From 90f2f5318b3a5b0898fef0fec9b91376c7de7a2c Mon Sep 17 00:00:00 2001 From: Vlad Yasevich Date: Mon, 23 Nov 2009 15:53:57 -0500 Subject: sctp: Update SWS avaoidance receiver side algorithm We currently send window update SACKs every time we free up 1 PMTU worth of data. That a lot more SACKs then necessary. Instead, we'll now send back the actuall window every time we send a sack, and do window-update SACKs when a fraction of the receive buffer has been opened. The fraction is controlled with a sysctl. Signed-off-by: Vlad Yasevich --- include/net/sctp/constants.h | 4 ++++ include/net/sctp/structs.h | 6 ++++++ net/sctp/associola.c | 5 +++-- net/sctp/protocol.c | 3 +++ net/sctp/sm_sideeffect.c | 3 +-- net/sctp/sysctl.c | 13 +++++++++++++ 6 files changed, 30 insertions(+), 4 deletions(-) diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h index 58f714a..6390884 100644 --- a/include/net/sctp/constants.h +++ b/include/net/sctp/constants.h @@ -308,6 +308,10 @@ enum { SCTP_MAX_GABS = 16 }; #define SCTP_DEFAULT_MINWINDOW 1500 /* default minimum rwnd size */ #define SCTP_DEFAULT_MAXWINDOW 65535 /* default rwnd size */ +#define SCTP_DEFAULT_RWND_SHIFT 4 /* by default, update on 1/16 of + * rcvbuf, which is 1/8 of initial + * window + */ #define SCTP_DEFAULT_MAXSEGMENT 1500 /* MTU size, this is the limit * to which we will raise the P-MTU. */ diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index cd2e187..90876b6 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -231,6 +231,11 @@ extern struct sctp_globals { /* Flag to indicate whether computing and verifying checksum * is disabled. */ int checksum_disable; + + /* Threshold for rwnd update SACKS. Receive buffer shifted this many + * bits is an indicator of when to send and window update SACK. + */ + int rwnd_update_shift; } sctp_globals; #define sctp_rto_initial (sctp_globals.rto_initial) @@ -267,6 +272,7 @@ extern struct sctp_globals { #define sctp_prsctp_enable (sctp_globals.prsctp_enable) #define sctp_auth_enable (sctp_globals.auth_enable) #define sctp_checksum_disable (sctp_globals.checksum_disable) +#define sctp_rwnd_upd_shift (sctp_globals.rwnd_update_shift) /* SCTP Socket type: UDP or TCP style. */ typedef enum { diff --git a/net/sctp/associola.c b/net/sctp/associola.c index 8e755eb..37e9825 100644 --- a/net/sctp/associola.c +++ b/net/sctp/associola.c @@ -1383,8 +1383,9 @@ static inline int sctp_peer_needs_update(struct sctp_association *asoc) case SCTP_STATE_SHUTDOWN_RECEIVED: case SCTP_STATE_SHUTDOWN_SENT: if ((asoc->rwnd > asoc->a_rwnd) && - ((asoc->rwnd - asoc->a_rwnd) >= - min_t(__u32, (asoc->base.sk->sk_rcvbuf >> 1), asoc->pathmtu))) + ((asoc->rwnd - asoc->a_rwnd) >= max_t(__u32, + (asoc->base.sk->sk_rcvbuf >> sctp_rwnd_upd_shift), + asoc->pathmtu))) return 1; break; default: diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index 08ef203..a3c8988 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -1258,6 +1258,9 @@ SCTP_STATIC __init int sctp_init(void) /* Set SCOPE policy to enabled */ sctp_scope_policy = SCTP_SCOPE_POLICY_ENABLE; + /* Set the default rwnd update threshold */ + sctp_rwnd_upd_shift = SCTP_DEFAULT_RWND_SHIFT; + sctp_sysctl_register(); INIT_LIST_HEAD(&sctp_address_families); diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c index eda4fe7..8ae6709 100644 --- a/net/sctp/sm_sideeffect.c +++ b/net/sctp/sm_sideeffect.c @@ -217,8 +217,7 @@ static int sctp_gen_sack(struct sctp_association *asoc, int force, sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); } else { - if (asoc->a_rwnd > asoc->rwnd) - asoc->a_rwnd = asoc->rwnd; + asoc->a_rwnd = asoc->rwnd; sack = sctp_make_sack(asoc); if (!sack) goto nomem; diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c index ab7151d..ae03ded 100644 --- a/net/sctp/sysctl.c +++ b/net/sctp/sysctl.c @@ -52,6 +52,7 @@ static int int_max = INT_MAX; static int sack_timer_min = 1; static int sack_timer_max = 500; static int addr_scope_max = 3; /* check sctp_scope_policy_t in include/net/sctp/constants.h for max entries */ +static int rwnd_scale_max = 16; extern int sysctl_sctp_mem[3]; extern int sysctl_sctp_rmem[3]; @@ -284,6 +285,18 @@ static ctl_table sctp_table[] = { .extra1 = &zero, .extra2 = &addr_scope_max, }, + { + .ctl_name = CTL_UNNUMBERED, + .procname = "rwnd_update_shift", + .data = &sctp_rwnd_upd_shift, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &one, + .extra2 = &rwnd_scale_max, + }, + { .ctl_name = 0 } }; -- cgit v1.1