From owner-cvs-all  Thu Jul 18 12: 6:19 2002
Delivered-To: cvs-all@freebsd.org
Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id 1B4CD37B400; Thu, 18 Jul 2002 12:06:13 -0700 (PDT)
Received: from freefall.freebsd.org (freefall.FreeBSD.org [216.136.204.21])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id D5B3443E3B; Thu, 18 Jul 2002 12:06:12 -0700 (PDT)
	(envelope-from dillon@FreeBSD.org)
Received: from freefall.freebsd.org (dillon@localhost [127.0.0.1])
	by freefall.freebsd.org (8.12.4/8.12.4) with ESMTP id g6IJ6CJU048668;
	Thu, 18 Jul 2002 12:06:12 -0700 (PDT)
	(envelope-from dillon@freefall.freebsd.org)
Received: (from dillon@localhost)
	by freefall.freebsd.org (8.12.4/8.12.4/Submit) id g6IJ6CJI048667;
	Thu, 18 Jul 2002 12:06:12 -0700 (PDT)
Message-Id: <200207181906.g6IJ6CJI048667@freefall.freebsd.org>
From: Matt Dillon <dillon@FreeBSD.org>
Date: Thu, 18 Jul 2002 12:06:12 -0700 (PDT)
To: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org
Subject: cvs commit: src/sys/netinet tcp_subr.c tcp_timer.c tcp_timer.h
X-FreeBSD-CVS-Branch: HEAD
Sender: owner-cvs-all@FreeBSD.ORG
Precedence: bulk
List-ID: <cvs-all.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20cvs-all>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20cvs-all>
X-Loop: FreeBSD.ORG

dillon      2002/07/18 12:06:12 PDT

  Modified files:
    sys/netinet          tcp_subr.c tcp_timer.c tcp_timer.h 
  Log:
  Introduce two new sysctl's:
  
  net.inet.tcp.rexmit_min (default 3 ticks equiv)
  
      This sysctl is the retransmit timer RTO minimum,
      specified in milliseconds.  This value is
      designed for algorithmic stability only.
  
  net.inet.tcp.rexmit_slop (default 200ms)
  
      This sysctl is the retransmit timer RTO slop
      which is added to every retransmit timeout and
      is designed to handle protocol stack overheads
      and delayed ack issues.
  
  Note that the *original* code applied a 1-second
  RTO minimum but never applied real slop to the RTO
  calculation, so any RTO calculation over one second
  would have no slop and thus not account for
  protocol stack overheads (TCP timestamps are not
  a measure of protocol turnaround!).  Essentially,
  the original code made the RTO calculation almost
  completely irrelevant.
  
  Please note that the 200ms slop is debateable.
  This commit is not meant to be a line in the sand,
  and if the community winds up deciding that increasing
  it is the correct solution then it's easy to do.
  Note that larger values will destroy performance
  on lossy networks while smaller values may result in
  a greater number of unnecessary retransmits.
  
  Revision  Changes    Path
  1.137     +3 -1      src/sys/netinet/tcp_subr.c
  1.52      +8 -0      src/sys/netinet/tcp_timer.c
  1.21      +21 -4     src/sys/netinet/tcp_timer.h

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe cvs-all" in the body of the message