Under "heavy" RX load, the driver cannot handle the descriptors fast
enough. In detail, when a descriptor is consumed, its used flag is
cleared and once the RX budget is consumed all descriptors with a
cleared used flag are prepared to receive more data. Under load though,
the HW may constantly receive more data and use those descriptors with a
cleared used flag before they are actually prepared for next usage.
The head and tail pointers into the RX-ring should always be valid and
we can omit clearing and checking of the used flag.
Signed-off-by: Soren Brinkmann <soren.brinkm...@xilinx.com>
---
---
drivers/net/ethernet/cadence/macb.c | 10 ----------
1 file changed, 10 deletions(-)
diff --git a/drivers/net/ethernet/cadence/macb.c
b/drivers/net/ethernet/cadence/macb.c
index 3e13aa31548a..e9daa072ebb4 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -599,25 +599,16 @@ static void gem_rx_refill(struct macb *bp)
{
unsigned int entry;
struct sk_buff *skb;
- struct macb_dma_desc *desc;
dma_addr_t paddr;
while (CIRC_SPACE(bp->rx_prepared_head, bp->rx_tail, RX_RING_SIZE) > 0)
{
- u32 addr, ctrl;
-
entry = macb_rx_ring_wrap(bp->rx_prepared_head);
- desc = &bp->rx_ring[entry];
/* Make hw descriptor updates visible to CPU */
rmb();
- addr = desc->addr;
- ctrl = desc->ctrl;
bp->rx_prepared_head++;
- if ((addr & MACB_BIT(RX_USED)))
- continue;
-
if (bp->rx_skbuff[entry] == NULL) {
/* allocate sk_buff for this free entry in ring */
skb = netdev_alloc_skb(bp->dev, bp->rx_buffer_size);
@@ -698,7 +689,6 @@ static int gem_rx(struct macb *bp, int budget)
if (!(addr & MACB_BIT(RX_USED)))
break;
- desc->addr &= ~MACB_BIT(RX_USED);
bp->rx_tail++;
count++;
--
1.9.2.1.g06c4abd
--
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