From 6f429223b31c550b835b4f066ac034d0cf0cc71e Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Tue, 17 Jan 2017 08:37:13 -0800 Subject: [PATCH] ixgbe: Add support for build_skb This patch adds build_skb support to the Rx path. There are several advantages to this change. 1. It avoids the memcpy and skb->head allocation for small packets which improves performance by about 5% in my tests. 2. It avoids the memcpy, skb->head allocation, and eth_get_headlen for larger packets improving performance by about 10% in my tests. 3. For VXLAN packets it allows the full header to be in skb->data which improves the performance by as much as 30% in some of my tests. Signed-off-by: Alexander Duyck Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 49 ++++++++++++++++++++++++++- 1 file changed, 48 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index 7c696b3..2a10365 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -1896,7 +1896,7 @@ static bool ixgbe_cleanup_headers(struct ixgbe_ring *rx_ring, } /* place header in linear portion of buffer */ - if (skb_is_nonlinear(skb)) + if (!skb_headlen(skb)) ixgbe_pull_tail(rx_ring, skb); #ifdef IXGBE_FCOE @@ -2125,6 +2125,49 @@ static struct sk_buff *ixgbe_construct_skb(struct ixgbe_ring *rx_ring, return skb; } +static struct sk_buff *ixgbe_build_skb(struct ixgbe_ring *rx_ring, + struct ixgbe_rx_buffer *rx_buffer, + union ixgbe_adv_rx_desc *rx_desc, + unsigned int size) +{ + void *va = page_address(rx_buffer->page) + rx_buffer->page_offset; +#if (PAGE_SIZE < 8192) + unsigned int truesize = ixgbe_rx_pg_size(rx_ring) / 2; +#else + unsigned int truesize = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) + + SKB_DATA_ALIGN(IXGBE_SKB_PAD + size); +#endif + struct sk_buff *skb; + + /* prefetch first cache line of first page */ + prefetch(va); +#if L1_CACHE_BYTES < 128 + prefetch(va + L1_CACHE_BYTES); +#endif + + /* build an skb to around the page buffer */ + skb = build_skb(va - IXGBE_SKB_PAD, truesize); + if (unlikely(!skb)) + return NULL; + + /* update pointers within the skb to store the data */ + skb_reserve(skb, IXGBE_SKB_PAD); + __skb_put(skb, size); + + /* record DMA address if this is the start of a chain of buffers */ + if (!ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_EOP)) + IXGBE_CB(skb)->dma = rx_buffer->dma; + + /* update buffer offset */ +#if (PAGE_SIZE < 8192) + rx_buffer->page_offset ^= truesize; +#else + rx_buffer->page_offset += truesize; +#endif + + return skb; +} + /** * ixgbe_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf * @q_vector: structure containing interrupt and ring information @@ -2178,6 +2221,9 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, /* retrieve a buffer from the ring */ if (skb) ixgbe_add_rx_frag(rx_ring, rx_buffer, skb, size); + else if (ring_uses_build_skb(rx_ring)) + skb = ixgbe_build_skb(rx_ring, rx_buffer, + rx_desc, size); else skb = ixgbe_construct_skb(rx_ring, rx_buffer, rx_desc, size); @@ -3918,6 +3964,7 @@ static void ixgbe_set_rx_buffer_len(struct ixgbe_adapter *adapter) if (test_bit(__IXGBE_RX_FCOE, &rx_ring->state)) set_bit(__IXGBE_RX_3K_BUFFER, &rx_ring->state); + clear_bit(__IXGBE_RX_BUILD_SKB_ENABLED, &rx_ring->state); if (adapter->flags2 & IXGBE_FLAG2_RX_LEGACY) continue; -- 2.7.4