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linux-next/net/tipc/link.h
Jon Maloy 16ad3f4022 tipc: introduce variable window congestion control
We introduce a simple variable window congestion control for links.
The algorithm is inspired by the Reno algorithm, covering both 'slow
start', 'congestion avoidance', and 'fast recovery' modes.

- We introduce hard lower and upper window limits per link, still
  different and configurable per bearer type.

- We introduce a 'slow start theshold' variable, initially set to
  the maximum window size.

- We let a link start at the minimum congestion window, i.e. in slow
  start mode, and then let is grow rapidly (+1 per rceived ACK) until
  it reaches the slow start threshold and enters congestion avoidance
  mode.

- In congestion avoidance mode we increment the congestion window for
  each window-size number of acked packets, up to a possible maximum
  equal to the configured maximum window.

- For each non-duplicate NACK received, we drop back to fast recovery
  mode, by setting the both the slow start threshold to and the
  congestion window to (current_congestion_window / 2).

- If the timeout handler finds that the transmit queue has not moved
  since the previous timeout, it drops the link back to slow start
  and forces a probe containing the last sent sequence number to the
  sent to the peer, so that this can discover the stale situation.

This change does in reality have effect only on unicast ethernet
transport, as we have seen that there is no room whatsoever for
increasing the window max size for the UDP bearer.
For now, we also choose to keep the limits for the broadcast link
unchanged and equal.

This algorithm seems to give a 50-100% throughput improvement for
messages larger than MTU.

Suggested-by: Xin Long <lucien.xin@gmail.com>
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

157 lines
6.7 KiB
C

/*
* net/tipc/link.h: Include file for TIPC link code
*
* Copyright (c) 1995-2006, 2013-2014, Ericsson AB
* Copyright (c) 2004-2005, 2010-2011, Wind River Systems
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _TIPC_LINK_H
#define _TIPC_LINK_H
#include <net/genetlink.h>
#include "msg.h"
#include "node.h"
/* TIPC-specific error codes
*/
#define ELINKCONG EAGAIN /* link congestion <=> resource unavailable */
/* Link FSM events:
*/
enum {
LINK_ESTABLISH_EVT = 0xec1ab1e,
LINK_PEER_RESET_EVT = 0x9eed0e,
LINK_FAILURE_EVT = 0xfa110e,
LINK_RESET_EVT = 0x10ca1d0e,
LINK_FAILOVER_BEGIN_EVT = 0xfa110bee,
LINK_FAILOVER_END_EVT = 0xfa110ede,
LINK_SYNCH_BEGIN_EVT = 0xc1ccbee,
LINK_SYNCH_END_EVT = 0xc1ccede
};
/* Events returned from link at packet reception or at timeout
*/
enum {
TIPC_LINK_UP_EVT = 1,
TIPC_LINK_DOWN_EVT = (1 << 1),
TIPC_LINK_SND_STATE = (1 << 2)
};
/* Starting value for maximum packet size negotiation on unicast links
* (unless bearer MTU is less)
*/
#define MAX_PKT_DEFAULT 1500
bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
int tolerance, char net_plane, u32 mtu, int priority,
u32 min_win, u32 max_win, u32 session, u32 ownnode,
u32 peer, u8 *peer_id, u16 peer_caps,
struct tipc_link *bc_sndlink,
struct tipc_link *bc_rcvlink,
struct sk_buff_head *inputq,
struct sk_buff_head *namedq,
struct tipc_link **link);
bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer,
int mtu, u32 min_win, u32 max_win, u16 peer_caps,
struct sk_buff_head *inputq,
struct sk_buff_head *namedq,
struct tipc_link *bc_sndlink,
struct tipc_link **link);
void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
int mtyp, struct sk_buff_head *xmitq);
void tipc_link_create_dummy_tnl_msg(struct tipc_link *tnl,
struct sk_buff_head *xmitq);
void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
struct sk_buff_head *xmitq);
void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq);
int tipc_link_fsm_evt(struct tipc_link *l, int evt);
bool tipc_link_is_up(struct tipc_link *l);
bool tipc_link_peer_is_down(struct tipc_link *l);
bool tipc_link_is_reset(struct tipc_link *l);
bool tipc_link_is_establishing(struct tipc_link *l);
bool tipc_link_is_synching(struct tipc_link *l);
bool tipc_link_is_failingover(struct tipc_link *l);
bool tipc_link_is_blocked(struct tipc_link *l);
void tipc_link_set_active(struct tipc_link *l, bool active);
void tipc_link_reset(struct tipc_link *l);
void tipc_link_reset_stats(struct tipc_link *l);
int tipc_link_xmit(struct tipc_link *link, struct sk_buff_head *list,
struct sk_buff_head *xmitq);
struct sk_buff_head *tipc_link_inputq(struct tipc_link *l);
u16 tipc_link_rcv_nxt(struct tipc_link *l);
u16 tipc_link_acked(struct tipc_link *l);
u32 tipc_link_id(struct tipc_link *l);
char *tipc_link_name(struct tipc_link *l);
char *tipc_link_name_ext(struct tipc_link *l, char *buf);
u32 tipc_link_state(struct tipc_link *l);
char tipc_link_plane(struct tipc_link *l);
int tipc_link_prio(struct tipc_link *l);
int tipc_link_min_win(struct tipc_link *l);
int tipc_link_max_win(struct tipc_link *l);
void tipc_link_update_caps(struct tipc_link *l, u16 capabilities);
bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr);
unsigned long tipc_link_tolerance(struct tipc_link *l);
void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
struct sk_buff_head *xmitq);
void tipc_link_set_prio(struct tipc_link *l, u32 prio,
struct sk_buff_head *xmitq);
void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit);
void tipc_link_set_queue_limits(struct tipc_link *l, u32 min_win, u32 max_win);
int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
struct tipc_link *link, int nlflags);
int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[]);
int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq);
int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
struct sk_buff_head *xmitq);
int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq);
void tipc_link_add_bc_peer(struct tipc_link *snd_l,
struct tipc_link *uc_l,
struct sk_buff_head *xmitq);
void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
struct tipc_link *rcv_l,
struct sk_buff_head *xmitq);
int tipc_link_bc_peers(struct tipc_link *l);
void tipc_link_set_mtu(struct tipc_link *l, int mtu);
int tipc_link_mtu(struct tipc_link *l);
int tipc_link_mss(struct tipc_link *l);
void tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked,
struct sk_buff_head *xmitq);
void tipc_link_build_bc_sync_msg(struct tipc_link *l,
struct sk_buff_head *xmitq);
void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr);
int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
struct sk_buff_head *xmitq);
int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
struct sk_buff_head *xmitq);
bool tipc_link_too_silent(struct tipc_link *l);
#endif