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Commit 24bff091 authored by Emil Tantilov's avatar Emil Tantilov Committed by Jeff Kirsher
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ixgbevf: use length to determine if descriptor is done 



Based on:
commit 7ec0116c ("igb: Use length to determine if descriptor is done")

This change makes it so that we use the length of the packet instead of the
DD status bit to determine if a new descriptor is ready to be processed.
The obvious advantage is that it cuts down on reads as we don't really even
need the DD bit if going from a 0 to a non-zero value on size is enough to
inform us that the packet has been completed.

In addition we only reset the Rx descriptor length for descriptor zero when
resetting a ring instead of having to do a memset with 0 over the entire
ring. By doing this we can save some time on initialization.

Signed-off-by: default avatarEmil Tantilov <emil.s.tantilov@intel.com>
Tested-by: default avatarKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 68b6ff58

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

+8 −6
Original line number Original line Diff line number Diff line
@@ -653,8 +653,8 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring, 
			i -= rx_ring->count;

			i -= rx_ring->count;

		}

		}





		/* clear the hdr_addr for the next_to_use descriptor */

		/* clear the length for the next_to_use descriptor */

		rx_desc->read.hdr_addr = 0;

		rx_desc->wb.upper.length = 0;





		cleaned_count--;

		cleaned_count--;

	} while (cleaned_count);

	} while (cleaned_count);
@@ -938,7 +938,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector, 




		rx_desc = IXGBEVF_RX_DESC(rx_ring, rx_ring->next_to_clean);

		rx_desc = IXGBEVF_RX_DESC(rx_ring, rx_ring->next_to_clean);





		if (!ixgbevf_test_staterr(rx_desc, IXGBE_RXD_STAT_DD))

		if (!rx_desc->wb.upper.length)

			break;

			break;





		/* This memory barrier is needed to keep us from reading

		/* This memory barrier is needed to keep us from reading
@@ -1729,6 +1729,7 @@ static void ixgbevf_configure_rx_ring(struct ixgbevf_adapter *adapter, 
				      struct ixgbevf_ring *ring)

				      struct ixgbevf_ring *ring)

{

{

	struct ixgbe_hw *hw = &adapter->hw;

	struct ixgbe_hw *hw = &adapter->hw;

	union ixgbe_adv_rx_desc *rx_desc;

	u64 rdba = ring->dma;

	u64 rdba = ring->dma;

	u32 rxdctl;

	u32 rxdctl;

	u8 reg_idx = ring->reg_idx;

	u8 reg_idx = ring->reg_idx;
@@ -1757,6 +1758,10 @@ static void ixgbevf_configure_rx_ring(struct ixgbevf_adapter *adapter, 
	IXGBE_WRITE_REG(hw, IXGBE_VFRDT(reg_idx), 0);

	IXGBE_WRITE_REG(hw, IXGBE_VFRDT(reg_idx), 0);

	ring->tail = adapter->io_addr + IXGBE_VFRDT(reg_idx);

	ring->tail = adapter->io_addr + IXGBE_VFRDT(reg_idx);





	/* initialize Rx descriptor 0 */

	rx_desc = IXGBEVF_RX_DESC(ring, 0);

	rx_desc->wb.upper.length = 0;



	/* reset ntu and ntc to place SW in sync with hardwdare */

	/* reset ntu and ntc to place SW in sync with hardwdare */

	ring->next_to_clean = 0;

	ring->next_to_clean = 0;

	ring->next_to_use = 0;

	ring->next_to_use = 0;
@@ -2141,9 +2146,6 @@ static void ixgbevf_clean_rx_ring(struct ixgbevf_ring *rx_ring) 




	size = sizeof(struct ixgbevf_rx_buffer) * rx_ring->count;

	size = sizeof(struct ixgbevf_rx_buffer) * rx_ring->count;

	memset(rx_ring->rx_buffer_info, 0, size);

	memset(rx_ring->rx_buffer_info, 0, size);



	/* Zero out the descriptor ring */

	memset(rx_ring->desc, 0, rx_ring->size);

}

}





/**

/**