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Commit 0c26b677 authored by Santiago Leon's avatar Santiago Leon Committed by David S. Miller
Browse files

ibmveth: Add optional flush of rx buffer 



On some machines we can improve the bandwidth by ensuring rx buffers are
not in the cache. Add a module option that is disabled by default that flushes
rx buffers on insertion.

Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarSantiago Leon <santil@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6e8ab30e

drivers/net/ibmveth.c

+21 −0
Original line number Original line Diff line number Diff line
@@ -127,6 +127,10 @@ module_param(rx_copybreak, uint, 0644); 
MODULE_PARM_DESC(rx_copybreak,

MODULE_PARM_DESC(rx_copybreak,

	"Maximum size of packet that is copied to a new buffer on receive");

	"Maximum size of packet that is copied to a new buffer on receive");





static unsigned int rx_flush __read_mostly = 0;

module_param(rx_flush, uint, 0644);

MODULE_PARM_DESC(rx_flush, "Flush receive buffers before use");



struct ibmveth_stat {

struct ibmveth_stat {

	char name[ETH_GSTRING_LEN];

	char name[ETH_GSTRING_LEN];

	int offset;

	int offset;
@@ -234,6 +238,14 @@ static int ibmveth_alloc_buffer_pool(struct ibmveth_buff_pool *pool) 
	return 0;

	return 0;

}

}





static inline void ibmveth_flush_buffer(void *addr, unsigned long length)

{

	unsigned long offset;



	for (offset = 0; offset < length; offset += SMP_CACHE_BYTES)

		asm("dcbfl %0,%1" :: "b" (addr), "r" (offset));

}



/* replenish the buffers for a pool.  note that we don't need to

/* replenish the buffers for a pool.  note that we don't need to

 * skb_reserve these since they are used for incoming...

 * skb_reserve these since they are used for incoming...

 */

 */
@@ -286,6 +298,12 @@ static void ibmveth_replenish_buffer_pool(struct ibmveth_adapter *adapter, struc 
		desc.fields.flags_len = IBMVETH_BUF_VALID | pool->buff_size;

		desc.fields.flags_len = IBMVETH_BUF_VALID | pool->buff_size;

		desc.fields.address = dma_addr;

		desc.fields.address = dma_addr;





		if (rx_flush) {

			unsigned int len = min(pool->buff_size,

						adapter->netdev->mtu +

						IBMVETH_BUFF_OH);

			ibmveth_flush_buffer(skb->data, len);

		}

		lpar_rc = h_add_logical_lan_buffer(adapter->vdev->unit_address, desc.desc);

		lpar_rc = h_add_logical_lan_buffer(adapter->vdev->unit_address, desc.desc);





		if (lpar_rc != H_SUCCESS)

		if (lpar_rc != H_SUCCESS)
@@ -1095,6 +1113,9 @@ static int ibmveth_poll(struct napi_struct *napi, int budget) 
				skb_copy_to_linear_data(new_skb,

				skb_copy_to_linear_data(new_skb,

							skb->data + offset,

							skb->data + offset,

							length);

							length);

				if (rx_flush)

					ibmveth_flush_buffer(skb->data,

						length + offset);

				skb = new_skb;

				skb = new_skb;

				ibmveth_rxq_recycle_buffer(adapter);

				ibmveth_rxq_recycle_buffer(adapter);

			} else {

			} else {