From 7dfa4b414d4eec8da56e44fb2b4aea3e549b092f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:09 +0300 Subject: [PATCH 01/14] net/mlx4_en: Code cleanups in tx path - Remove unused variable ring->poll_cnt - No need to set some fields if using blueflame - Add missing const's - Use unlikely - Remove unneeded new line - Make some comments more precise - struct mlx4_bf @offset field reduced to unsigned int to save space Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 49 +++++++++++--------- drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 - include/linux/mlx4/device.h | 2 +- 3 files changed, 27 insertions(+), 25 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index 0c501253fdabb..eaf23eb7266a0 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -191,7 +191,6 @@ int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv, ring->prod = 0; ring->cons = 0xffffffff; ring->last_nr_txbb = 1; - ring->poll_cnt = 0; memset(ring->tx_info, 0, ring->size * sizeof(struct mlx4_en_tx_info)); memset(ring->buf, 0, ring->buf_size); @@ -512,7 +511,8 @@ static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv, return ring->buf + index * TXBB_SIZE; } -static int is_inline(int inline_thold, struct sk_buff *skb, void **pfrag) +static bool is_inline(int inline_thold, const struct sk_buff *skb, + void **pfrag) { void *ptr; @@ -535,7 +535,7 @@ static int is_inline(int inline_thold, struct sk_buff *skb, void **pfrag) return 0; } -static int inline_size(struct sk_buff *skb) +static int inline_size(const struct sk_buff *skb) { if (skb->len + CTRL_SIZE + sizeof(struct mlx4_wqe_inline_seg) <= MLX4_INLINE_ALIGN) @@ -546,7 +546,8 @@ static int inline_size(struct sk_buff *skb) sizeof(struct mlx4_wqe_inline_seg), 16); } -static int get_real_size(struct sk_buff *skb, struct net_device *dev, +static int get_real_size(const struct sk_buff *skb, + struct net_device *dev, int *lso_header_size) { struct mlx4_en_priv *priv = netdev_priv(dev); @@ -581,8 +582,10 @@ static int get_real_size(struct sk_buff *skb, struct net_device *dev, return real_size; } -static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc, struct sk_buff *skb, - int real_size, u16 *vlan_tag, int tx_ind, void *fragptr) +static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc, + const struct sk_buff *skb, + int real_size, u16 *vlan_tag, + int tx_ind, void *fragptr) { struct mlx4_wqe_inline_seg *inl = &tx_desc->inl; int spc = MLX4_INLINE_ALIGN - CTRL_SIZE - sizeof *inl; @@ -642,7 +645,8 @@ u16 mlx4_en_select_queue(struct net_device *dev, struct sk_buff *skb, return fallback(dev, skb) % rings_p_up + up * rings_p_up; } -static void mlx4_bf_copy(void __iomem *dst, unsigned long *src, unsigned bytecnt) +static void mlx4_bf_copy(void __iomem *dst, const void *src, + unsigned int bytecnt) { __iowrite64_copy(dst, src, bytecnt / 8); } @@ -736,11 +740,10 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) tx_info->skb = skb; tx_info->nr_txbb = nr_txbb; + data = &tx_desc->data; if (lso_header_size) data = ((void *)&tx_desc->lso + ALIGN(lso_header_size + 4, DS_SIZE)); - else - data = &tx_desc->data; /* valid only for none inline segments */ tx_info->data_offset = (void *)data - (void *)tx_desc; @@ -753,9 +756,9 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) if (is_inline(ring->inline_thold, skb, &fragptr)) { tx_info->inl = 1; } else { - /* Map fragments */ + /* Map fragments if any */ for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) { - struct skb_frag_struct *frag; + const struct skb_frag_struct *frag; dma_addr_t dma; frag = &skb_shinfo(skb)->frags[i]; @@ -772,7 +775,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) --data; } - /* Map linear part */ + /* Map linear part if needed */ if (tx_info->linear) { u32 byte_count = skb_headlen(skb) - lso_header_size; dma_addr_t dma; @@ -795,18 +798,14 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) * For timestamping add flag to skb_shinfo and * set flag for further reference */ - if (ring->hwtstamp_tx_type == HWTSTAMP_TX_ON && - skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) { - skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS; + if (unlikely(ring->hwtstamp_tx_type == HWTSTAMP_TX_ON && + shinfo->tx_flags & SKBTX_HW_TSTAMP)) { + shinfo->tx_flags |= SKBTX_IN_PROGRESS; tx_info->ts_requested = 1; } /* Prepare ctrl segement apart opcode+ownership, which depends on * whether LSO is used */ - tx_desc->ctrl.vlan_tag = cpu_to_be16(vlan_tag); - tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_VLAN * - !!vlan_tx_tag_present(skb); - tx_desc->ctrl.fence_size = (real_size / 16) & 0x3f; tx_desc->ctrl.srcrb_flags = priv->ctrl_flags; if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) { tx_desc->ctrl.srcrb_flags |= cpu_to_be32(MLX4_WQE_CTRL_IP_CSUM | @@ -852,7 +851,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0); tx_info->nr_bytes = max_t(unsigned int, skb->len, ETH_ZLEN); ring->packets++; - } ring->bytes += tx_info->nr_bytes; netdev_tx_sent_queue(ring->tx_queue, tx_info->nr_bytes); @@ -874,7 +872,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) ring->prod += nr_txbb; /* If we used a bounce buffer then copy descriptor back into place */ - if (bounce) + if (unlikely(bounce)) tx_desc = mlx4_en_bounce_to_desc(priv, ring, index, desc_size); skb_tx_timestamp(skb); @@ -894,13 +892,18 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) wmb(); - mlx4_bf_copy(ring->bf.reg + ring->bf.offset, (unsigned long *) &tx_desc->ctrl, - desc_size); + mlx4_bf_copy(ring->bf.reg + ring->bf.offset, &tx_desc->ctrl, + desc_size); wmb(); ring->bf.offset ^= ring->bf.buf_size; } else { + tx_desc->ctrl.vlan_tag = cpu_to_be16(vlan_tag); + tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_VLAN * + !!vlan_tx_tag_present(skb); + tx_desc->ctrl.fence_size = real_size; + /* Ensure new descriptor hits memory * before setting ownership of this descriptor to HW */ diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h index 84c9d5dbfa4f3..e54b653de3d41 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h @@ -263,7 +263,6 @@ struct mlx4_en_tx_ring { u32 buf_size; u32 doorbell_qpn; void *buf; - u16 poll_cnt; struct mlx4_en_tx_info *tx_info; u8 *bounce_buf; u8 queue_index; diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h index b2f8ab9a57c40..37e4404d0227f 100644 --- a/include/linux/mlx4/device.h +++ b/include/linux/mlx4/device.h @@ -583,7 +583,7 @@ struct mlx4_uar { }; struct mlx4_bf { - unsigned long offset; + unsigned int offset; int buf_size; struct mlx4_uar *uar; void __iomem *reg; From 98b1634941e3efb0334f794efc79702839993d86 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:10 +0300 Subject: [PATCH 02/14] net/mlx4_en: Align tx path structures to cache lines Reorganize struct mlx4_en_tx_ring to have: - One cache line containing last_nr_txbb & cons & wake_queue, used by tx completion. - One cache line containing fields dirtied by mlx4_en_xmit() - Following part is read mostly and shared by cpus. Align struct mlx4_en_tx_info to a cache line Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 86 +++++++++++--------- 1 file changed, 46 insertions(+), 40 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h index e54b653de3d41..b7bde95e05fe1 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h @@ -216,13 +216,13 @@ enum cq_type { struct mlx4_en_tx_info { struct sk_buff *skb; - u32 nr_txbb; - u32 nr_bytes; - u8 linear; - u8 data_offset; - u8 inl; - u8 ts_requested; -}; + u32 nr_txbb; + u32 nr_bytes; + u8 linear; + u8 data_offset; + u8 inl; + u8 ts_requested; +} ____cacheline_aligned_in_smp; #define MLX4_EN_BIT_DESC_OWN 0x80000000 @@ -253,40 +253,46 @@ struct mlx4_en_rx_alloc { }; struct mlx4_en_tx_ring { + /* cache line used and dirtied in tx completion + * (mlx4_en_free_tx_buf()) + */ + u32 last_nr_txbb; + u32 cons; + unsigned long wake_queue; + + /* cache line used and dirtied in mlx4_en_xmit() */ + u32 prod ____cacheline_aligned_in_smp; + unsigned long bytes; + unsigned long packets; + unsigned long tx_csum; + unsigned long tso_packets; + unsigned long xmit_more; + struct mlx4_bf bf; + unsigned long queue_stopped; + + /* Following part should be mostly read */ + cpumask_t affinity_mask; + struct mlx4_qp qp; struct mlx4_hwq_resources wqres; - u32 size ; /* number of TXBBs */ - u32 size_mask; - u16 stride; - u16 cqn; /* index of port CQ associated with this ring */ - u32 prod; - u32 cons; - u32 buf_size; - u32 doorbell_qpn; - void *buf; - struct mlx4_en_tx_info *tx_info; - u8 *bounce_buf; - u8 queue_index; - cpumask_t affinity_mask; - u32 last_nr_txbb; - struct mlx4_qp qp; - struct mlx4_qp_context context; - int qpn; - enum mlx4_qp_state qp_state; - struct mlx4_srq dummy; - unsigned long bytes; - unsigned long packets; - unsigned long tx_csum; - unsigned long queue_stopped; - unsigned long wake_queue; - unsigned long tso_packets; - unsigned long xmit_more; - struct mlx4_bf bf; - bool bf_enabled; - bool bf_alloced; - struct netdev_queue *tx_queue; - int hwtstamp_tx_type; - int inline_thold; -}; + u32 size; /* number of TXBBs */ + u32 size_mask; + u16 stride; + u16 cqn; /* index of port CQ associated with this ring */ + u32 buf_size; + u32 doorbell_qpn; + void *buf; + struct mlx4_en_tx_info *tx_info; + u8 *bounce_buf; + struct mlx4_qp_context context; + int qpn; + enum mlx4_qp_state qp_state; + u8 queue_index; + bool bf_enabled; + bool bf_alloced; + struct netdev_queue *tx_queue; + int hwtstamp_tx_type; + int inline_thold; +} ____cacheline_aligned_in_smp; struct mlx4_en_rx_desc { /* actual number of entries depends on rx ring stride */ From 6a4e81211f475561ed87c613216f981fbef8b7fc Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:11 +0300 Subject: [PATCH 03/14] net/mlx4_en: Avoid calling bswap in tx fast path - doorbell_qpn is stored in the cpu_to_be32() way to avoid bswap() in fast path. - mdev->mr.key stored in ring->mr_key to also avoid bswap() and access to cold cache line. Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 17 ++++++++++------- drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 3 ++- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index eaf23eb7266a0..322cda32ef808 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -195,7 +195,8 @@ int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv, memset(ring->buf, 0, ring->buf_size); ring->qp_state = MLX4_QP_STATE_RST; - ring->doorbell_qpn = ring->qp.qpn << 8; + ring->doorbell_qpn = cpu_to_be32(ring->qp.qpn << 8); + ring->mr_key = cpu_to_be32(mdev->mr.key); mlx4_en_fill_qp_context(priv, ring->size, ring->stride, 1, 0, ring->qpn, ring->cqn, user_prio, &ring->context); @@ -654,7 +655,6 @@ static void mlx4_bf_copy(void __iomem *dst, const void *src, netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) { struct mlx4_en_priv *priv = netdev_priv(dev); - struct mlx4_en_dev *mdev = priv->mdev; struct device *ddev = priv->ddev; struct mlx4_en_tx_ring *ring; struct mlx4_en_tx_desc *tx_desc; @@ -769,7 +769,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) goto tx_drop_unmap; data->addr = cpu_to_be64(dma); - data->lkey = cpu_to_be32(mdev->mr.key); + data->lkey = ring->mr_key; wmb(); data->byte_count = cpu_to_be32(skb_frag_size(frag)); --data; @@ -787,7 +787,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) goto tx_drop_unmap; data->addr = cpu_to_be64(dma); - data->lkey = cpu_to_be32(mdev->mr.key); + data->lkey = ring->mr_key; wmb(); data->byte_count = cpu_to_be32(byte_count); } @@ -879,9 +879,12 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) send_doorbell = !skb->xmit_more || netif_xmit_stopped(ring->tx_queue); + real_size = (real_size / 16) & 0x3f; + if (ring->bf_enabled && desc_size <= MAX_BF && !bounce && !vlan_tx_tag_present(skb) && send_doorbell) { - tx_desc->ctrl.bf_qpn |= cpu_to_be32(ring->doorbell_qpn); + tx_desc->ctrl.bf_qpn = ring->doorbell_qpn | + cpu_to_be32(real_size); op_own |= htonl((bf_index & 0xffff) << 8); /* Ensure new descriptor hits memory @@ -911,8 +914,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) tx_desc->ctrl.owner_opcode = op_own; if (send_doorbell) { wmb(); - iowrite32be(ring->doorbell_qpn, - ring->bf.uar->map + MLX4_SEND_DOORBELL); + iowrite32(ring->doorbell_qpn, + ring->bf.uar->map + MLX4_SEND_DOORBELL); } else { ring->xmit_more++; } diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h index b7bde95e05fe1..ab34461e628ce 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h @@ -279,7 +279,8 @@ struct mlx4_en_tx_ring { u16 stride; u16 cqn; /* index of port CQ associated with this ring */ u32 buf_size; - u32 doorbell_qpn; + __be32 doorbell_qpn; + __be32 mr_key; void *buf; struct mlx4_en_tx_info *tx_info; u8 *bounce_buf; From dc9b06d156cefb95f7f6a3ac0521a3efa31d6805 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:12 +0300 Subject: [PATCH 04/14] net/mlx4_en: tx_info allocated with kmalloc() instead of vmalloc() Try to allocate using kmalloc_node() first, only on failure use vmalloc() Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index 322cda32ef808..14479068001f4 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -68,7 +68,7 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv, ring->inline_thold = priv->prof->inline_thold; tmp = size * sizeof(struct mlx4_en_tx_info); - ring->tx_info = vmalloc_node(tmp, node); + ring->tx_info = kmalloc_node(tmp, GFP_KERNEL | __GFP_NOWARN, node); if (!ring->tx_info) { ring->tx_info = vmalloc(tmp); if (!ring->tx_info) { @@ -151,7 +151,7 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv, kfree(ring->bounce_buf); ring->bounce_buf = NULL; err_info: - vfree(ring->tx_info); + kvfree(ring->tx_info); ring->tx_info = NULL; err_ring: kfree(ring); @@ -174,7 +174,7 @@ void mlx4_en_destroy_tx_ring(struct mlx4_en_priv *priv, mlx4_free_hwq_res(mdev->dev, &ring->wqres, ring->buf_size); kfree(ring->bounce_buf); ring->bounce_buf = NULL; - vfree(ring->tx_info); + kvfree(ring->tx_info); ring->tx_info = NULL; kfree(ring); *pring = NULL; From 3d03641cb4ea050f969dd3ab34113adb95287f36 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:13 +0300 Subject: [PATCH 05/14] net/mlx4_en: Avoid a cache line miss in TX completion for single frag skb's Add frag0_dma/frag0_byte_count into mlx4_en_tx_info to avoid a cache line miss in TX completion for frames having one dma element. (We avoid reading back the tx descriptor) Note this could be extended to 2/3 dma elements later, as we have free room in mlx4_en_tx_info Also, mlx4_en_free_tx_desc() no longer accesses skb_shinfo(). We use a new nr_maps fields in mlx4_en_tx_info to avoid 2 or 3 cache misses. Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 83 +++++++++++--------- drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 3 + 2 files changed, 49 insertions(+), 37 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index 14479068001f4..edc4a88103681 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -259,38 +259,40 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv, struct mlx4_en_tx_ring *ring, int index, u8 owner, u64 timestamp) { - struct mlx4_en_dev *mdev = priv->mdev; struct mlx4_en_tx_info *tx_info = &ring->tx_info[index]; struct mlx4_en_tx_desc *tx_desc = ring->buf + index * TXBB_SIZE; struct mlx4_wqe_data_seg *data = (void *) tx_desc + tx_info->data_offset; - struct sk_buff *skb = tx_info->skb; - struct skb_frag_struct *frag; void *end = ring->buf + ring->buf_size; - int frags = skb_shinfo(skb)->nr_frags; + struct sk_buff *skb = tx_info->skb; + int nr_maps = tx_info->nr_maps; int i; - struct skb_shared_hwtstamps hwts; - if (timestamp) { - mlx4_en_fill_hwtstamps(mdev, &hwts, timestamp); + if (unlikely(timestamp)) { + struct skb_shared_hwtstamps hwts; + + mlx4_en_fill_hwtstamps(priv->mdev, &hwts, timestamp); skb_tstamp_tx(skb, &hwts); } /* Optimize the common case when there are no wraparounds */ if (likely((void *) tx_desc + tx_info->nr_txbb * TXBB_SIZE <= end)) { if (!tx_info->inl) { - if (tx_info->linear) { + if (tx_info->linear) dma_unmap_single(priv->ddev, - (dma_addr_t) be64_to_cpu(data->addr), - be32_to_cpu(data->byte_count), - PCI_DMA_TODEVICE); - ++data; - } - - for (i = 0; i < frags; i++) { - frag = &skb_shinfo(skb)->frags[i]; + tx_info->map0_dma, + tx_info->map0_byte_count, + PCI_DMA_TODEVICE); + else + dma_unmap_page(priv->ddev, + tx_info->map0_dma, + tx_info->map0_byte_count, + PCI_DMA_TODEVICE); + for (i = 1; i < nr_maps; i++) { + data++; dma_unmap_page(priv->ddev, - (dma_addr_t) be64_to_cpu(data[i].addr), - skb_frag_size(frag), PCI_DMA_TODEVICE); + (dma_addr_t)be64_to_cpu(data->addr), + be32_to_cpu(data->byte_count), + PCI_DMA_TODEVICE); } } } else { @@ -299,23 +301,25 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv, data = ring->buf + ((void *)data - end); } - if (tx_info->linear) { + if (tx_info->linear) dma_unmap_single(priv->ddev, - (dma_addr_t) be64_to_cpu(data->addr), - be32_to_cpu(data->byte_count), - PCI_DMA_TODEVICE); - ++data; - } - - for (i = 0; i < frags; i++) { + tx_info->map0_dma, + tx_info->map0_byte_count, + PCI_DMA_TODEVICE); + else + dma_unmap_page(priv->ddev, + tx_info->map0_dma, + tx_info->map0_byte_count, + PCI_DMA_TODEVICE); + for (i = 1; i < nr_maps; i++) { + data++; /* Check for wraparound before unmapping */ if ((void *) data >= end) data = ring->buf; - frag = &skb_shinfo(skb)->frags[i]; dma_unmap_page(priv->ddev, - (dma_addr_t) be64_to_cpu(data->addr), - skb_frag_size(frag), PCI_DMA_TODEVICE); - ++data; + (dma_addr_t)be64_to_cpu(data->addr), + be32_to_cpu(data->byte_count), + PCI_DMA_TODEVICE); } } } @@ -751,19 +755,22 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) tx_info->linear = (lso_header_size < skb_headlen(skb) && !is_inline(ring->inline_thold, skb, NULL)) ? 1 : 0; - data += skb_shinfo(skb)->nr_frags + tx_info->linear - 1; + tx_info->nr_maps = skb_shinfo(skb)->nr_frags + tx_info->linear; + data += tx_info->nr_maps - 1; if (is_inline(ring->inline_thold, skb, &fragptr)) { tx_info->inl = 1; } else { + dma_addr_t dma = 0; + u32 byte_count = 0; + /* Map fragments if any */ for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) { const struct skb_frag_struct *frag; - dma_addr_t dma; - frag = &skb_shinfo(skb)->frags[i]; + byte_count = skb_frag_size(frag); dma = skb_frag_dma_map(ddev, frag, - 0, skb_frag_size(frag), + 0, byte_count, DMA_TO_DEVICE); if (dma_mapping_error(ddev, dma)) goto tx_drop_unmap; @@ -771,14 +778,13 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) data->addr = cpu_to_be64(dma); data->lkey = ring->mr_key; wmb(); - data->byte_count = cpu_to_be32(skb_frag_size(frag)); + data->byte_count = cpu_to_be32(byte_count); --data; } /* Map linear part if needed */ if (tx_info->linear) { - u32 byte_count = skb_headlen(skb) - lso_header_size; - dma_addr_t dma; + byte_count = skb_headlen(skb) - lso_header_size; dma = dma_map_single(ddev, skb->data + lso_header_size, byte_count, @@ -792,6 +798,9 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) data->byte_count = cpu_to_be32(byte_count); } tx_info->inl = 0; + /* tx completion can avoid cache line miss for common cases */ + tx_info->map0_dma = dma; + tx_info->map0_byte_count = byte_count; } /* diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h index ab34461e628ce..a90403000577f 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h @@ -216,12 +216,15 @@ enum cq_type { struct mlx4_en_tx_info { struct sk_buff *skb; + dma_addr_t map0_dma; + u32 map0_byte_count; u32 nr_txbb; u32 nr_bytes; u8 linear; u8 data_offset; u8 inl; u8 ts_requested; + u8 nr_maps; } ____cacheline_aligned_in_smp; From 29d40c903247596c954446639116467eb6689bb7 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:14 +0300 Subject: [PATCH 06/14] net/mlx4_en: Use prefetch in tx path mlx4_en_free_tx_desc() uses a prefetchw(&skb->users) to speed up consume_skb() prefetchw(&ring->tx_queue->dql) to speed up BQL update Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index edc4a88103681..b96627c4972fd 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include @@ -267,6 +268,11 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv, int nr_maps = tx_info->nr_maps; int i; + /* We do not touch skb here, so prefetch skb->users location + * to speedup consume_skb() + */ + prefetchw(&skb->users); + if (unlikely(timestamp)) { struct skb_shared_hwtstamps hwts; @@ -385,6 +391,7 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev, if (!priv->port_up) return true; + prefetchw(&ring->tx_queue->dql.limit); index = cons_index & size_mask; cqe = mlx4_en_get_cqe(buf, index, priv->cqe_size) + factor; ring_index = ring->cons & size_mask; @@ -722,6 +729,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) } } + prefetchw(&ring->tx_queue->dql); + /* Track current inflight packets for performance analysis */ AVG_PERF_COUNTER(priv->pstats.inflight_avg, (u32) (ring->prod - ring->cons - 1)); From fb1843ee72c7b2ed784bf88ad79c6ccc2f652499 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:15 +0300 Subject: [PATCH 07/14] net/mlx4_en: Avoid false sharing in mlx4_en_en_process_tx_cq() mlx4_en_process_tx_cq() carefully fetches and writes ring->last_nr_txbb and ring->cons only one time to avoid false sharing Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index b96627c4972fd..d9aaeb2d019ff 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -387,6 +387,8 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev, u64 timestamp = 0; int done = 0; int budget = priv->tx_work_limit; + u32 last_nr_txbb; + u32 ring_cons; if (!priv->port_up) return true; @@ -394,7 +396,9 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev, prefetchw(&ring->tx_queue->dql.limit); index = cons_index & size_mask; cqe = mlx4_en_get_cqe(buf, index, priv->cqe_size) + factor; - ring_index = ring->cons & size_mask; + last_nr_txbb = ACCESS_ONCE(ring->last_nr_txbb); + ring_cons = ACCESS_ONCE(ring->cons); + ring_index = ring_cons & size_mask; stamp_index = ring_index; /* Process all completed CQEs */ @@ -419,19 +423,19 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev, new_index = be16_to_cpu(cqe->wqe_index) & size_mask; do { - txbbs_skipped += ring->last_nr_txbb; - ring_index = (ring_index + ring->last_nr_txbb) & size_mask; + txbbs_skipped += last_nr_txbb; + ring_index = (ring_index + last_nr_txbb) & size_mask; if (ring->tx_info[ring_index].ts_requested) timestamp = mlx4_en_get_cqe_ts(cqe); /* free next descriptor */ - ring->last_nr_txbb = mlx4_en_free_tx_desc( + last_nr_txbb = mlx4_en_free_tx_desc( priv, ring, ring_index, - !!((ring->cons + txbbs_skipped) & + !!((ring_cons + txbbs_skipped) & ring->size), timestamp); mlx4_en_stamp_wqe(priv, ring, stamp_index, - !!((ring->cons + txbbs_stamp) & + !!((ring_cons + txbbs_stamp) & ring->size)); stamp_index = ring_index; txbbs_stamp = txbbs_skipped; @@ -452,7 +456,11 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev, mcq->cons_index = cons_index; mlx4_cq_set_ci(mcq); wmb(); - ring->cons += txbbs_skipped; + + /* we want to dirty this cache line once */ + ACCESS_ONCE(ring->last_nr_txbb) = last_nr_txbb; + ACCESS_ONCE(ring->cons) = ring_cons + txbbs_skipped; + netdev_tx_completed_queue(ring->tx_queue, packets, bytes); /* From f905c79e12791d09bbfd9ba7b672fbeb19c1e7c2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:16 +0300 Subject: [PATCH 08/14] net/mlx4_en: mlx4_en_xmit() reads ring->cons once, and ahead of time to avoid stalls Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index d9aaeb2d019ff..99875c8d70c15 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -691,10 +691,17 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) void *fragptr; bool bounce = false; bool send_doorbell; + u32 ring_cons; if (!priv->port_up) goto tx_drop; + tx_ind = skb_get_queue_mapping(skb); + ring = priv->tx_ring[tx_ind]; + + /* fetch ring->cons far ahead before needing it to avoid stall */ + ring_cons = ACCESS_ONCE(ring->cons); + real_size = get_real_size(skb, dev, &lso_header_size); if (unlikely(!real_size)) goto tx_drop; @@ -708,13 +715,11 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) goto tx_drop; } - tx_ind = skb->queue_mapping; - ring = priv->tx_ring[tx_ind]; if (vlan_tx_tag_present(skb)) vlan_tag = vlan_tx_tag_get(skb); /* Check available TXBBs And 2K spare for prefetch */ - if (unlikely(((int)(ring->prod - ring->cons)) > + if (unlikely(((int)(ring->prod - ring_cons)) > ring->size - HEADROOM - MAX_DESC_TXBBS)) { /* every full Tx ring stops queue */ netif_tx_stop_queue(ring->tx_queue); @@ -728,7 +733,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) */ wmb(); - if (unlikely(((int)(ring->prod - ring->cons)) <= + ring_cons = ACCESS_ONCE(ring->cons); + if (unlikely(((int)(ring->prod - ring_cons)) <= ring->size - HEADROOM - MAX_DESC_TXBBS)) { netif_tx_wake_queue(ring->tx_queue); ring->wake_queue++; @@ -741,7 +747,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) /* Track current inflight packets for performance analysis */ AVG_PERF_COUNTER(priv->pstats.inflight_avg, - (u32) (ring->prod - ring->cons - 1)); + (u32)(ring->prod - ring_cons - 1)); /* Packet is good - grab an index and transmit it */ index = ring->prod & ring->size_mask; From b9d8839a44092cb4268ef2813c34d5dbf3363603 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:17 +0300 Subject: [PATCH 09/14] net/mlx4_en: Use local var in tx flow for skb_shinfo(skb) Acces skb_shinfo(skb) once in tx flow. Also, rename @i variable to @i_frag to avoid confusion, as the "goto tx_drop_unmap;" relied on this @i variable. Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 58 +++++++++++++--------- 1 file changed, 34 insertions(+), 24 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index 99875c8d70c15..aa05b09a0d0e5 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -532,13 +532,14 @@ static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv, } static bool is_inline(int inline_thold, const struct sk_buff *skb, + const struct skb_shared_info *shinfo, void **pfrag) { void *ptr; if (inline_thold && !skb_is_gso(skb) && skb->len <= inline_thold) { - if (skb_shinfo(skb)->nr_frags == 1) { - ptr = skb_frag_address_safe(&skb_shinfo(skb)->frags[0]); + if (shinfo->nr_frags == 1) { + ptr = skb_frag_address_safe(&shinfo->frags[0]); if (unlikely(!ptr)) return 0; @@ -546,7 +547,7 @@ static bool is_inline(int inline_thold, const struct sk_buff *skb, *pfrag = ptr; return 1; - } else if (unlikely(skb_shinfo(skb)->nr_frags)) + } else if (unlikely(shinfo->nr_frags)) return 0; else return 1; @@ -567,18 +568,19 @@ static int inline_size(const struct sk_buff *skb) } static int get_real_size(const struct sk_buff *skb, + const struct skb_shared_info *shinfo, struct net_device *dev, int *lso_header_size) { struct mlx4_en_priv *priv = netdev_priv(dev); int real_size; - if (skb_is_gso(skb)) { + if (shinfo->gso_size) { if (skb->encapsulation) *lso_header_size = (skb_inner_transport_header(skb) - skb->data) + inner_tcp_hdrlen(skb); else *lso_header_size = skb_transport_offset(skb) + tcp_hdrlen(skb); - real_size = CTRL_SIZE + skb_shinfo(skb)->nr_frags * DS_SIZE + + real_size = CTRL_SIZE + shinfo->nr_frags * DS_SIZE + ALIGN(*lso_header_size + 4, DS_SIZE); if (unlikely(*lso_header_size != skb_headlen(skb))) { /* We add a segment for the skb linear buffer only if @@ -593,8 +595,8 @@ static int get_real_size(const struct sk_buff *skb, } } else { *lso_header_size = 0; - if (!is_inline(priv->prof->inline_thold, skb, NULL)) - real_size = CTRL_SIZE + (skb_shinfo(skb)->nr_frags + 1) * DS_SIZE; + if (!is_inline(priv->prof->inline_thold, skb, shinfo, NULL)) + real_size = CTRL_SIZE + (shinfo->nr_frags + 1) * DS_SIZE; else real_size = inline_size(skb); } @@ -604,6 +606,7 @@ static int get_real_size(const struct sk_buff *skb, static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc, const struct sk_buff *skb, + const struct skb_shared_info *shinfo, int real_size, u16 *vlan_tag, int tx_ind, void *fragptr) { @@ -619,9 +622,9 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc, MIN_PKT_LEN - skb->len); } skb_copy_from_linear_data(skb, inl + 1, skb_headlen(skb)); - if (skb_shinfo(skb)->nr_frags) + if (shinfo->nr_frags) memcpy(((void *)(inl + 1)) + skb_headlen(skb), fragptr, - skb_frag_size(&skb_shinfo(skb)->frags[0])); + skb_frag_size(&shinfo->frags[0])); } else { inl->byte_count = cpu_to_be32(1 << 31 | spc); @@ -639,9 +642,10 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc, inl = (void *) (inl + 1) + spc; skb_copy_from_linear_data_offset(skb, spc, inl + 1, skb_headlen(skb) - spc); - if (skb_shinfo(skb)->nr_frags) + if (shinfo->nr_frags) memcpy(((void *)(inl + 1)) + skb_headlen(skb) - spc, - fragptr, skb_frag_size(&skb_shinfo(skb)->frags[0])); + fragptr, + skb_frag_size(&shinfo->frags[0])); } wmb(); @@ -673,6 +677,7 @@ static void mlx4_bf_copy(void __iomem *dst, const void *src, netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) { + struct skb_shared_info *shinfo = skb_shinfo(skb); struct mlx4_en_priv *priv = netdev_priv(dev); struct device *ddev = priv->ddev; struct mlx4_en_tx_ring *ring; @@ -686,7 +691,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) u32 index, bf_index; __be32 op_own; u16 vlan_tag = 0; - int i; + int i_frag; int lso_header_size; void *fragptr; bool bounce = false; @@ -702,7 +707,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) /* fetch ring->cons far ahead before needing it to avoid stall */ ring_cons = ACCESS_ONCE(ring->cons); - real_size = get_real_size(skb, dev, &lso_header_size); + real_size = get_real_size(skb, shinfo, dev, &lso_header_size); if (unlikely(!real_size)) goto tx_drop; @@ -776,21 +781,22 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) tx_info->data_offset = (void *)data - (void *)tx_desc; tx_info->linear = (lso_header_size < skb_headlen(skb) && - !is_inline(ring->inline_thold, skb, NULL)) ? 1 : 0; + !is_inline(ring->inline_thold, skb, shinfo, NULL)) ? 1 : 0; - tx_info->nr_maps = skb_shinfo(skb)->nr_frags + tx_info->linear; + tx_info->nr_maps = shinfo->nr_frags + tx_info->linear; data += tx_info->nr_maps - 1; - if (is_inline(ring->inline_thold, skb, &fragptr)) { + if (is_inline(ring->inline_thold, skb, shinfo, &fragptr)) { tx_info->inl = 1; } else { dma_addr_t dma = 0; u32 byte_count = 0; /* Map fragments if any */ - for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) { + for (i_frag = shinfo->nr_frags - 1; i_frag >= 0; i_frag--) { const struct skb_frag_struct *frag; - frag = &skb_shinfo(skb)->frags[i]; + + frag = &shinfo->frags[i_frag]; byte_count = skb_frag_size(frag); dma = skb_frag_dma_map(ddev, frag, 0, byte_count, @@ -858,6 +864,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) /* Handle LSO (TSO) packets */ if (lso_header_size) { + int i; + /* Mark opcode as LSO */ op_own = cpu_to_be32(MLX4_OPCODE_LSO | (1 << 6)) | ((ring->prod & ring->size) ? @@ -865,15 +873,16 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) /* Fill in the LSO prefix */ tx_desc->lso.mss_hdr_size = cpu_to_be32( - skb_shinfo(skb)->gso_size << 16 | lso_header_size); + shinfo->gso_size << 16 | lso_header_size); /* Copy headers; * note that we already verified that it is linear */ memcpy(tx_desc->lso.header, skb->data, lso_header_size); ring->tso_packets++; - i = ((skb->len - lso_header_size) / skb_shinfo(skb)->gso_size) + - !!((skb->len - lso_header_size) % skb_shinfo(skb)->gso_size); + + i = ((skb->len - lso_header_size) / shinfo->gso_size) + + !!((skb->len - lso_header_size) % shinfo->gso_size); tx_info->nr_bytes = skb->len + (i - 1) * lso_header_size; ring->packets += i; } else { @@ -889,7 +898,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len); if (tx_info->inl) { - build_inline_wqe(tx_desc, skb, real_size, &vlan_tag, tx_ind, fragptr); + build_inline_wqe(tx_desc, skb, shinfo, real_size, &vlan_tag, + tx_ind, fragptr); tx_info->inl = 1; } @@ -958,8 +968,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) tx_drop_unmap: en_err(priv, "DMA mapping error\n"); - for (i++; i < skb_shinfo(skb)->nr_frags; i++) { - data++; + while (++i_frag < shinfo->nr_frags) { + ++data; dma_unmap_page(ddev, (dma_addr_t) be64_to_cpu(data->addr), be32_to_cpu(data->byte_count), PCI_DMA_TODEVICE); From e533ac7ea00c39f5ef4ab0976dd2662d50fa42a1 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:18 +0300 Subject: [PATCH 10/14] net/mlx4_en: Use local var for skb_headlen(skb) Access skb_headlen() once in tx flow Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index aa05b09a0d0e5..e00841aa03c3c 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -612,6 +612,7 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc, { struct mlx4_wqe_inline_seg *inl = &tx_desc->inl; int spc = MLX4_INLINE_ALIGN - CTRL_SIZE - sizeof *inl; + unsigned int hlen = skb_headlen(skb); if (skb->len <= spc) { if (likely(skb->len >= MIN_PKT_LEN)) { @@ -621,19 +622,19 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc, memset(((void *)(inl + 1)) + skb->len, 0, MIN_PKT_LEN - skb->len); } - skb_copy_from_linear_data(skb, inl + 1, skb_headlen(skb)); + skb_copy_from_linear_data(skb, inl + 1, hlen); if (shinfo->nr_frags) - memcpy(((void *)(inl + 1)) + skb_headlen(skb), fragptr, + memcpy(((void *)(inl + 1)) + hlen, fragptr, skb_frag_size(&shinfo->frags[0])); } else { inl->byte_count = cpu_to_be32(1 << 31 | spc); - if (skb_headlen(skb) <= spc) { - skb_copy_from_linear_data(skb, inl + 1, skb_headlen(skb)); - if (skb_headlen(skb) < spc) { - memcpy(((void *)(inl + 1)) + skb_headlen(skb), - fragptr, spc - skb_headlen(skb)); - fragptr += spc - skb_headlen(skb); + if (hlen <= spc) { + skb_copy_from_linear_data(skb, inl + 1, hlen); + if (hlen < spc) { + memcpy(((void *)(inl + 1)) + hlen, + fragptr, spc - hlen); + fragptr += spc - hlen; } inl = (void *) (inl + 1) + spc; memcpy(((void *)(inl + 1)), fragptr, skb->len - spc); @@ -641,9 +642,9 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc, skb_copy_from_linear_data(skb, inl + 1, spc); inl = (void *) (inl + 1) + spc; skb_copy_from_linear_data_offset(skb, spc, inl + 1, - skb_headlen(skb) - spc); + hlen - spc); if (shinfo->nr_frags) - memcpy(((void *)(inl + 1)) + skb_headlen(skb) - spc, + memcpy(((void *)(inl + 1)) + hlen - spc, fragptr, skb_frag_size(&shinfo->frags[0])); } From e70602a8b87649e9f7742d96929a8d83618fa320 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:19 +0300 Subject: [PATCH 11/14] net/mlx4_en: tx_info->ts_requested was not cleared Properly clear tx_info->ts_requested Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index e00841aa03c3c..2c03b55204838 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -837,6 +837,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) * For timestamping add flag to skb_shinfo and * set flag for further reference */ + tx_info->ts_requested = 0; if (unlikely(ring->hwtstamp_tx_type == HWTSTAMP_TX_ON && shinfo->tx_flags & SKBTX_HW_TSTAMP)) { shinfo->tx_flags |= SKBTX_IN_PROGRESS; From acea73d671b25bfbbe6b8ceef949f4ac62c260c0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:20 +0300 Subject: [PATCH 12/14] net/mlx4_en: Enable the compiler to make is_inline() inlined Reorganize code to call is_inline() once, so compiler can inline it Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_tx.c | 67 ++++++++++++---------- 1 file changed, 38 insertions(+), 29 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index 2c03b55204838..f0080c5417c3f 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -531,29 +531,32 @@ static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv, return ring->buf + index * TXBB_SIZE; } +/* Decide if skb can be inlined in tx descriptor to avoid dma mapping + * + * It seems strange we do not simply use skb_copy_bits(). + * This would allow to inline all skbs iff skb->len <= inline_thold + * + * Note that caller already checked skb was not a gso packet + */ static bool is_inline(int inline_thold, const struct sk_buff *skb, const struct skb_shared_info *shinfo, void **pfrag) { void *ptr; - if (inline_thold && !skb_is_gso(skb) && skb->len <= inline_thold) { - if (shinfo->nr_frags == 1) { - ptr = skb_frag_address_safe(&shinfo->frags[0]); - if (unlikely(!ptr)) - return 0; - - if (pfrag) - *pfrag = ptr; + if (skb->len > inline_thold || !inline_thold) + return false; - return 1; - } else if (unlikely(shinfo->nr_frags)) - return 0; - else - return 1; + if (shinfo->nr_frags == 1) { + ptr = skb_frag_address_safe(&shinfo->frags[0]); + if (unlikely(!ptr)) + return false; + *pfrag = ptr; + return true; } - - return 0; + if (shinfo->nr_frags) + return false; + return true; } static int inline_size(const struct sk_buff *skb) @@ -570,12 +573,15 @@ static int inline_size(const struct sk_buff *skb) static int get_real_size(const struct sk_buff *skb, const struct skb_shared_info *shinfo, struct net_device *dev, - int *lso_header_size) + int *lso_header_size, + bool *inline_ok, + void **pfrag) { struct mlx4_en_priv *priv = netdev_priv(dev); int real_size; if (shinfo->gso_size) { + *inline_ok = false; if (skb->encapsulation) *lso_header_size = (skb_inner_transport_header(skb) - skb->data) + inner_tcp_hdrlen(skb); else @@ -595,10 +601,14 @@ static int get_real_size(const struct sk_buff *skb, } } else { *lso_header_size = 0; - if (!is_inline(priv->prof->inline_thold, skb, shinfo, NULL)) - real_size = CTRL_SIZE + (shinfo->nr_frags + 1) * DS_SIZE; - else + *inline_ok = is_inline(priv->prof->inline_thold, skb, + shinfo, pfrag); + + if (*inline_ok) real_size = inline_size(skb); + else + real_size = CTRL_SIZE + + (shinfo->nr_frags + 1) * DS_SIZE; } return real_size; @@ -694,9 +704,10 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) u16 vlan_tag = 0; int i_frag; int lso_header_size; - void *fragptr; + void *fragptr = NULL; bool bounce = false; bool send_doorbell; + bool inline_ok; u32 ring_cons; if (!priv->port_up) @@ -708,7 +719,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) /* fetch ring->cons far ahead before needing it to avoid stall */ ring_cons = ACCESS_ONCE(ring->cons); - real_size = get_real_size(skb, shinfo, dev, &lso_header_size); + real_size = get_real_size(skb, shinfo, dev, &lso_header_size, + &inline_ok, &fragptr); if (unlikely(!real_size)) goto tx_drop; @@ -781,15 +793,15 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) /* valid only for none inline segments */ tx_info->data_offset = (void *)data - (void *)tx_desc; + tx_info->inl = inline_ok; + tx_info->linear = (lso_header_size < skb_headlen(skb) && - !is_inline(ring->inline_thold, skb, shinfo, NULL)) ? 1 : 0; + !inline_ok) ? 1 : 0; tx_info->nr_maps = shinfo->nr_frags + tx_info->linear; data += tx_info->nr_maps - 1; - if (is_inline(ring->inline_thold, skb, shinfo, &fragptr)) { - tx_info->inl = 1; - } else { + if (!tx_info->inl) { dma_addr_t dma = 0; u32 byte_count = 0; @@ -827,7 +839,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) wmb(); data->byte_count = cpu_to_be32(byte_count); } - tx_info->inl = 0; /* tx completion can avoid cache line miss for common cases */ tx_info->map0_dma = dma; tx_info->map0_byte_count = byte_count; @@ -899,11 +910,9 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev) netdev_tx_sent_queue(ring->tx_queue, tx_info->nr_bytes); AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len); - if (tx_info->inl) { + if (tx_info->inl) build_inline_wqe(tx_desc, skb, shinfo, real_size, &vlan_tag, tx_ind, fragptr); - tx_info->inl = 1; - } if (skb->encapsulation) { struct iphdr *ipv4 = (struct iphdr *)skb_inner_network_header(skb); From 1255a5055449781a92076fc5429952f2b33cf309 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:21 +0300 Subject: [PATCH 13/14] ethtool: Ethtool parameter to dynamically change tx_copybreak Use new ethtool [sg]et_tunable() to set tx_copybread (inline threshold) Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- include/uapi/linux/ethtool.h | 1 + net/core/ethtool.c | 1 + 2 files changed, 2 insertions(+) diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h index 7a364f2f3d3fa..99b43056a6feb 100644 --- a/include/uapi/linux/ethtool.h +++ b/include/uapi/linux/ethtool.h @@ -212,6 +212,7 @@ struct ethtool_value { enum tunable_id { ETHTOOL_ID_UNSPEC, ETHTOOL_RX_COPYBREAK, + ETHTOOL_TX_COPYBREAK, }; enum tunable_type_id { diff --git a/net/core/ethtool.c b/net/core/ethtool.c index 27e61b8865208..1600aa24d36bc 100644 --- a/net/core/ethtool.c +++ b/net/core/ethtool.c @@ -1625,6 +1625,7 @@ static int ethtool_tunable_valid(const struct ethtool_tunable *tuna) { switch (tuna->id) { case ETHTOOL_RX_COPYBREAK: + case ETHTOOL_TX_COPYBREAK: if (tuna->len != sizeof(u32) || tuna->type_id != ETHTOOL_TUNABLE_U32) return -EINVAL; From 1556b8746e52501fdfaadd65837baaa63a9fa937 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 5 Oct 2014 12:35:22 +0300 Subject: [PATCH 14/14] net/mlx4_en: Use the new tx_copybreak to set inline threshold Instead of setting inline threshold using module parameter only on driver load, use set_tunable() to set it dynamically. No need to store the threshold per ring, using instead the netdev global priv->prof->inline_thold Initial value still is set using the module parameter, therefore backward compatability is kept. Signed-off-by: Eric Dumazet Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- .../net/ethernet/mellanox/mlx4/en_ethtool.c | 44 +++++++++++++++++++ drivers/net/ethernet/mellanox/mlx4/en_tx.c | 1 - drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 - 3 files changed, 44 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c index 42c9f8b09a6e2..ae83da9cd18a3 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c @@ -1267,6 +1267,48 @@ static u32 mlx4_en_get_priv_flags(struct net_device *dev) return priv->pflags; } +static int mlx4_en_get_tunable(struct net_device *dev, + const struct ethtool_tunable *tuna, + void *data) +{ + const struct mlx4_en_priv *priv = netdev_priv(dev); + int ret = 0; + + switch (tuna->id) { + case ETHTOOL_TX_COPYBREAK: + *(u32 *)data = priv->prof->inline_thold; + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + +static int mlx4_en_set_tunable(struct net_device *dev, + const struct ethtool_tunable *tuna, + const void *data) +{ + struct mlx4_en_priv *priv = netdev_priv(dev); + int val, ret = 0; + + switch (tuna->id) { + case ETHTOOL_TX_COPYBREAK: + val = *(u32 *)data; + if (val < MIN_PKT_LEN || val > MAX_INLINE) + ret = -EINVAL; + else + priv->prof->inline_thold = val; + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + const struct ethtool_ops mlx4_en_ethtool_ops = { .get_drvinfo = mlx4_en_get_drvinfo, @@ -1297,6 +1339,8 @@ const struct ethtool_ops mlx4_en_ethtool_ops = { .get_ts_info = mlx4_en_get_ts_info, .set_priv_flags = mlx4_en_set_priv_flags, .get_priv_flags = mlx4_en_get_priv_flags, + .get_tunable = mlx4_en_get_tunable, + .set_tunable = mlx4_en_set_tunable, }; diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c index f0080c5417c3f..92a7cf46d9af9 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c @@ -66,7 +66,6 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv, ring->size = size; ring->size_mask = size - 1; ring->stride = stride; - ring->inline_thold = priv->prof->inline_thold; tmp = size * sizeof(struct mlx4_en_tx_info); ring->tx_info = kmalloc_node(tmp, GFP_KERNEL | __GFP_NOWARN, node); diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h index a90403000577f..8fef65840b3b5 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h @@ -295,7 +295,6 @@ struct mlx4_en_tx_ring { bool bf_alloced; struct netdev_queue *tx_queue; int hwtstamp_tx_type; - int inline_thold; } ____cacheline_aligned_in_smp; struct mlx4_en_rx_desc {