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Commit 9c21d2fc authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: add tcp_comp_sack_nr sysctl 



This per netns sysctl allows for TCP SACK compression fine-tuning.

This limits number of SACK that can be compressed.
Using 0 disables SACK compression.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6d82aa24

Documentation/networking/ip-sysctl.txt

+6 −0
Original line number Original line Diff line number Diff line
@@ -532,6 +532,12 @@ tcp_comp_sack_delay_ns - LONG INTEGER 




	Default : 1,000,000 ns (1 ms)

	Default : 1,000,000 ns (1 ms)





tcp_comp_sack_nr - INTEGER

	Max numer of SACK that can be compressed.

	Using 0 disables SACK compression.



	Detault : 44



tcp_slow_start_after_idle - BOOLEAN

tcp_slow_start_after_idle - BOOLEAN

	If set, provide RFC2861 behavior and time out the congestion

	If set, provide RFC2861 behavior and time out the congestion

	window after an idle period.  An idle period is defined at

	window after an idle period.  An idle period is defined at

include/net/netns/ipv4.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -160,6 +160,7 @@ struct netns_ipv4 { 
	int sysctl_tcp_pacing_ca_ratio;

	int sysctl_tcp_pacing_ca_ratio;

	int sysctl_tcp_wmem[3];

	int sysctl_tcp_wmem[3];

	int sysctl_tcp_rmem[3];

	int sysctl_tcp_rmem[3];

	int sysctl_tcp_comp_sack_nr;

	unsigned long sysctl_tcp_comp_sack_delay_ns;

	unsigned long sysctl_tcp_comp_sack_delay_ns;

	struct inet_timewait_death_row tcp_death_row;

	struct inet_timewait_death_row tcp_death_row;

	int sysctl_max_syn_backlog;

	int sysctl_max_syn_backlog;

net/ipv4/sysctl_net_ipv4.c

+10 −0
Original line number Original line Diff line number Diff line
@@ -46,6 +46,7 @@ static int tcp_syn_retries_min = 1; 
static int tcp_syn_retries_max = MAX_TCP_SYNCNT;

static int tcp_syn_retries_max = MAX_TCP_SYNCNT;

static int ip_ping_group_range_min[] = { 0, 0 };

static int ip_ping_group_range_min[] = { 0, 0 };

static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX };

static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX };

static int comp_sack_nr_max = 255;





/* obsolete */

/* obsolete */

static int sysctl_tcp_low_latency __read_mostly;

static int sysctl_tcp_low_latency __read_mostly;
@@ -1158,6 +1159,15 @@ static struct ctl_table ipv4_net_table[] = { 
		.mode		= 0644,

		.mode		= 0644,

		.proc_handler	= proc_doulongvec_minmax,

		.proc_handler	= proc_doulongvec_minmax,

	},

	},

	{

		.procname	= "tcp_comp_sack_nr",

		.data		= &init_net.ipv4.sysctl_tcp_comp_sack_nr,

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.proc_handler	= proc_dointvec_minmax,

		.extra1		= &zero,

		.extra2		= &comp_sack_nr_max,

	},

	{

	{

		.procname	= "udp_rmem_min",

		.procname	= "udp_rmem_min",

		.data		= &init_net.ipv4.sysctl_udp_rmem_min,

		.data		= &init_net.ipv4.sysctl_udp_rmem_min,

net/ipv4/tcp_input.c

+2 −1
Original line number Original line Diff line number Diff line
@@ -5106,7 +5106,8 @@ static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible) 
		return;

		return;

	}

	}





	if (!tcp_is_sack(tp) || tp->compressed_ack >= 44)

	if (!tcp_is_sack(tp) ||

	    tp->compressed_ack >= sock_net(sk)->ipv4.sysctl_tcp_comp_sack_nr)

		goto send_now;

		goto send_now;

	tp->compressed_ack++;

	tp->compressed_ack++;

net/ipv4/tcp_ipv4.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -2573,6 +2573,7 @@ static int __net_init tcp_sk_init(struct net *net) 
		       sizeof(init_net.ipv4.sysctl_tcp_wmem));

		       sizeof(init_net.ipv4.sysctl_tcp_wmem));

	}

	}

	net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;

	net->ipv4.sysctl_tcp_comp_sack_delay_ns = NSEC_PER_MSEC;

	net->ipv4.sysctl_tcp_comp_sack_nr = 44;

	net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;

	net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;

	spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);

	spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);

	net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;

	net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;