Commit 7ec65372 authored by Wei Wang's avatar Wei Wang Committed by David S. Miller
Browse files

tcp: add stat of data packet reordering events 



Introduce a new TCP stats to record the number of reordering events seen
and expose it in both tcp_info (TCP_INFO) and opt_stats
(SOF_TIMESTAMPING_OPT_STATS).
Application can use this stats to track the frequency of the reordering
events in addition to the existing reordering stats which tracks the
magnitude of the latest reordering event.

Note: this new stats tracks reordering events triggered by ACKs, which
could often be fewer than the actual number of packets being delivered
out-of-order.

Signed-off-by: default avatarWei Wang <weiwan@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7e10b655

include/linux/tcp.h

+2 −2
Original line number Diff line number Diff line
@@ -220,8 +220,7 @@ struct tcp_sock { 
#define TCP_RACK_RECOVERY_THRESH 16

		u8 reo_wnd_persist:5, /* No. of recovery since last adj */

		   dsack_seen:1, /* Whether DSACK seen after last adj */

		   advanced:1,	 /* mstamp advanced since last lost marking */

		   reord:1;	 /* reordering detected */

		   advanced:1;	 /* mstamp advanced since last lost marking */

	} rack;

	u16	advmss;		/* Advertised MSS			*/

	u8	compressed_ack;
@@ -267,6 +266,7 @@ struct tcp_sock { 
	u8	ecn_flags;	/* ECN status bits.			*/

	u8	keepalive_probes; /* num of allowed keep alive probes	*/

	u32	reordering;	/* Packet reordering metric.		*/

	u32	reord_seen;	/* number of data packet reordering events */

	u32	snd_up;		/* Urgent pointer		*/



/*

include/uapi/linux/tcp.h

+2 −0
Original line number Diff line number Diff line
@@ -239,6 +239,7 @@ struct tcp_info { 
	__u64	tcpi_bytes_sent;     /* RFC4898 tcpEStatsPerfHCDataOctetsOut */

	__u64	tcpi_bytes_retrans;  /* RFC4898 tcpEStatsPerfOctetsRetrans */

	__u32	tcpi_dsack_dups;     /* RFC4898 tcpEStatsStackDSACKDups */

	__u32	tcpi_reord_seen;     /* reordering events seen */

};



/* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
@@ -264,6 +265,7 @@ enum { 
	TCP_NLA_BYTES_SENT,	/* Data bytes sent including retransmission */

	TCP_NLA_BYTES_RETRANS,	/* Data bytes retransmitted */

	TCP_NLA_DSACK_DUPS,	/* DSACK blocks received */

	TCP_NLA_REORD_SEEN,	/* reordering events seen */

};



/* for TCP_MD5SIG socket option */

net/ipv4/tcp.c

+4 −0
Original line number Diff line number Diff line
@@ -2597,6 +2597,7 @@ int tcp_disconnect(struct sock *sk, int flags) 
	tp->bytes_sent = 0;

	tp->bytes_retrans = 0;

	tp->dsack_dups = 0;

	tp->reord_seen = 0;



	/* Clean up fastopen related fields */

	tcp_free_fastopen_req(tp);
@@ -3207,6 +3208,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info) 
	info->tcpi_bytes_sent = tp->bytes_sent;

	info->tcpi_bytes_retrans = tp->bytes_retrans;

	info->tcpi_dsack_dups = tp->dsack_dups;

	info->tcpi_reord_seen = tp->reord_seen;

	unlock_sock_fast(sk, slow);

}

EXPORT_SYMBOL_GPL(tcp_get_info);
@@ -3234,6 +3236,7 @@ static size_t tcp_opt_stats_get_size(void) 
		nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_SENT */

		nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_RETRANS */

		nla_total_size(sizeof(u32)) + /* TCP_NLA_DSACK_DUPS */

		nla_total_size(sizeof(u32)) + /* TCP_NLA_REORD_SEEN */

		0;

}
@@ -3286,6 +3289,7 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk) 
	nla_put_u64_64bit(stats, TCP_NLA_BYTES_RETRANS, tp->bytes_retrans,

			  TCP_NLA_PAD);

	nla_put_u32(stats, TCP_NLA_DSACK_DUPS, tp->dsack_dups);

	nla_put_u32(stats, TCP_NLA_REORD_SEEN, tp->reord_seen);



	return stats;

}

net/ipv4/tcp_input.c

+2 −1
Original line number Diff line number Diff line
@@ -906,8 +906,8 @@ static void tcp_check_sack_reordering(struct sock *sk, const u32 low_seq, 
				       sock_net(sk)->ipv4.sysctl_tcp_max_reordering);

	}



	tp->rack.reord = 1;

	/* This exciting event is worth to be remembered. 8) */

	tp->reord_seen++;

	NET_INC_STATS(sock_net(sk),

		      ts ? LINUX_MIB_TCPTSREORDER : LINUX_MIB_TCPSACKREORDER);

}
@@ -1871,6 +1871,7 @@ static void tcp_check_reno_reordering(struct sock *sk, const int addend) 


	tp->reordering = min_t(u32, tp->packets_out + addend,

			       sock_net(sk)->ipv4.sysctl_tcp_max_reordering);

	tp->reord_seen++;

	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRENOREORDER);

}

net/ipv4/tcp_recovery.c

+1 −1
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ static u32 tcp_rack_reo_wnd(const struct sock *sk) 
{

	struct tcp_sock *tp = tcp_sk(sk);



	if (!tp->rack.reord) {

	if (!tp->reord_seen) {

		/* If reordering has not been observed, be aggressive during

		 * the recovery or starting the recovery by DUPACK threshold.

		 */

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