kernel_optimize_test/net/tipc
Allan Stephens 7a54d4a99d tipc: Major redesign of broadcast link ACK/NACK algorithms
Completely redesigns broadcast link ACK and NACK mechanisms to prevent
spurious retransmit requests in dual LAN networks, and to prevent the
broadcast link from stalling due to the failure of a receiving node to
acknowledge receiving a broadcast message or request its retransmission.

Note: These changes only impact the timing of when ACK and NACK messages
are sent, and not the basic broadcast link protocol itself, so inter-
operability with nodes using the "classic" algorithms is maintained.

The revised algorithms are as follows:

1) An explicit ACK message is still sent after receiving 16 in-sequence
messages, and implicit ACK information continues to be carried in other
unicast link message headers (including link state messages).  However,
the timing of explicit ACKs is now based on the receiving node's absolute
network address rather than its relative network address to ensure that
the failure of another node does not delay the ACK beyond its 16 message
target.

2) A NACK message is now typically sent only when a message gap persists
for two consecutive incoming link state messages; this ensures that a
suspected gap is not confirmed until both LANs in a dual LAN network have
had an opportunity to deliver the message, thereby preventing spurious NACKs.
A NACK message can also be generated by the arrival of a single link state
message, if the deferred queue is so big that the current message gap
cannot be the result of "normal" mis-ordering due to the use of dual LANs
(or one LAN using a bonded interface). Since link state messages typically
arrive at different nodes at different times the problem of multiple nodes
issuing identical NACKs simultaneously is inherently avoided.

3) Nodes continue to "peek" at NACK messages sent by other nodes. If
another node requests retransmission of a message gap suspected (but not
yet confirmed) by the peeking node, the peeking node forgets about the
gap and does not generate a duplicate retransmit request. (If the peeking
node subsequently fails to receive the lost message, later link state
messages will cause it to rediscover and confirm the gap and send another
NACK.)

4) Message gap "equality" is now determined by the start of the gap only.
This is sufficient to deal with the most common cases of message loss,
and eliminates the need for complex end of gap computations.

5) A peeking node no longer tries to determine whether it should send a
complementary NACK, since the most common cases of message loss don't
require it to be sent. Consequently, the node no longer examines the
"broadcast tag" field of a NACK message when peeking.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-02-06 16:59:18 -05:00
..
addr.c tipc: Eliminate configuration for maximum number of cluster nodes 2011-03-13 16:35:17 -04:00
addr.h tipc: make zone/cluster mask constants a define 2011-05-10 16:03:54 -04:00
bcast.c tipc: Major redesign of broadcast link ACK/NACK algorithms 2012-02-06 16:59:18 -05:00
bcast.h tipc: Major redesign of broadcast link ACK/NACK algorithms 2012-02-06 16:59:18 -05:00
bearer.c tipc: rename struct bearer_name to struct tipc_bearer_names 2011-12-29 21:53:30 -05:00
bearer.h tipc: rename struct bearer_name to struct tipc_bearer_names 2011-12-29 21:53:30 -05:00
config.c tipc: Revise comment justifying release of configuration spinlock 2011-12-27 11:33:40 -05:00
config.h tipc: Remove unused link event tracking code 2011-09-17 22:55:15 -04:00
core.c tipc: Minor optimization to deactivation of Ethernet media suppot 2011-12-27 11:33:41 -05:00
core.h atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
discover.c tipc: rename struct link* to struct tipc_link* 2011-12-29 21:53:30 -05:00
discover.h tipc: rename struct link* to struct tipc_link* 2011-12-29 21:53:30 -05:00
eth_media.c tipc: rename struct media to struct tipc_media 2011-12-29 21:53:29 -05:00
handler.c tipc: remove zeroing assignments to static global variables 2011-01-01 13:57:57 -08:00
Kconfig tipc: Eliminate configuration for maximum number of cluster nodes 2011-03-13 16:35:17 -04:00
link.c tipc: Major redesign of broadcast link ACK/NACK algorithms 2012-02-06 16:59:18 -05:00
link.h tipc: rename struct link* to struct tipc_link* 2011-12-29 21:53:30 -05:00
log.c tipc: Finish streamlining of debugging code 2011-01-01 13:57:54 -08:00
log.h tipc: update log.h re-include protection to reflect new name 2011-01-01 14:56:18 -08:00
Makefile tipc: rename dbg.[ch] to log.[ch] 2011-01-01 13:57:51 -08:00
msg.c tipc: Hide media-specific addressing details from generic bearer code 2011-12-27 11:33:36 -05:00
msg.h tipc: Hide media-specific addressing details from generic bearer code 2011-12-27 11:33:36 -05:00
name_distr.c tipc: rename struct link* to struct tipc_link* 2011-12-29 21:53:30 -05:00
name_distr.h
name_table.c tipc: rename struct subscription to struct tipc_subscription 2011-12-29 21:53:29 -05:00
name_table.h tipc: rename struct subscription to struct tipc_subscription 2011-12-29 21:53:29 -05:00
net.c tipc: Eliminate dynamic allocation of broadcast link data structures 2011-12-27 11:33:47 -05:00
net.h tipc: manually inline net_start/stop, make assoc. vars static 2011-03-13 16:35:17 -04:00
netlink.c genetlink: make netns aware 2009-07-12 14:03:27 -07:00
node_subscr.c tipc: Cosmetic changes to node subscription code 2011-03-13 16:35:16 -04:00
node_subscr.h tipc: Cosmetic changes to node subscription code 2011-03-13 16:35:16 -04:00
node.c tipc: Major redesign of broadcast link ACK/NACK algorithms 2012-02-06 16:59:18 -05:00
node.h tipc: Major redesign of broadcast link ACK/NACK algorithms 2012-02-06 16:59:18 -05:00
port.c tipc: rename struct port_list to struct tipc_port_list 2011-12-29 21:53:29 -05:00
port.h tipc: rename struct port_list to struct tipc_port_list 2011-12-29 21:53:29 -05:00
ref.c net: two vzalloc() cleanups 2011-12-19 16:01:38 -05:00
ref.h tipc: cleanup function namespace 2010-10-16 11:13:24 -07:00
socket.c tipc: Enable use by containers having their own network namespace 2011-12-27 11:13:05 -05:00
subscr.c tipc: rename struct subscriber to struct tipc_subscriber 2011-12-29 21:53:30 -05:00
subscr.h tipc: rename struct subscription to struct tipc_subscription 2011-12-29 21:53:29 -05:00