[dpdk-dev] [PATCH v3 1/1] net/mlx5: add hardware TSO support

Nélio Laranjeiro nelio.laranjeiro at 6wind.com
Thu Mar 2 10:15:12 CET 2017


On Thu, Mar 02, 2017 at 11:01:31AM +0200, Shahaf Shuler wrote:
> Implement support for hardware TSO.
> 
> Signed-off-by: Shahaf Shuler <shahafs at mellanox.com>
> ---
> on v3:
>  * fix alignment issues
>  * for warn log
> on v2:
>  * Instead of exposing capability, TSO checks on data path.
>  * PMD specific parameter to enable TSO.
>  * different implementaion for the data path.
>    Performance impact ~0.1-0.2Mpps
> ---
>  doc/guides/nics/features/mlx5.ini |   1 +
>  doc/guides/nics/mlx5.rst          |  12 ++++
>  drivers/net/mlx5/mlx5.c           |  18 ++++++
>  drivers/net/mlx5/mlx5.h           |   2 +
>  drivers/net/mlx5/mlx5_defs.h      |   3 +
>  drivers/net/mlx5/mlx5_ethdev.c    |   2 +
>  drivers/net/mlx5/mlx5_rxtx.c      | 120 +++++++++++++++++++++++++++++++++-----
>  drivers/net/mlx5/mlx5_rxtx.h      |   2 +
>  drivers/net/mlx5/mlx5_txq.c       |  13 +++++
>  9 files changed, 157 insertions(+), 16 deletions(-)
> 
> diff --git a/doc/guides/nics/features/mlx5.ini b/doc/guides/nics/features/mlx5.ini
> index f20d214..6e42150 100644
> --- a/doc/guides/nics/features/mlx5.ini
> +++ b/doc/guides/nics/features/mlx5.ini
> @@ -19,6 +19,7 @@ RSS hash             = Y
>  RSS key update       = Y
>  RSS reta update      = Y
>  SR-IOV               = Y
> +TSO                  = Y
>  VLAN filter          = Y
>  Flow director        = Y
>  Flow API             = Y
> diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
> index 09922a0..8651456 100644
> --- a/doc/guides/nics/mlx5.rst
> +++ b/doc/guides/nics/mlx5.rst
> @@ -90,6 +90,7 @@ Features
>  - Secondary process TX is supported.
>  - KVM and VMware ESX SR-IOV modes are supported.
>  - RSS hash result is supported.
> +- Hardware TSO.
>  
>  Limitations
>  -----------
> @@ -186,9 +187,20 @@ Run-time configuration
>    save PCI bandwidth and improve performance at the cost of a slightly
>    higher CPU usage.
>  
> +  This option cannot be used in conjunction with ``tso`` below. When ``tso``
> +  is set, ``txq_mpw_en`` is disabled.
> +
>    It is currently only supported on the ConnectX-4 Lx and ConnectX-5
>    families of adapters. Enabled by default.
>  
> +- ``tso`` parameter [int]
> +
> +  A nonzero value enables hardware TSO.
> +  When hardware TSO is enabled, packets marked with TCP segmentation
> +  offload will be divided into segments by the hardware.
> +
> +  Disabled by default.
> +
>  Prerequisites
>  -------------
>  
> diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c
> index d4bd469..03ed3b3 100644
> --- a/drivers/net/mlx5/mlx5.c
> +++ b/drivers/net/mlx5/mlx5.c
> @@ -84,6 +84,9 @@
>  /* Device parameter to enable multi-packet send WQEs. */
>  #define MLX5_TXQ_MPW_EN "txq_mpw_en"
>  
> +/* Device parameter to enable hardware TSO offload. */
> +#define MLX5_TSO "tso"
> +
>  /**
>   * Retrieve integer value from environment variable.
>   *
> @@ -290,6 +293,8 @@
>  		priv->txqs_inline = tmp;
>  	} else if (strcmp(MLX5_TXQ_MPW_EN, key) == 0) {
>  		priv->mps &= !!tmp; /* Enable MPW only if HW supports */
> +	} else if (strcmp(MLX5_TSO, key) == 0) {
> +		priv->tso = !!tmp;
>  	} else {
>  		WARN("%s: unknown parameter", key);
>  		return -EINVAL;
> @@ -316,6 +321,7 @@
>  		MLX5_TXQ_INLINE,
>  		MLX5_TXQS_MIN_INLINE,
>  		MLX5_TXQ_MPW_EN,
> +		MLX5_TSO,
>  		NULL,
>  	};
>  	struct rte_kvargs *kvlist;
> @@ -479,6 +485,7 @@
>  			IBV_EXP_DEVICE_ATTR_RX_HASH |
>  			IBV_EXP_DEVICE_ATTR_VLAN_OFFLOADS |
>  			IBV_EXP_DEVICE_ATTR_RX_PAD_END_ALIGN |
> +			IBV_EXP_DEVICE_ATTR_TSO_CAPS |
>  			0;
>  
>  		DEBUG("using port %u (%08" PRIx32 ")", port, test);
> @@ -580,11 +587,22 @@
>  
>  		priv_get_num_vfs(priv, &num_vfs);
>  		priv->sriov = (num_vfs || sriov);
> +		priv->tso = ((priv->tso) &&
> +			    (exp_device_attr.tso_caps.max_tso > 0) &&
> +			    (exp_device_attr.tso_caps.supported_qpts &
> +			    (1 << IBV_QPT_RAW_ETH)));
> +		if (priv->tso)
> +			priv->max_tso_payload_sz =
> +				exp_device_attr.tso_caps.max_tso;
>  		if (priv->mps && !mps) {
>  			ERROR("multi-packet send not supported on this device"
>  			      " (" MLX5_TXQ_MPW_EN ")");
>  			err = ENOTSUP;
>  			goto port_error;
> +		} else if (priv->mps && priv->tso) {
> +			WARN("multi-packet send not supported in conjunction "
> +			      "with TSO. MPS disabled");
> +			priv->mps = 0;
>  		}
>  		/* Allocate and register default RSS hash keys. */
>  		priv->rss_conf = rte_calloc(__func__, hash_rxq_init_n,
> diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
> index 2b4345a..d2bb835 100644
> --- a/drivers/net/mlx5/mlx5.h
> +++ b/drivers/net/mlx5/mlx5.h
> @@ -126,6 +126,8 @@ struct priv {
>  	unsigned int mps:1; /* Whether multi-packet send is supported. */
>  	unsigned int cqe_comp:1; /* Whether CQE compression is enabled. */
>  	unsigned int pending_alarm:1; /* An alarm is pending. */
> +	unsigned int tso:1; /* Whether TSO is supported. */
> +	unsigned int max_tso_payload_sz; /* Maximum TCP payload for TSO. */
>  	unsigned int txq_inline; /* Maximum packet size for inlining. */
>  	unsigned int txqs_inline; /* Queue number threshold for inlining. */
>  	/* RX/TX queues. */
> diff --git a/drivers/net/mlx5/mlx5_defs.h b/drivers/net/mlx5/mlx5_defs.h
> index e91d245..eecb908 100644
> --- a/drivers/net/mlx5/mlx5_defs.h
> +++ b/drivers/net/mlx5/mlx5_defs.h
> @@ -79,4 +79,7 @@
>  /* Maximum number of extended statistics counters. */
>  #define MLX5_MAX_XSTATS 32
>  
> +/* Maximum Packet headers size (L2+L3+L4) for TSO. */
> +#define MLX5_MAX_TSO_HEADER 128
> +
>  #endif /* RTE_PMD_MLX5_DEFS_H_ */
> diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
> index 5677f03..5542193 100644
> --- a/drivers/net/mlx5/mlx5_ethdev.c
> +++ b/drivers/net/mlx5/mlx5_ethdev.c
> @@ -693,6 +693,8 @@ struct priv *
>  			(DEV_TX_OFFLOAD_IPV4_CKSUM |
>  			 DEV_TX_OFFLOAD_UDP_CKSUM |
>  			 DEV_TX_OFFLOAD_TCP_CKSUM);
> +	if (priv->tso)
> +		info->tx_offload_capa |= DEV_TX_OFFLOAD_TCP_TSO;
>  	if (priv_get_ifname(priv, &ifname) == 0)
>  		info->if_index = if_nametoindex(ifname);
>  	/* FIXME: RETA update/query API expects the callee to know the size of
> diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
> index b2b7223..3589aae 100644
> --- a/drivers/net/mlx5/mlx5_rxtx.c
> +++ b/drivers/net/mlx5/mlx5_rxtx.c
> @@ -365,6 +365,7 @@
>  	const unsigned int elts_n = 1 << txq->elts_n;
>  	unsigned int i = 0;
>  	unsigned int j = 0;
> +	unsigned int k = 0;
>  	unsigned int max;
>  	uint16_t max_wqe;
>  	unsigned int comp;
> @@ -392,8 +393,10 @@
>  		uintptr_t addr;
>  		uint64_t naddr;
>  		uint16_t pkt_inline_sz = MLX5_WQE_DWORD_SIZE + 2;
> +		uint16_t tso_header_sz = 0;
>  		uint16_t ehdr;
>  		uint8_t cs_flags = 0;
> +		uint64_t tso = 0;
>  #ifdef MLX5_PMD_SOFT_COUNTERS
>  		uint32_t total_length = 0;
>  #endif
> @@ -465,14 +468,71 @@
>  			length -= pkt_inline_sz;
>  			addr += pkt_inline_sz;
>  		}
> +		if (txq->tso_en) {
> +			tso = buf->ol_flags & PKT_TX_TCP_SEG;
> +			if (tso) {
> +				uintptr_t end = (uintptr_t)
> +						(((uintptr_t)txq->wqes) +
> +						(1 << txq->wqe_n) *
> +						MLX5_WQE_SIZE);
> +				unsigned int copy_b;
> +
> +				tso_header_sz = buf->l2_len + buf->l3_len +
> +						buf->l4_len;
> +				if (unlikely(tso_header_sz >
> +					     MLX5_MAX_TSO_HEADER))
> +					break;
> +				copy_b = tso_header_sz - pkt_inline_sz;
> +				/* First seg must contain all headers. */
> +				assert(copy_b <= length);
> +				raw += MLX5_WQE_DWORD_SIZE;
> +				if (copy_b &&
> +				   ((end - (uintptr_t)raw) > copy_b)) {
> +					uint16_t n = (MLX5_WQE_DS(copy_b) -
> +						      1 + 3) / 4;
> +
> +					if (unlikely(max_wqe < n))
> +						break;
> +					max_wqe -= n;
> +					rte_memcpy((void *)raw,
> +						   (void *)addr, copy_b);
> +					addr += copy_b;
> +					length -= copy_b;
> +					pkt_inline_sz += copy_b;
> +					/*
> +					 * Another DWORD will be added
> +					 * in the inline part.
> +					 */
> +					raw += MLX5_WQE_DS(copy_b) *
> +					       MLX5_WQE_DWORD_SIZE -
> +					       MLX5_WQE_DWORD_SIZE;
> +				} else {
> +					/* NOP WQE. */
> +					wqe->ctrl = (rte_v128u32_t){
> +						     htonl(txq->wqe_ci << 8),
> +						     htonl(txq->qp_num_8s | 1),
> +						     0,
> +						     0,
> +					};
> +					ds = 1;
> +					total_length = 0;
> +					pkts--;
> +					pkts_n++;
> +					elts_head = (elts_head - 1) &
> +						    (elts_n - 1);
> +					k++;
> +					goto next_wqe;
> +				}
> +			}
> +		}
>  		/* Inline if enough room. */
> -		if (txq->max_inline) {
> +		if (txq->inline_en || tso) {
>  			uintptr_t end = (uintptr_t)
>  				(((uintptr_t)txq->wqes) +
>  				 (1 << txq->wqe_n) * MLX5_WQE_SIZE);
>  			unsigned int max_inline = txq->max_inline *
>  						  RTE_CACHE_LINE_SIZE -
> -						  MLX5_WQE_DWORD_SIZE;
> +						  (pkt_inline_sz - 2);
>  			uintptr_t addr_end = (addr + max_inline) &
>  					     ~(RTE_CACHE_LINE_SIZE - 1);
>  			unsigned int copy_b = (addr_end > addr) ?
> @@ -491,6 +551,18 @@
>  				if (unlikely(max_wqe < n))
>  					break;
>  				max_wqe -= n;
> +				if (tso) {
> +					uint32_t inl =
> +						htonl(copy_b | MLX5_INLINE_SEG);
> +
> +					pkt_inline_sz =
> +						MLX5_WQE_DS(tso_header_sz) *
> +						MLX5_WQE_DWORD_SIZE;
> +					rte_memcpy((void *)raw,
> +						   (void *)&inl, sizeof(inl));
> +					raw += sizeof(inl);
> +					pkt_inline_sz += sizeof(inl);
> +				}
>  				rte_memcpy((void *)raw, (void *)addr, copy_b);
>  				addr += copy_b;
>  				length -= copy_b;
> @@ -591,18 +663,34 @@
>  next_pkt:
>  		++i;
>  		/* Initialize known and common part of the WQE structure. */
> -		wqe->ctrl = (rte_v128u32_t){
> -			htonl((txq->wqe_ci << 8) | MLX5_OPCODE_SEND),
> -			htonl(txq->qp_num_8s | ds),
> -			0,
> -			0,
> -		};
> -		wqe->eseg = (rte_v128u32_t){
> -			0,
> -			cs_flags,
> -			0,
> -			(ehdr << 16) | htons(pkt_inline_sz),
> -		};
> +		if (tso) {
> +			wqe->ctrl = (rte_v128u32_t){
> +				htonl((txq->wqe_ci << 8) | MLX5_OPCODE_TSO),
> +				htonl(txq->qp_num_8s | ds),
> +				0,
> +				0,
> +			};
> +			wqe->eseg = (rte_v128u32_t){
> +				0,
> +				cs_flags | (htons(buf->tso_segsz) << 16),
> +				0,
> +				(ehdr << 16) | htons(tso_header_sz),
> +			};
> +		} else {
> +			wqe->ctrl = (rte_v128u32_t){
> +				htonl((txq->wqe_ci << 8) | MLX5_OPCODE_SEND),
> +				htonl(txq->qp_num_8s | ds),
> +				0,
> +				0,
> +			};
> +			wqe->eseg = (rte_v128u32_t){
> +				0,
> +				cs_flags,
> +				0,
> +				(ehdr << 16) | htons(pkt_inline_sz),
> +			};
> +		}
> +next_wqe:
>  		txq->wqe_ci += (ds + 3) / 4;
>  #ifdef MLX5_PMD_SOFT_COUNTERS
>  		/* Increment sent bytes counter. */
> @@ -610,10 +698,10 @@
>  #endif
>  	} while (pkts_n);
>  	/* Take a shortcut if nothing must be sent. */
> -	if (unlikely(i == 0))
> +	if (unlikely((i + k) == 0))
>  		return 0;
>  	/* Check whether completion threshold has been reached. */
> -	comp = txq->elts_comp + i + j;
> +	comp = txq->elts_comp + i + j + k;
>  	if (comp >= MLX5_TX_COMP_THRESH) {
>  		volatile struct mlx5_wqe_ctrl *w =
>  			(volatile struct mlx5_wqe_ctrl *)wqe;
> diff --git a/drivers/net/mlx5/mlx5_rxtx.h b/drivers/net/mlx5/mlx5_rxtx.h
> index 41a34d7..6b328cf 100644
> --- a/drivers/net/mlx5/mlx5_rxtx.h
> +++ b/drivers/net/mlx5/mlx5_rxtx.h
> @@ -254,6 +254,8 @@ struct txq {
>  	uint16_t cqe_n:4; /* Number of CQ elements (in log2). */
>  	uint16_t wqe_n:4; /* Number of of WQ elements (in log2). */
>  	uint16_t max_inline; /* Multiple of RTE_CACHE_LINE_SIZE to inline. */
> +	uint16_t inline_en:1; /* When set inline is enabled. */
> +	uint16_t tso_en:1; /* When set hardware TSO is enabled. */
>  	uint32_t qp_num_8s; /* QP number shifted by 8. */
>  	volatile struct mlx5_cqe (*cqes)[]; /* Completion queue. */
>  	volatile void *wqes; /* Work queue (use volatile to write into). */
> diff --git a/drivers/net/mlx5/mlx5_txq.c b/drivers/net/mlx5/mlx5_txq.c
> index 949035b..995b763 100644
> --- a/drivers/net/mlx5/mlx5_txq.c
> +++ b/drivers/net/mlx5/mlx5_txq.c
> @@ -342,6 +342,19 @@
>  			 RTE_CACHE_LINE_SIZE);
>  		attr.init.cap.max_inline_data =
>  			tmpl.txq.max_inline * RTE_CACHE_LINE_SIZE;
> +		tmpl.txq.inline_en = 1;
> +	}
> +	if (priv->tso) {
> +		uint16_t max_tso_inline = ((MLX5_MAX_TSO_HEADER +
> +					   (RTE_CACHE_LINE_SIZE - 1)) /
> +					    RTE_CACHE_LINE_SIZE);
> +
> +		attr.init.max_tso_header =
> +			max_tso_inline * RTE_CACHE_LINE_SIZE;
> +		attr.init.comp_mask |= IBV_EXP_QP_INIT_ATTR_MAX_TSO_HEADER;
> +		tmpl.txq.max_inline = RTE_MAX(tmpl.txq.max_inline,
> +					      max_tso_inline);
> +		tmpl.txq.tso_en = 1;
>  	}
>  	tmpl.qp = ibv_exp_create_qp(priv->ctx, &attr.init);
>  	if (tmpl.qp == NULL) {
> -- 
> 1.8.3.1
> 

Acked-by: Nelio Laranjeiro <nelio.laranjeiro at 6wind.com>

-- 
Nélio Laranjeiro
6WIND


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