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Commit a3a8749d authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by David S. Miller
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ixgbe: bulk free SKBs during TX completion cleanup cycle 



There is an opportunity to bulk free SKBs during reclaiming of
resources after DMA transmit completes in ixgbe_clean_tx_irq.  Thus,
bulk freeing at this point does not introduce any added latency.

Simply use napi_consume_skb() which were recently introduced.  The
napi_budget parameter is needed by napi_consume_skb() to detect if it
is called from netpoll.

Benchmarking IPv4-forwarding, on CPU i7-4790K @4.2GHz (no turbo boost)
 Single CPU/flow numbers: before: 1982144 pps ->  after : 2064446 pps
 Improvement: +82302 pps, -20 nanosec, +4.1%
 (SLUB and GCC version 5.1.1 20150618 (Red Hat 5.1.1-4))

Joint work with Alexander Duyck.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 15fad714

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

+3 −3
Original line number Diff line number Diff line
@@ -1089,7 +1089,7 @@ static void ixgbe_tx_timeout_reset(struct ixgbe_adapter *adapter) 
 * @tx_ring: tx ring to clean

 **/

static bool ixgbe_clean_tx_irq(struct ixgbe_q_vector *q_vector,

			       struct ixgbe_ring *tx_ring)

			       struct ixgbe_ring *tx_ring, int napi_budget)

{

	struct ixgbe_adapter *adapter = q_vector->adapter;

	struct ixgbe_tx_buffer *tx_buffer;
@@ -1127,7 +1127,7 @@ static bool ixgbe_clean_tx_irq(struct ixgbe_q_vector *q_vector, 
		total_packets += tx_buffer->gso_segs;



		/* free the skb */

		dev_consume_skb_any(tx_buffer->skb);

		napi_consume_skb(tx_buffer->skb, napi_budget);



		/* unmap skb header data */

		dma_unmap_single(tx_ring->dev,
@@ -2784,7 +2784,7 @@ int ixgbe_poll(struct napi_struct *napi, int budget) 
#endif



	ixgbe_for_each_ring(ring, q_vector->tx)

		clean_complete &= !!ixgbe_clean_tx_irq(q_vector, ring);

		clean_complete &= !!ixgbe_clean_tx_irq(q_vector, ring, budget);



	/* Exit if we are called by netpoll or busy polling is active */

	if ((budget <= 0) || !ixgbe_qv_lock_napi(q_vector))