[TIPC]: Optimize stream send routine to avoid fragmentation

This patch enhances TIPC's stream socket send routine so that
it avoids transmitting data in chunks that require fragmentation
and reassembly, thereby improving performance at both the
sending and receiving ends of the connection.

The "maximum packet size" hint that records MTU info allows
the socket to decide how big a chunk it should send; in the
event that the hint has become stale, fragmentation may still
occur, but the data will be passed correctly and the hint will
be updated in time for the following send.  Note: The 66060 byte
pseudo-MTU used for intra-node connections requires the send
routine to perform an additional check to ensure it does not
exceed TIPC"s limit of 66000 bytes of user data per chunk.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Jon Paul Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/include/net/tipc/tipc_port.h b/include/net/tipc/tipc_port.h
index 333bba6dc522..cfc4ba46de8f 100644
--- a/include/net/tipc/tipc_port.h
+++ b/include/net/tipc/tipc_port.h
@@ -1,8 +1,8 @@
 /*
  * include/net/tipc/tipc_port.h: Include file for privileged access to TIPC ports
  * 
- * Copyright (c) 1994-2006, Ericsson AB
- * Copyright (c) 2005, Wind River Systems
+ * Copyright (c) 1994-2007, Ericsson AB
+ * Copyright (c) 2005-2007, Wind River Systems
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -55,6 +55,7 @@
  * @conn_unacked: number of unacknowledged messages received from peer port
  * @published: non-zero if port has one or more associated names
  * @congested: non-zero if cannot send because of link or port congestion
+ * @max_pkt: maximum packet size "hint" used when building messages sent by port
  * @ref: unique reference to port in TIPC object registry
  * @phdr: preformatted message header used when sending messages
  */
@@ -68,6 +69,7 @@ struct tipc_port {
         u32 conn_unacked;
         int published;
         u32 congested;
+        u32 max_pkt;
         u32 ref;
         struct tipc_msg phdr;
 };