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Message-ID: <56654A31.4080607@intel.com>
Date: Mon, 07 Dec 2015 16:58:25 +0800
From: "Du, Fan" <fan.du@...el.com>
To: yankejian <yankejian@...wei.com>, davem@...emloft.net,
lisheng011@...wei.com, lipeng321@...wei.com,
salil.mehta@...wei.com, huangdaode@...ilicon.com,
xuwei5@...ilicon.com, liguozhu@...wei.com
CC: haifeng.wei@...wei.com, yisen.zhuang@...wei.com,
linuxarm@...wei.com, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next] net: hns: optimize XGE capability by reducing
cpu usage
On 2015/12/5 15:32, yankejian wrote:
> here is the patch raising the performance of XGE by:
> 1)changes the way page management method for enet momery, and
> 2)reduces the count of rmb, and
> 3)adds Memory prefetching
Any numbers on how much it boost performance?
> Signed-off-by: yankejian <yankejian@...wei.com>
> ---
> drivers/net/ethernet/hisilicon/hns/hnae.h | 5 +-
> drivers/net/ethernet/hisilicon/hns/hns_ae_adapt.c | 1 -
> drivers/net/ethernet/hisilicon/hns/hns_enet.c | 79 +++++++++++++++--------
> 3 files changed, 55 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/net/ethernet/hisilicon/hns/hnae.h b/drivers/net/ethernet/hisilicon/hns/hnae.h
> index d1f3316..6ca94dc 100644
> --- a/drivers/net/ethernet/hisilicon/hns/hnae.h
> +++ b/drivers/net/ethernet/hisilicon/hns/hnae.h
> @@ -341,7 +341,8 @@ struct hnae_queue {
> void __iomem *io_base;
> phys_addr_t phy_base;
> struct hnae_ae_dev *dev; /* the device who use this queue */
> - struct hnae_ring rx_ring, tx_ring;
> + struct hnae_ring rx_ring ____cacheline_internodealigned_in_smp;
> + struct hnae_ring tx_ring ____cacheline_internodealigned_in_smp;
> struct hnae_handle *handle;
> };
>
> @@ -597,11 +598,9 @@ static inline void hnae_replace_buffer(struct hnae_ring *ring, int i,
> struct hnae_desc_cb *res_cb)
> {
> struct hnae_buf_ops *bops = ring->q->handle->bops;
> - struct hnae_desc_cb tmp_cb = ring->desc_cb[i];
>
> bops->unmap_buffer(ring, &ring->desc_cb[i]);
> ring->desc_cb[i] = *res_cb;
> - *res_cb = tmp_cb;
> ring->desc[i].addr = (__le64)ring->desc_cb[i].dma;
> ring->desc[i].rx.ipoff_bnum_pid_flag = 0;
> }
> diff --git a/drivers/net/ethernet/hisilicon/hns/hns_ae_adapt.c b/drivers/net/ethernet/hisilicon/hns/hns_ae_adapt.c
> index 77c6edb..522b264 100644
> --- a/drivers/net/ethernet/hisilicon/hns/hns_ae_adapt.c
> +++ b/drivers/net/ethernet/hisilicon/hns/hns_ae_adapt.c
> @@ -341,7 +341,6 @@ void hns_ae_toggle_ring_irq(struct hnae_ring *ring, u32 mask)
> else
> flag = RCB_INT_FLAG_RX;
>
> - hns_rcb_int_clr_hw(ring->q, flag);
> hns_rcb_int_ctrl_hw(ring->q, flag, mask);
> }
>
> diff --git a/drivers/net/ethernet/hisilicon/hns/hns_enet.c b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
> index cad2663..e2be510 100644
> --- a/drivers/net/ethernet/hisilicon/hns/hns_enet.c
> +++ b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
> @@ -33,6 +33,7 @@
>
> #define RCB_IRQ_NOT_INITED 0
> #define RCB_IRQ_INITED 1
> +#define HNS_BUFFER_SIZE_2048 2048
>
> #define BD_MAX_SEND_SIZE 8191
> #define SKB_TMP_LEN(SKB) \
> @@ -491,13 +492,51 @@ static unsigned int hns_nic_get_headlen(unsigned char *data, u32 flag,
> return max_size;
> }
>
> -static void
> -hns_nic_reuse_page(struct hnae_desc_cb *desc_cb, int tsize, int last_offset)
> +static void hns_nic_reuse_page(struct sk_buff *skb, int i,
> + struct hnae_ring *ring, int pull_len,
> + struct hnae_desc_cb *desc_cb)
> {
> + struct hnae_desc *desc;
> + int truesize, size;
> + int last_offset = 0;
> +
> + desc = &ring->desc[ring->next_to_clean];
> + size = le16_to_cpu(desc->rx.size);
> +
> +#if (PAGE_SIZE < 8192)
> + if (hnae_buf_size(ring) == HNS_BUFFER_SIZE_2048) {
> + truesize = hnae_buf_size(ring);
> + } else {
> + truesize = ALIGN(size, L1_CACHE_BYTES);
> + last_offset = hnae_page_size(ring) - hnae_buf_size(ring);
> + }
> +
> +#else
> + truesize = ALIGN(size, L1_CACHE_BYTES);
> + last_offset = hnae_page_size(ring) - hnae_buf_size(ring);
> +#endif
> +
> + skb_add_rx_frag(skb, i, desc_cb->priv, desc_cb->page_offset + pull_len,
> + size - pull_len, truesize - pull_len);
> +
> /* avoid re-using remote pages,flag default unreuse */
> if (likely(page_to_nid(desc_cb->priv) == numa_node_id())) {
> +#if (PAGE_SIZE < 8192)
> + if (hnae_buf_size(ring) == HNS_BUFFER_SIZE_2048) {
> + /* if we are only owner of page we can reuse it */
> + if (likely(page_count(desc_cb->priv) == 1)) {
> + /* flip page offset to other buffer */
> + desc_cb->page_offset ^= truesize;
> +
> + desc_cb->reuse_flag = 1;
> + /* bump ref count on page before it is given*/
> + get_page(desc_cb->priv);
> + }
> + return;
> + }
> +#endif
> /* move offset up to the next cache line */
> - desc_cb->page_offset += tsize;
> + desc_cb->page_offset += truesize;
>
> if (desc_cb->page_offset <= last_offset) {
> desc_cb->reuse_flag = 1;
> @@ -529,11 +568,10 @@ static int hns_nic_poll_rx_skb(struct hns_nic_ring_data *ring_data,
> struct hnae_desc *desc;
> struct hnae_desc_cb *desc_cb;
> unsigned char *va;
> - int bnum, length, size, i, truesize, last_offset;
> + int bnum, length, i;
> int pull_len;
> u32 bnum_flag;
>
> - last_offset = hnae_page_size(ring) - hnae_buf_size(ring);
> desc = &ring->desc[ring->next_to_clean];
> desc_cb = &ring->desc_cb[ring->next_to_clean];
>
> @@ -555,17 +593,12 @@ static int hns_nic_poll_rx_skb(struct hns_nic_ring_data *ring_data,
> return -ENOMEM;
> }
>
> + prefetchw(skb->data);
> length = le16_to_cpu(desc->rx.pkt_len);
> bnum_flag = le32_to_cpu(desc->rx.ipoff_bnum_pid_flag);
> priv->ops.get_rxd_bnum(bnum_flag, &bnum);
> *out_bnum = bnum;
>
> - /* we will be copying header into skb->data in
> - * pskb_may_pull so it is in our interest to prefetch
> - * it now to avoid a possible cache miss
> - */
> - prefetchw(skb->data);
> -
> if (length <= HNS_RX_HEAD_SIZE) {
> memcpy(__skb_put(skb, length), va, ALIGN(length, sizeof(long)));
>
> @@ -588,13 +621,7 @@ static int hns_nic_poll_rx_skb(struct hns_nic_ring_data *ring_data,
> memcpy(__skb_put(skb, pull_len), va,
> ALIGN(pull_len, sizeof(long)));
>
> - size = le16_to_cpu(desc->rx.size);
> - truesize = ALIGN(size, L1_CACHE_BYTES);
> - skb_add_rx_frag(skb, 0, desc_cb->priv,
> - desc_cb->page_offset + pull_len,
> - size - pull_len, truesize - pull_len);
> -
> - hns_nic_reuse_page(desc_cb, truesize, last_offset);
> + hns_nic_reuse_page(skb, 0, ring, pull_len, desc_cb);
> ring_ptr_move_fw(ring, next_to_clean);
>
> if (unlikely(bnum >= (int)MAX_SKB_FRAGS)) { /* check err*/
> @@ -604,13 +631,8 @@ static int hns_nic_poll_rx_skb(struct hns_nic_ring_data *ring_data,
> for (i = 1; i < bnum; i++) {
> desc = &ring->desc[ring->next_to_clean];
> desc_cb = &ring->desc_cb[ring->next_to_clean];
> - size = le16_to_cpu(desc->rx.size);
> - truesize = ALIGN(size, L1_CACHE_BYTES);
> - skb_add_rx_frag(skb, i, desc_cb->priv,
> - desc_cb->page_offset,
> - size, truesize);
>
> - hns_nic_reuse_page(desc_cb, truesize, last_offset);
> + hns_nic_reuse_page(skb, i, ring, 0, desc_cb);
> ring_ptr_move_fw(ring, next_to_clean);
> }
> }
> @@ -750,9 +772,10 @@ recv:
> /* make all data has been write before submit */
> if (recv_pkts < budget) {
> ex_num = readl_relaxed(ring->io_base + RCB_REG_FBDNUM);
> - rmb(); /*complete read rx ring bd number*/
> +
> if (ex_num > clean_count) {
> num += ex_num - clean_count;
> + rmb(); /*complete read rx ring bd number*/
> goto recv;
> }
> }
> @@ -849,8 +872,11 @@ static int hns_nic_tx_poll_one(struct hns_nic_ring_data *ring_data,
>
> bytes = 0;
> pkts = 0;
> - while (head != ring->next_to_clean)
> + while (head != ring->next_to_clean) {
> hns_nic_reclaim_one_desc(ring, &bytes, &pkts);
> + /* issue prefetch for next Tx descriptor */
> + prefetch(&ring->desc_cb[ring->next_to_clean]);
> + }
>
> NETIF_TX_UNLOCK(ndev);
>
> @@ -926,6 +952,7 @@ static int hns_nic_common_poll(struct napi_struct *napi, int budget)
> ring_data->ring, 0);
>
> ring_data->fini_process(ring_data);
> + return 0;
> }
>
> return clean_complete;
>
--
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