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net: hns3: use bounce buffer when rx page can not be reused

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Currently rx page will be reused to receive future packet when
the stack releases the previous skb quickly. If the old page
can not be reused, a new page will be allocated and mapped,
which comsumes a lot of cpu when IOMMU is in the strict mode,
especially when the application and irq/NAPI happens to run on
the same cpu.

So allocate a new frag to memcpy the data to avoid the costly
IOMMU unmapping/mapping operation, and add "frag_alloc_err"
and "frag_alloc" stats in "ethtool -S ethX" cmd.

The throughput improves above 50% when running single thread of
iperf using TCP when IOMMU is in strict mode and iperf shares the
same cpu with irq/NAPI(rx_copybreak = 2048 and mtu = 1500).

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yunsheng Lin 2021-06-16 14:36:17 +08:00 committed by David S. Miller
parent fa7711b888
commit 99f6b5fb5f
4 changed files with 41 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
View File

@ -450,6 +450,7 @@ static const struct hns3_dbg_item rx_queue_info_items[] = {
{ "HEAD", 2 },
{ "FBDNUM", 2 },
{ "PKTNUM", 2 },
{ "COPYBREAK", 2 },
{ "RING_EN", 2 },
{ "RX_RING_EN", 2 },
{ "BASE_ADDR", 10 },
@ -481,6 +482,7 @@ static void hns3_dump_rx_queue_info(struct hns3_enet_ring *ring,
sprintf(result[j++], "%6u", readl_relaxed(ring->tqp->io_base +
HNS3_RING_RX_RING_PKTNUM_RECORD_REG));
sprintf(result[j++], "%9u", ring->rx_copybreak);
sprintf(result[j++], "%7s", readl_relaxed(ring->tqp->io_base +
HNS3_RING_EN_REG) ? "on" : "off");

23
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
View File

@ -3552,6 +3552,28 @@ static void hns3_nic_reuse_page(struct sk_buff *skb, int i,
hns3_page_size(ring)) {
desc_cb->page_offset += truesize;
desc_cb->reuse_flag = 1;
} else if (frag_size <= ring->rx_copybreak) {
void *frag = napi_alloc_frag(frag_size);
if (unlikely(!frag)) {
u64_stats_update_begin(&ring->syncp);
ring->stats.frag_alloc_err++;
u64_stats_update_end(&ring->syncp);
hns3_rl_err(ring_to_netdev(ring),
"failed to allocate rx frag\n");
goto out;
}
desc_cb->reuse_flag = 1;
memcpy(frag, desc_cb->buf + frag_offset, frag_size);
skb_add_rx_frag(skb, i, virt_to_page(frag),
offset_in_page(frag), frag_size, frag_size);
u64_stats_update_begin(&ring->syncp);
ring->stats.frag_alloc++;
u64_stats_update_end(&ring->syncp);
return;
}
out:
@ -4620,6 +4642,7 @@ static void hns3_ring_get_cfg(struct hnae3_queue *q, struct hns3_nic_priv *priv,
ring = &priv->ring[q->tqp_index + queue_num];
desc_num = priv->ae_handle->kinfo.num_rx_desc;
ring->queue_index = q->tqp_index;
ring->rx_copybreak = priv->rx_copybreak;
}
hnae3_set_bit(ring->flag, HNAE3_RING_TYPE_B, ring_type);

4
drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
View File

@ -427,6 +427,8 @@ struct ring_stats {
u64 csum_complete;
u64 rx_multicast;
u64 non_reuse_pg;
u64 frag_alloc_err;
u64 frag_alloc;
};
__le16 csum;
};
@ -478,6 +480,7 @@ struct hns3_enet_ring {
/* for Rx ring */
struct {
u32 pull_len; /* memcpy len for current rx packet */
u32 rx_copybreak;
u32 frag_num;
/* first buffer address for current packet */
unsigned char *va;
@ -569,6 +572,7 @@ struct hns3_nic_priv {
struct hns3_enet_coalesce tx_coal;
struct hns3_enet_coalesce rx_coal;
u32 tx_copybreak;
u32 rx_copybreak;
};
union l3_hdr_info {

12
drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
View File

@ -71,6 +71,8 @@ static const struct hns3_stats hns3_rxq_stats[] = {
HNS3_TQP_STAT("csum_complete", csum_complete),
HNS3_TQP_STAT("multicast", rx_multicast),
HNS3_TQP_STAT("non_reuse_pg", non_reuse_pg),
HNS3_TQP_STAT("frag_alloc_err", frag_alloc_err),
HNS3_TQP_STAT("frag_alloc", frag_alloc),
};
#define HNS3_PRIV_FLAGS_LEN ARRAY_SIZE(hns3_priv_flags)
@ -1610,6 +1612,9 @@ static int hns3_get_tunable(struct net_device *netdev,
/* all the tx rings have the same tx_copybreak */
*(u32 *)data = priv->tx_copybreak;
break;
case ETHTOOL_RX_COPYBREAK:
*(u32 *)data = priv->rx_copybreak;
break;
default:
ret = -EOPNOTSUPP;
break;
@ -1633,6 +1638,13 @@ static int hns3_set_tunable(struct net_device *netdev,
for (i = 0; i < h->kinfo.num_tqps; i++)
priv->ring[i].tx_copybreak = priv->tx_copybreak;
break;
case ETHTOOL_RX_COPYBREAK:
priv->rx_copybreak = *(u32 *)data;
for (i = h->kinfo.num_tqps; i < h->kinfo.num_tqps * 2; i++)
priv->ring[i].rx_copybreak = priv->rx_copybreak;
break;
default:
ret = -EOPNOTSUPP;