov[VIRTIO_NET_MAX_NIOB];
FAR netpkt_t *pkt;
int iov_cnt;
int i;
for (i = 0; i < priv->bufnum; i++)
@ -183,21 +190,40 @@ static void virtio_net_rxfill(FAR struct netdev_lowerhalf_s *dev)
break;
}
/* Preserve data length */
if (netpkt_setdatalen(dev, pkt, VIRTIO_NET_BUFSIZE) <
VIRTIO_NET_BUFSIZE)
{
vrtwarn("No enough buffer to prepare RX buffer, i=%d\n", i);
netpkt_free(dev, pkt, NETPKT_RX);
break;
}
/* Convert netpkt to virtqueue_buf */
iov_cnt = netpkt_to_iov(dev, pkt, iov, VIRTIO_NET_MAX_NIOB);
for (i = 0; i < iov_cnt; i++)
{
vb[i].buf = iov[i].iov_base;
vb[i].len = iov[i].iov_len;
}
/* Alloc cookie and net header from transport layer */
hdr = (FAR struct virtio_net_llhdr_s *)
(netpkt_getdata(dev, pkt) - VIRTIO_NET_LLHDRSIZE);
((FAR uint8_t *)vb[0].buf - VIRTIO_NET_LLHDRSIZE);
DEBUGASSERT((FAR uint8_t *)hdr >= netpkt_getbase(pkt));
memset(&hdr->vhdr, 0, sizeof(hdr->vhdr));
hdr->pkt = pkt;
/* Buffer 0, the virtio net header */
vb.buf = &hdr->vhdr;
vb.len = VIRTIO_NET_HDRSIZE + VIRTIO_NET_BUFSIZE;
vb[0].buf = &hdr->vhdr;
vb[0].len += VIRTIO_NET_HDRSIZE;
vrtinfo("Fill rx, hdr=%p, buf=%p, buflen=%d\n", hdr, vb.buf, vb.len);
virtqueue_add_buffer(vq, &vb, 0, 1, hdr);
vrtinfo("Fill rx, hdr=%p, count=%d\n", hdr, iov_cnt);
virtqueue_add_buffer(vq, vb, 0, iov_cnt, hdr);
}
if (i > 0)
@ -289,33 +315,45 @@ static int virtio_net_send(FAR struct netdev_lowerhalf_s *dev,
FAR struct virtio_net_priv_s *priv = (FAR struct virtio_net_priv_s *)dev;
FAR struct virtqueue *vq = priv->vdev->vrings_info[VIRTIO_NET_TX].vq;
FAR struct virtio_net_llhdr_s *hdr;
struct virtqueue_buf vb;
size_t len;
struct virtqueue_buf vb[VIRTIO_NET_MAX_NIOB];
struct iovec iov[VIRTIO_NET_MAX_NIOB];
int iov_cnt;
int i;
/* Check the send length */
len = netpkt_getdatalen(dev, pkt);
if (len > VIRTIO_NET_BUFSIZE)
if (netpkt_getdatalen(dev, pkt) > VIRTIO_NET_BUFSIZE)
{
vrterr("net send buffer too large\n");
return -EINVAL;
}
/* Convert netpkt to virtqueue_buf */
iov_cnt = netpkt_to_iov(dev, pkt, iov, VIRTIO_NET_MAX_NIOB);
for (i = 0; i < iov_cnt; i++)
{
vb[i].buf = iov[i].iov_base;
vb[i].len = iov[i].iov_len;
}
/* Prepare virtio net header */
hdr = (FAR struct virtio_net_llhdr_s *)
(netpkt_getdata(dev, pkt) - VIRTIO_NET_LLHDRSIZE);
((FAR uint8_t *)vb[0].buf - VIRTIO_NET_LLHDRSIZE);
DEBUGASSERT((FAR uint8_t *)hdr >= netpkt_getbase(pkt));
hdr->pkt = pkt;
memset(&hdr->vhdr, 0, sizeof(hdr->vhdr));
/* Buffer 0 is the virtio net header */
vb.buf = &hdr->vhdr;
vb.len = VIRTIO_NET_HDRSIZE + len;
vb[0].buf = &hdr->vhdr;
vb[0].len += VIRTIO_NET_HDRSIZE;
/* Add buffer to vq and notify the other side */
vrtinfo("Send, hdr=%p, buf=%p, buflen=%d\n", hdr, vb.buf, vb.len);
virtqueue_add_buffer(vq, &vb, 1, 0, hdr);
vrtinfo("Send, hdr=%p, count=%d\n", hdr, iov_cnt);
virtqueue_add_buffer(vq, vb, iov_cnt, 0, hdr);
virtqueue_kick(vq);
/* Try return Netpkt TX buffer to upper-half. */
@ -473,7 +511,7 @@ static int virtio_net_init(FAR struct virtio_net_priv_s *priv,
* 1/4 for the TX netpkts, 1/4 for the RX netpkts.
*/
priv->bufnum = CONFIG_IOB_NBUFFERS / 4;
priv->bufnum = CONFIG_IOB_NBUFFERS / VIRTIO_NET_MAX_NIOB / 4;
#endif
priv->bufnum = MIN(vdev->vrings_info[VIRTIO_NET_RX].info.num_descs,
priv->bufnum);