From 4f693b55c3d2d2239b8a0094b518a1e533cf75d5 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 27 Nov 2018 14:42:03 -0800 Subject: tcp: implement coalescing on backlog queue In case GRO is not as efficient as it should be or disabled, we might have a user thread trapped in __release_sock() while softirq handler flood packets up to the point we have to drop. This patch balances work done from user thread and softirq, to give more chances to __release_sock() to complete its work before new packets are added the the backlog. This also helps if we receive many ACK packets, since GRO does not aggregate them. This patch brings ~60% throughput increase on a receiver without GRO, but the spectacular gain is really on 1000x release_sock() latency reduction I have measured. Signed-off-by: Eric Dumazet Cc: Neal Cardwell Cc: Yuchung Cheng Acked-by: Neal Cardwell Signed-off-by: David S. Miller --- net/ipv4/proc.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/ipv4/proc.c') diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 70289682a670..c3610b37bb4c 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -219,6 +219,7 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPRenoRecoveryFail", LINUX_MIB_TCPRENORECOVERYFAIL), SNMP_MIB_ITEM("TCPSackRecoveryFail", LINUX_MIB_TCPSACKRECOVERYFAIL), SNMP_MIB_ITEM("TCPRcvCollapsed", LINUX_MIB_TCPRCVCOLLAPSED), + SNMP_MIB_ITEM("TCPBacklogCoalesce", LINUX_MIB_TCPBACKLOGCOALESCE), SNMP_MIB_ITEM("TCPDSACKOldSent", LINUX_MIB_TCPDSACKOLDSENT), SNMP_MIB_ITEM("TCPDSACKOfoSent", LINUX_MIB_TCPDSACKOFOSENT), SNMP_MIB_ITEM("TCPDSACKRecv", LINUX_MIB_TCPDSACKRECV), -- cgit v1.2.3