sunvnet: Avoid sending superfluous LDC messages.
authorSowmini Varadhan <sowmini.varadhan@oracle.com>
Thu, 11 Sep 2014 13:57:22 +0000 (09:57 -0400)
committerDavid S. Miller <davem@davemloft.net>
Fri, 12 Sep 2014 22:19:08 +0000 (18:19 -0400)
commitd1015645dd535bbf10e52a3ef6d02ee0c3e0b267
treecbd8c73222b92fbef933b7cb95ff38fcd81d55ab
parentc706471b2601d1c9058e7b866db77f6eb7dd37af
sunvnet: Avoid sending superfluous LDC messages.

When sending out a burst of packets across multiple descriptors,
it is sufficient to send one LDC "start" trigger for
the first descriptor, so do not send an LDC "start" for every
pass through vnet_start_xmit. Similarly, it is sufficient to send
one "DRING_STOPPED" trigger for the last dring (and if that
fails, hold off and send the trigger later).

Optimizations to the number of LDC messages helps avoid
filling up the LDC channel with superfluous LDC messages
that risk triggering flow-control on the channel,
and also boosts performance.

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>
drivers/net/ethernet/sun/sunvnet.c
drivers/net/ethernet/sun/sunvnet.h