From 2a9aae9e5f7a1a218b2c05ed28d811e533912118 Mon Sep 17 00:00:00 2001 From: Richard Scheffenegger Date: Wed, 8 May 2024 14:36:53 +0200 Subject: [PATCH] tcp: add counter to track when SACK loss recovery uses TSO Add a counter to track how frequently SACK has transmitted more than one MSS using TSO. Instances when this will be beneficial is the use of PRR, or when ACK thinning due to GRO/LRO or ACK discards by the network are present. Reviewed By: tuexen, #transport Sponsored by: NetApp, Inc. Differential Revision: https://reviews.freebsd.org/D45070 --- sys/netinet/in_kdtrace.c | 1 + sys/netinet/in_kdtrace.h | 1 + sys/netinet/tcp_output.c | 3 +++ sys/netinet/tcp_var.h | 3 ++- usr.bin/netstat/inet.c | 8 +++++--- 5 files changed, 12 insertions(+), 4 deletions(-) diff --git a/sys/netinet/in_kdtrace.c b/sys/netinet/in_kdtrace.c index 2a53b11c3be..8491a4d49d9 100644 --- a/sys/netinet/in_kdtrace.c +++ b/sys/netinet/in_kdtrace.c @@ -294,6 +294,7 @@ MIB_PROBE_TCP(tcps_finwait2_drops); MIB_PROBE_TCP(tcps_sack_recovery_episode); MIB_PROBE_TCP(tcps_sack_rexmits); +MIB_PROBE_TCP(tcps_sack_rexmits_tso); MIB_PROBE_TCP(tcps_sack_rexmit_bytes); MIB_PROBE_TCP(tcps_sack_rcv_blocks); MIB_PROBE_TCP(tcps_sack_send_blocks); diff --git a/sys/netinet/in_kdtrace.h b/sys/netinet/in_kdtrace.h index 78083929999..9896af96eb8 100644 --- a/sys/netinet/in_kdtrace.h +++ b/sys/netinet/in_kdtrace.h @@ -286,6 +286,7 @@ SDT_PROBE_DECLARE(mib, tcp, count, tcps_finwait2_drops); SDT_PROBE_DECLARE(mib, tcp, count, tcps_sack_recovery_episode); SDT_PROBE_DECLARE(mib, tcp, count, tcps_sack_rexmits); +SDT_PROBE_DECLARE(mib, tcp, count, tcps_sack_rexmits_tso); SDT_PROBE_DECLARE(mib, tcp, count, tcps_sack_rexmit_bytes); SDT_PROBE_DECLARE(mib, tcp, count, tcps_sack_rcv_blocks); SDT_PROBE_DECLARE(mib, tcp, count, tcps_sack_send_blocks); diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c index e64b7701c45..c318e8517c2 100644 --- a/sys/netinet/tcp_output.c +++ b/sys/netinet/tcp_output.c @@ -1037,6 +1037,9 @@ send: TCPSTAT_ADD(tcps_sndrexmitbyte, len); if (sack_rxmit) { TCPSTAT_INC(tcps_sack_rexmits); + if (tso) { + TCPSTAT_INC(tcps_sack_rexmits_tso); + } TCPSTAT_ADD(tcps_sack_rexmit_bytes, len); } #ifdef STATS diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h index 6d60c21e64e..01dd7198511 100644 --- a/sys/netinet/tcp_var.h +++ b/sys/netinet/tcp_var.h @@ -1030,6 +1030,7 @@ struct tcpstat { /* SACK related stats */ uint64_t tcps_sack_recovery_episode; /* SACK recovery episodes */ uint64_t tcps_sack_rexmits; /* SACK rexmit segments */ + uint64_t tcps_sack_rexmits_tso; /* SACK rexmit TSO chunks */ uint64_t tcps_sack_rexmit_bytes; /* SACK rexmit bytes */ uint64_t tcps_sack_rcv_blocks; /* SACK blocks (options) received */ uint64_t tcps_sack_send_blocks; /* SACK blocks (options) sent */ @@ -1088,7 +1089,7 @@ struct tcpstat { uint64_t tcps_tlpresend_bytes; /* number of bytes resent by tlp */ - uint64_t _pad[4]; /* 4 TBD placeholder for STABLE */ + uint64_t _pad[3]; /* 3 TBD placeholder for STABLE */ }; #define tcps_rcvmemdrop tcps_rcvreassfull /* compat */ diff --git a/usr.bin/netstat/inet.c b/usr.bin/netstat/inet.c index 0657926eab8..5d7fd0e46cf 100644 --- a/usr.bin/netstat/inet.c +++ b/usr.bin/netstat/inet.c @@ -783,11 +783,13 @@ tcp_stats(u_long off, const char *name, int af1 __unused, int proto __unused) p(tcps_sack_recovery_episode, "\t{:recovery-episodes/%ju} " "{N:/SACK recovery episode%s}\n"); - p(tcps_sack_rexmits, "\t{:segment-retransmits/%ju} " + p(tcps_sack_rexmits, "\t{:segment-retransmits/%ju} " "{N:/segment rexmit%s in SACK recovery episodes}\n"); - p(tcps_sack_rexmit_bytes, "\t{:byte-retransmits/%ju} " + p(tcps_sack_rexmits_tso, "\t{:tso-chunk-retransmits/%ju} " + "{N:/tso chunk rexmit%s in SACK recovery episodes}\n"); + p(tcps_sack_rexmit_bytes, "\t{:byte-retransmits/%ju} " "{N:/byte rexmit%s in SACK recovery episodes}\n"); - p(tcps_sack_rcv_blocks, "\t{:received-blocks/%ju} " + p(tcps_sack_rcv_blocks, "\t{:received-blocks/%ju} " "{N:/SACK option%s (SACK blocks) received}\n"); p(tcps_sack_send_blocks, "\t{:sent-option-blocks/%ju} " "{N:/SACK option%s (SACK blocks) sent}\n");