From: Yunsheng Lin linyunsheng@huawei.com
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 --- drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c | 2 ++ drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 23 ++++++++++++++++++++++ drivers/net/ethernet/hisilicon/hns3/hns3_enet.h | 4 ++++ drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c | 12 +++++++++++ 4 files changed, 41 insertions(+)
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c index a24a75c..34b6cd9 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c @@ -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"); diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c index 98e8a54..51bbf5f 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c @@ -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); diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h index 22ae291..15af3d9 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h @@ -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 { diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c index d785271..82061ab 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c @@ -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; @@ -1634,6 +1639,13 @@ static int hns3_set_tunable(struct net_device *netdev, 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; break;