From owner-dev-commits-src-all@freebsd.org Mon Feb 15 21:56:56 2021 Return-Path: Delivered-To: dev-commits-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id C23EB53BF3D for ; Mon, 15 Feb 2021 21:56:56 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4DfdHD5BVbz3jDd; Mon, 15 Feb 2021 21:56:56 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id A125E24F7F; Mon, 15 Feb 2021 21:56:56 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 11FLuu1l083274; Mon, 15 Feb 2021 21:56:56 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 11FLuulB083273; Mon, 15 Feb 2021 21:56:56 GMT (envelope-from git) Date: Mon, 15 Feb 2021 21:56:56 GMT Message-Id: <202102152156.11FLuulB083273@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org From: Richard Scheffenegger Subject: git: 1e76911d62ed - releng/13.0 - Adding PRR sysctls to tcp(4) man page MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: rscheff X-Git-Repository: src X-Git-Refname: refs/heads/releng/13.0 X-Git-Reftype: branch X-Git-Commit: 1e76911d62ed4b66bc21cfc22101ef6b20cd6630 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for all branches of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 15 Feb 2021 21:56:56 -0000 The branch releng/13.0 has been updated by rscheff: URL: https://cgit.FreeBSD.org/src/commit/?id=1e76911d62ed4b66bc21cfc22101ef6b20cd6630 commit 1e76911d62ed4b66bc21cfc22101ef6b20cd6630 Author: Richard Scheffenegger AuthorDate: 2021-02-12 11:32:48 +0000 Commit: Richard Scheffenegger CommitDate: 2021-02-15 21:56:39 +0000 Adding PRR sysctls to tcp(4) man page Documenting the newly added, and enabled by default, Proportional Rate Reduction algorithm's governing sysctls. Reviewed by: kbowling, rgrimes Approved by: re(gjb) MFC after: 3 days Sponsored by: NetApp, Inc. Differential Revision: https://reviews.freebsd.org/D28568 (cherry picked from commit a78fee8182614593992e841fbb0d4a958f70da0f) --- share/man/man4/tcp.4 | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/share/man/man4/tcp.4 b/share/man/man4/tcp.4 index dee4040c0a98..431bcd95513b 100644 --- a/share/man/man4/tcp.4 +++ b/share/man/man4/tcp.4 @@ -34,7 +34,7 @@ .\" From: @(#)tcp.4 8.1 (Berkeley) 6/5/93 .\" $FreeBSD$ .\" -.Dd January 14, 2021 +.Dd February 11, 2021 .Dt TCP 4 .Os .Sh NAME @@ -544,9 +544,22 @@ This gently reduces the congestion window during periods, where TCP is application limited and the network bandwidth is not utilized completely. That prevents self-inflicted packet losses once the application starts to transmit data at a higher speed. +.It Va do_prr +Perform SACK loss recovery using the Proportional Rate Reduction (PRR) algorithm +described in RFC6937. +This improves the effectiveness of retransmissions particular in environments +with ACK thinning or burst loss events, as chances to run out of the ACK clock +are reduced, preventing lengthy and performance reducing RTO based loss recovery +(default is true). +.It Va do_prr_conservative +While doing Proportional Rate Reduction, remain strictly in a packet conserving +mode, sending only one new packet for each ACK received. +Helpful when a misconfigured token bucket traffic policer causes persistent +high losses leading to RTO, but reduces PRR effectiveness in more common settings +(default is false). .It Va rfc6675_pipe Calculate the bytes in flight using the algorithm described in RFC 6675, and -is also a prerequisite to enable Proportional Rate Reduction. +is also an improvement when Proportional Rate Reduction is enabled. .It Va rfc3042 Enable the Limited Transmit algorithm as described in RFC 3042. It helps avoid timeouts on lossy links and also when the congestion window