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ixgbe: 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.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Alexander Duyck 2017-01-17 08:36:28 -08:00 committed by Jeff Kirsher
parent 4f4542bfb3
commit c3630cc40b
2 changed files with 9 additions and 7 deletions
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2
drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
View File

@ -1868,7 +1868,7 @@ static u16 ixgbe_clean_test_rings(struct ixgbe_ring *rx_ring,
tx_ntc = tx_ring->next_to_clean;
rx_desc = IXGBE_RX_DESC(rx_ring, rx_ntc);
while (ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_DD)) {
while (rx_desc->wb.upper.length) {
/* check Rx buffer */
rx_buffer = &rx_ring->rx_buffer_info[rx_ntc];

14
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
View File

@ -1640,8 +1640,8 @@ void ixgbe_alloc_rx_buffers(struct ixgbe_ring *rx_ring, u16 cleaned_count)
i -= rx_ring->count;
}
/* clear the status bits for the next_to_use descriptor */
rx_desc->wb.upper.status_error = 0;
/* clear the length for the next_to_use descriptor */
rx_desc->wb.upper.length = 0;
cleaned_count--;
} while (cleaned_count);
@ -2154,7 +2154,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
rx_desc = IXGBE_RX_DESC(rx_ring, rx_ring->next_to_clean);
if (!rx_desc->wb.upper.status_error)
if (!rx_desc->wb.upper.length)
break;
/* This memory barrier is needed to keep us from reading
@ -3698,6 +3698,7 @@ void ixgbe_configure_rx_ring(struct ixgbe_adapter *adapter,
struct ixgbe_ring *ring)
{
struct ixgbe_hw *hw = &adapter->hw;
union ixgbe_adv_rx_desc *rx_desc;
u64 rdba = ring->dma;
u32 rxdctl;
u8 reg_idx = ring->reg_idx;
@ -3732,6 +3733,10 @@ void ixgbe_configure_rx_ring(struct ixgbe_adapter *adapter,
rxdctl |= 0x080420;
}
/* initialize Rx descriptor 0 */
rx_desc = IXGBE_RX_DESC(ring, 0);
rx_desc->wb.upper.length = 0;
/* enable receive descriptor ring */
rxdctl |= IXGBE_RXDCTL_ENABLE;
IXGBE_WRITE_REG(hw, IXGBE_RXDCTL(reg_idx), rxdctl);
@ -4940,9 +4945,6 @@ static void ixgbe_clean_rx_ring(struct ixgbe_ring *rx_ring)
size = sizeof(struct ixgbe_rx_buffer) * rx_ring->count;
memset(rx_ring->rx_buffer_info, 0, size);
/* Zero out the descriptor ring */
memset(rx_ring->desc, 0, rx_ring->size);
rx_ring->next_to_alloc = 0;
rx_ring->next_to_clean = 0;
rx_ring->next_to_use = 0;