tcp: optimize newreno cong ack handler
Type: improvement
Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I196ee5f4630cec637245493f370b5f83a939fe44
diff --git a/src/vnet/tcp/tcp_newreno.c b/src/vnet/tcp/tcp_newreno.c
index 39035ba..8c7e77f 100644
--- a/src/vnet/tcp/tcp_newreno.c
+++ b/src/vnet/tcp/tcp_newreno.c
@@ -62,30 +62,31 @@
newreno_rcv_cong_ack (tcp_connection_t * tc, tcp_cc_ack_t ack_type,
tcp_rate_sample_t * rs)
{
+ /* With sacks prr controls the data in flight post congestion */
+ if (PREDICT_TRUE (tcp_opts_sack_permitted (tc)))
+ return;
+
if (ack_type == TCP_CC_DUPACK)
{
- if (!tcp_opts_sack_permitted (tc))
- tc->cwnd += tc->snd_mss;
+ tc->cwnd += tc->snd_mss;
}
else if (ack_type == TCP_CC_PARTIALACK)
{
- /* RFC 6582 Sec. 3.2 */
- if (!tcp_opts_sack_permitted (&tc->rcv_opts))
- {
- /* Deflate the congestion window by the amount of new data
- * acknowledged by the Cumulative Acknowledgment field.
- * If the partial ACK acknowledges at least one SMSS of new data,
- * then add back SMSS bytes to the congestion window. This
- * artificially inflates the congestion window in order to reflect
- * the additional segment that has left the network. This "partial
- * window deflation" attempts to ensure that, when fast recovery
- * eventually ends, approximately ssthresh amount of data will be
- * outstanding in the network.*/
- tc->cwnd = (tc->cwnd > tc->bytes_acked + tc->snd_mss) ?
- tc->cwnd - tc->bytes_acked : tc->snd_mss;
- if (tc->bytes_acked > tc->snd_mss)
- tc->cwnd += tc->snd_mss;
- }
+ /* RFC 6582 Sec. 3.2
+ * Deflate the congestion window by the amount of new data
+ * acknowledged by the Cumulative Acknowledgment field.
+ * If the partial ACK acknowledges at least one SMSS of new data,
+ * then add back SMSS bytes to the congestion window. This
+ * artificially inflates the congestion window in order to reflect
+ * the additional segment that has left the network. This "partial
+ * window deflation" attempts to ensure that, when fast recovery
+ * eventually ends, approximately ssthresh amount of data will be
+ * outstanding in the network. */
+ tc->cwnd = (tc->cwnd > tc->bytes_acked + tc->snd_mss) ?
+ tc->cwnd - tc->bytes_acked :
+ tc->snd_mss;
+ if (tc->bytes_acked > tc->snd_mss)
+ tc->cwnd += tc->snd_mss;
}
}