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authorPriyaranjan Jha <priyarjha@google.com>2020-07-16 12:12:35 -0700
committerDavid S. Miller <davem@davemloft.net>2020-07-17 12:54:30 -0700
commite3a5a1e8b6548f5d37328e2d3571edc5c9e6d7c0 (patch)
tree9d7078789cda963aeeeb97f5185b2efcd281c4b1 /net/ipv4/proc.c
parenta71d77e6be1e29ec809cc7c85d9594e7769406cd (diff)
downloadlinux-e3a5a1e8b6548f5d37328e2d3571edc5c9e6d7c0.tar.bz2
tcp: add SNMP counter for no. of duplicate segments reported by DSACK
There are two existing SNMP counters, TCPDSACKRecv and TCPDSACKOfoRecv, which are incremented depending on whether the DSACKed range is below the cumulative ACK sequence number or not. Unfortunately, these both implicitly assume each DSACK covers only one segment. This makes these counters unusable for estimating spurious retransmit rates, or real/non-spurious loss rate. This patch introduces a new SNMP counter, TCPDSACKRecvSegs, which tracks the estimated number of duplicate segments based on: (DSACKed sequence range) / MSS. This counter is usable for estimating spurious retransmit rates, or real/non-spurious loss rate. Signed-off-by: Priyaranjan Jha <priyarjha@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/proc.c')
-rw-r--r--net/ipv4/proc.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 75545a829a2b..1074df726ec0 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -292,6 +292,7 @@ static const struct snmp_mib snmp4_net_list[] = {
SNMP_MIB_ITEM("TCPFastOpenPassiveAltKey", LINUX_MIB_TCPFASTOPENPASSIVEALTKEY),
SNMP_MIB_ITEM("TcpTimeoutRehash", LINUX_MIB_TCPTIMEOUTREHASH),
SNMP_MIB_ITEM("TcpDuplicateDataRehash", LINUX_MIB_TCPDUPLICATEDATAREHASH),
+ SNMP_MIB_ITEM("TCPDSACKRecvSegs", LINUX_MIB_TCPDSACKRECVSEGS),
SNMP_MIB_SENTINEL
};