linux/net
Jon Maloy d3b09995ab tipc: eliminate more unnecessary nacks and retransmissions
When we increase the link tranmsit window we often observe the following
scenario:

1) A STATE message bypasses a sequence of traffic packets and arrives
   far ahead of those to the receiver. STATE messages contain a
   'peers_nxt_snt' field to indicate which was the last packet sent
   from the peer. This mechanism is intended as a last resort for the
   receiver to detect missing packets, e.g., during very low traffic
   when there is no packet flow to help early loss detection.
3) The receiving link compares the 'peer_nxt_snt' field to its own
   'rcv_nxt', finds that there is a gap, and immediately sends a
   NACK message back to the peer.
4) When this NACKs arrives at the sender, all the requested
   retransmissions are performed, since it is a first-time request.

Just like in the scenario described in the previous commit this leads
to many redundant retransmissions, with decreased throughput as a
consequence.

We fix this by adding two more conditions before we send a NACK in
this sitution. First, the deferred queue must be empty, so we cannot
assume that the potential packet loss has already been detected by
other means. Second, we check the 'peers_snd_nxt' field only in probe/
probe_reply messages, thus turning this into a true mechanism of last
resort as it was really meant to be.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-10 17:31:15 -08:00
..
6lowpan 6lowpan: no need to check return value of debugfs_create functions 2019-07-06 12:50:01 +02:00
9p 9p pull request for inclusion in 5.4 2019-09-27 15:10:34 -07:00
802 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
8021q net: remove unnecessary variables and callback 2019-10-24 14:53:49 -07:00
appletalk appletalk: enforce CAP_NET_RAW for raw sockets 2019-09-24 16:37:18 +02:00
atm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-22 16:27:24 -08:00
ax25 net: use helpers to change sk_ack_backlog 2019-11-06 16:14:48 -08:00
batman-adv batman-adv: Drop lockdep.h include for soft-interface.c 2019-11-03 08:30:58 +01:00
bluetooth compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
bpf bpf: Fix memory leak on object 'data' 2019-11-18 19:32:59 -08:00
bpfilter Kbuild updates for v5.3 2019-07-12 16:03:16 -07:00
bridge net: bridge: deny dev_set_mac_address() when unregistering 2019-12-03 11:21:20 -08:00
caif Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-02 13:54:56 -07:00
can can: j1939: warn if resources are still linked on destroy 2019-11-13 10:42:34 +01:00
ceph libceph, rbd, ceph: convert to use the new mount API 2019-11-27 22:28:37 +01:00
core inet: protect against too small mtu values. 2019-12-07 11:55:11 -08:00
dcb
dccp net: ipv6: add net argument to ip6_dst_lookup_flow 2019-12-04 12:27:12 -08:00
decnet net: use helpers to change sk_ack_backlog 2019-11-06 16:14:48 -08:00
dns_resolver Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
dsa net: phylink: rename mac_link_state() op to mac_pcs_get_state() 2019-11-23 16:13:39 -08:00
ethernet net: add annotations on hh->hh_len lockless accesses 2019-11-07 20:07:30 -08:00
hsr hsr: fix a NULL pointer dereference in hsr_dev_xmit() 2019-12-05 12:09:02 -08:00
ieee802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-02 13:54:56 -07:00
ife net: Fix Kconfig indentation 2019-09-26 08:56:17 +02:00
ipv4 net-tcp: Disable TCP ssthresh metrics cache by default 2019-12-09 20:17:48 -08:00
ipv6 net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup 2019-12-04 12:27:13 -08:00
iucv net/af_iucv: mark expected switch fall-throughs 2019-07-29 10:26:14 -07:00
kcm kcm: disable preemption in kcm_parse_func_strparser() 2019-09-27 10:27:14 +02:00
key Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-07-08 19:48:57 -07:00
l2tp net: ipv6: add net argument to ip6_dst_lookup_flow 2019-12-04 12:27:12 -08:00
l3mdev ipv6: convert major tx path to use RT6_LOOKUP_F_DST_NOREF 2019-06-23 13:24:17 -07:00
lapb
llc net: silence data-races on sk_backlog.tail 2019-11-06 21:35:34 -08:00
mac80211 Driver core patches for 5.5-rc1 2019-11-27 11:06:20 -08:00
mac802154
mpls net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup 2019-12-04 12:27:13 -08:00
ncsi net/ncsi: Disable global multicast filter 2019-09-19 18:04:40 -07:00
netfilter net: core: rename indirect block ingress cb function 2019-12-06 20:45:09 -08:00
netlabel netlabel: remove redundant assignment to pointer iter 2019-09-01 11:45:02 -07:00
netlink genetlink: do not parse attributes for families with zero maxattr 2019-10-13 11:20:03 -07:00
netrom net: core: add generic lockdep keys 2019-10-24 14:53:48 -07:00
nfc NFC: NCI: use new `delay` structure for SPI transfer delays 2019-12-04 17:00:58 -08:00
nsh treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
openvswitch net: Fixed updating of ethertype in skb_mpls_push() 2019-12-04 17:11:25 -08:00
packet packet: fix data-race in fanout_flow_is_huge() 2019-11-08 14:06:19 -08:00
phonet net: use skb_queue_empty_lockless() in poll() handlers 2019-10-28 13:33:41 -07:00
psample net: psample: fix skb_over_panic 2019-11-26 14:40:13 -08:00
qrtr net: qrtr: Simplify 'qrtr_tun_release()' 2019-10-30 17:58:23 -07:00
rds Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-16 21:51:42 -08:00
rfkill compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
rose net: use helpers to change sk_ack_backlog 2019-11-06 16:14:48 -08:00
rxrpc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2019-11-25 20:02:57 -08:00
sched net_sched: validate TCA_KIND attribute in tc_chain_tmplt_add() 2019-12-07 12:04:16 -08:00
sctp sctp: get netns from asoc and ep base 2019-12-09 20:14:01 -08:00
smc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-16 21:51:42 -08:00
strparser Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-22 08:59:24 -04:00
sunrpc This is a relatively quiet cycle for nfsd, mainly various bugfixes. 2019-12-07 16:56:00 -08:00
switchdev
tipc tipc: eliminate more unnecessary nacks and retransmissions 2019-12-10 17:31:15 -08:00
tls net/tls: Fix return values to avoid ENOTSUPP 2019-12-06 20:15:39 -08:00
unix compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
vmw_vsock - Support for new VMBus protocols (Andrea Parri). 2019-11-30 14:50:51 -08:00
wimax wimax: no need to check return value of debugfs_create functions 2019-08-10 15:25:47 -07:00
wireless Some relatively small changes: 2019-11-08 11:36:48 -08:00
x25 net: use helpers to change sk_ack_backlog 2019-11-06 16:14:48 -08:00
xdp xsk: Fix xsk_poll()'s return type 2019-11-24 16:58:44 -08:00
xfrm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2019-11-25 20:02:57 -08:00
Kconfig net: Fix Kconfig indentation, continued 2019-11-21 12:00:21 -08:00
Makefile
compat.c y2038: socket: use __kernel_old_timespec instead of timespec 2019-11-15 14:38:29 +01:00
socket.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-12-08 13:28:11 -08:00
sysctl_net.c