From d7ca3f780d5f30edd5b0cb31bbb311f0b9c866e6 Mon Sep 17 00:00:00 2001 From: Richard Scheffenegger Date: Thu, 16 Apr 2020 15:59:23 +0000 Subject: [PATCH] Reduce default TCP delayed ACK timeout to 40ms. Reviewed by: kbowling, tuexen Approved by: tuexen (mentor) MFC after: 2 weeks Sponsored by: NetApp, Inc. Differential Revision: https://reviews.freebsd.org/D23281 --- share/man/man7/tuning.7 | 4 ++-- sys/netinet/tcp_timer.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/share/man/man7/tuning.7 b/share/man/man7/tuning.7 index 5720f5f5b886..63e09ecce098 100644 --- a/share/man/man7/tuning.7 +++ b/share/man/man7/tuning.7 @@ -24,7 +24,7 @@ .\" .\" $FreeBSD$ .\" -.Dd October 30, 2017 +.Dd April 16, 2020 .Dt TUNING 7 .Os .Sh NAME @@ -435,7 +435,7 @@ number of tiny packets flowing across the network in half. The .Fx delayed ACK implementation also follows the TCP protocol rule that -at least every other packet be acknowledged even if the standard 100ms +at least every other packet be acknowledged even if the standard 40ms timeout has not yet passed. Normally the worst a delayed ACK can do is slightly delay the teardown of a connection, or slightly delay the ramp-up diff --git a/sys/netinet/tcp_timer.h b/sys/netinet/tcp_timer.h index 01880c52b84c..6f0c3a46605a 100644 --- a/sys/netinet/tcp_timer.h +++ b/sys/netinet/tcp_timer.h @@ -119,7 +119,7 @@ #define TCP_MAXRXTSHIFT 12 /* maximum retransmits */ -#define TCPTV_DELACK ( hz/10 ) /* 100ms timeout */ +#define TCPTV_DELACK ( hz/25 ) /* 40ms timeout */ /* * If we exceed this number of retransmits for a single segment, we'll consider