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>
diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c
index d8a8984..1685e23 100644
--- a/drivers/net/ibmveth.c
+++ b/drivers/net/ibmveth.c
@@ -127,6 +127,10 @@
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 @@
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 @@
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 @@
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 {