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| author | Sowmini Varadhan <sowmini.varadhan@oracle.com> | 2014-08-12 10:27:24 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-08-13 20:04:46 -0700 |
| commit | 1f6394e382f137f07136182c591ca8a7eeba6a06 (patch) | |
| tree | 4271803a31d0e1a584709ac2c6bcd9035eaadf12 | |
| parent | 8356f9d564ed3da4f98e8c44cbd9f397ff9c49a5 (diff) | |
| download | blackbird-op-linux-1f6394e382f137f07136182c591ca8a7eeba6a06.tar.gz blackbird-op-linux-1f6394e382f137f07136182c591ca8a7eeba6a06.zip | |
sunvnet: Do not ask for an ACK for every dring transmit
No need to ask for an ack with every vnet_start_xmit()- the single
ACK with DRING_STOPPED is sufficient for the protocol, and we free
the sk_buff in vnet_start_xmit itself, so we dont need an ACK back.
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Raghuram Kothakota <raghuram.kothakota@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/ethernet/sun/sunvnet.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c index d813bfb1a847..238434dcfe02 100644 --- a/drivers/net/ethernet/sun/sunvnet.c +++ b/drivers/net/ethernet/sun/sunvnet.c @@ -691,7 +691,15 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev) memset(tx_buf+VNET_PACKET_SKIP+skb->len, 0, len - skb->len); } - d->hdr.ack = VIO_ACK_ENABLE; + /* We don't rely on the ACKs to free the skb in vnet_start_xmit(), + * thus it is safe to not set VIO_ACK_ENABLE for each transmission: + * the protocol itself does not require it as long as the peer + * sends a VIO_SUBTYPE_ACK for VIO_DRING_STOPPED. + * + * An ACK for every packet in the ring is expensive as the + * sending of LDC messages is slow and affects performance. + */ + d->hdr.ack = VIO_ACK_DISABLE; d->size = len; d->ncookies = port->tx_bufs[dr->prod].ncookies; for (i = 0; i < d->ncookies; i++) |
