On some platforms, syncing a buffer for DMA is expensive. Rather than
sync the whole 2K receive buffer, only synchronise the length of the
frame, which will typically be the MTU, or a much smaller TCP ACK.
For an IMX6Q, this gives around 6% increased TCP receive performance,
which is cache operations bound and reduces CPU load for TCP transmit.
Signed-off-by: Andrew Lunn <and...@lunn.ch>
---
v2:
Christmas tree the local variables
Pass size into igb_add_rx_frag() rather than repeating the endiness swap.
---
drivers/net/ethernet/intel/igb/igb_main.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c
b/drivers/net/ethernet/intel/igb/igb_main.c
index 0a289dda604a..8fa9e6e8c3b0 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6856,12 +6856,12 @@ static bool igb_can_reuse_rx_page(struct igb_rx_buffer
*rx_buffer,
**/
static bool igb_add_rx_frag(struct igb_ring *rx_ring,
struct igb_rx_buffer *rx_buffer,
+ unsigned int size,
union e1000_adv_rx_desc *rx_desc,
struct sk_buff *skb)
{
struct page *page = rx_buffer->page;
unsigned char *va = page_address(page) + rx_buffer->page_offset;
- unsigned int size = le16_to_cpu(rx_desc->wb.upper.length);
#if (PAGE_SIZE < 8192)
unsigned int truesize = IGB_RX_BUFSZ;
#else
@@ -6913,6 +6913,7 @@ static struct sk_buff *igb_fetch_rx_buffer(struct
igb_ring *rx_ring,
union e1000_adv_rx_desc *rx_desc,
struct sk_buff *skb)
{
+ unsigned int size = le16_to_cpu(rx_desc->wb.upper.length);
struct igb_rx_buffer *rx_buffer;
struct page *page;
@@ -6948,11 +6949,11 @@ static struct sk_buff *igb_fetch_rx_buffer(struct
igb_ring *rx_ring,
dma_sync_single_range_for_cpu(rx_ring->dev,
rx_buffer->dma,
rx_buffer->page_offset,
- IGB_RX_BUFSZ,
+ size,
DMA_FROM_DEVICE);
/* pull page into skb */
- if (igb_add_rx_frag(rx_ring, rx_buffer, rx_desc, skb)) {
+ if (igb_add_rx_frag(rx_ring, rx_buffer, size, rx_desc, skb)) {
/* hand second half of page back to the ring */
igb_reuse_rx_page(rx_ring, rx_buffer);
} else {
--
2.8.1
