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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: Anton Blanchard <anton@samba.org>
Signed-off-by: Santiago Leon <santil@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Santiago Leon 2010-09-03 18:28:41 +00:00 committed by David S. Miller
parent 6e8ab30ec6
commit 0c26b6775f
1 changed files with 21 additions and 0 deletions
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21
drivers/net/ibmveth.c
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@ -127,6 +127,10 @@ module_param(rx_copybreak, uint, 0644);
MODULE_PARM_DESC(rx_copybreak,
"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 {
char name[ETH_GSTRING_LEN];
int offset;
@ -234,6 +238,14 @@ static int ibmveth_alloc_buffer_pool(struct ibmveth_buff_pool *pool)
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
* 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.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);
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->data + offset,
length);
if (rx_flush)
ibmveth_flush_buffer(skb->data,
length + offset);
skb = new_skb;
ibmveth_rxq_recycle_buffer(adapter);
} else {