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Commit 724b6942 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
Browse files

sky2: no recycling 



Recycling turns out to be a bad idea!  For most use cases, the
packet can not be reused: TCP packets are cloned. Even for the ideal
case of forwarding, it hurts performance because of CPU ping/pong.
On a multi-core system forwarding of 64 byte packets is worse
much worse: recycling = 24% forwarded vs no recycling = 42% forwarded

Signed-off-by: default avatarStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6b84daca

drivers/net/sky2.c

+3 −13
Original line number Original line Diff line number Diff line
@@ -1177,7 +1177,6 @@ static void sky2_rx_clean(struct sky2_port *sky2) 
			re->skb = NULL;

			re->skb = NULL;

		}

		}

	}

	}

	skb_queue_purge(&sky2->rx_recycle);

}

}





/* Basic MII support */

/* Basic MII support */
@@ -1269,10 +1268,8 @@ static struct sk_buff *sky2_rx_alloc(struct sky2_port *sky2) 
	struct sk_buff *skb;

	struct sk_buff *skb;

	int i;

	int i;





	skb = __skb_dequeue(&sky2->rx_recycle);

	skb = netdev_alloc_skb(sky2->netdev,

	if (!skb)

			       sky2->rx_data_size + sky2_rx_pad(sky2->hw));

		skb = netdev_alloc_skb(sky2->netdev, sky2->rx_data_size

				       + sky2_rx_pad(sky2->hw));

	if (!skb)

	if (!skb)

		goto nomem;

		goto nomem;
@@ -1364,8 +1361,6 @@ static int sky2_rx_start(struct sky2_port *sky2) 




	sky2->rx_data_size = size;

	sky2->rx_data_size = size;





	skb_queue_head_init(&sky2->rx_recycle);



	/* Fill Rx ring */

	/* Fill Rx ring */

	for (i = 0; i < sky2->rx_pending; i++) {

	for (i = 0; i < sky2->rx_pending; i++) {

		re = sky2->rx_ring + i;

		re = sky2->rx_ring + i;
@@ -1776,11 +1771,6 @@ static void sky2_tx_complete(struct sky2_port *sky2, u16 done) 
			dev->stats.tx_packets++;

			dev->stats.tx_packets++;

			dev->stats.tx_bytes += skb->len;

			dev->stats.tx_bytes += skb->len;





			if (skb_queue_len(&sky2->rx_recycle) < sky2->rx_pending

			    && skb_recycle_check(skb, sky2->rx_data_size

						 + sky2_rx_pad(sky2->hw)))

				__skb_queue_head(&sky2->rx_recycle, skb);

			else

			dev_kfree_skb_any(skb);

			dev_kfree_skb_any(skb);





			sky2->tx_next = RING_NEXT(idx, sky2->tx_ring_size);

			sky2->tx_next = RING_NEXT(idx, sky2->tx_ring_size);

drivers/net/sky2.h

+0 −1
Original line number Original line Diff line number Diff line
@@ -2032,7 +2032,6 @@ struct sky2_port { 
	u16		     rx_pending;

	u16		     rx_pending;

	u16		     rx_data_size;

	u16		     rx_data_size;

	u16		     rx_nfrags;

	u16		     rx_nfrags;

	struct sk_buff_head  rx_recycle;





#ifdef SKY2_VLAN_TAG_USED

#ifdef SKY2_VLAN_TAG_USED

	u16		     rx_tag;

	u16		     rx_tag;