Re: [PATCH net-next] net: hns: optimize XGE capability by reducing cpu usage

["Yankejian (Hackim Yim)" <yankejian@huawei.com>]

On 2015/12/7 16:58, Du, Fan wrote:
>
>
> 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?
>

it is almost the same as 82599.

>> Signed-off-by: yankejian <yankejian@huawei.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;
>>
>
> .
>