From Sebastien.Roy@sun.com Fri Feb 5 07:57:05 2010 Received: from newsunmail1brm.central.sun.com (newsunmail1brm.Central.Sun.COM [129.147.62.245]) by sac.sfbay.sun.com (8.13.8+Sun/8.13.8) with ESMTP id o15Fv5re003323 for ; Fri, 5 Feb 2010 07:57:05 -0800 (PST) Received: from nwk-avmta-1.SFBay.Sun.COM (nwk-avmta-1.SFBay.Sun.COM [129.146.11.74]) by newsunmail1brm.central.sun.com (8.13.7+Sun/8.13.7/ENSMAIL,v2.4) with ESMTP id o15Fv289044880 for <@sunmail2sca.sfbay.sun.com:psarc-ext@sun.com>; Fri, 5 Feb 2010 08:57:05 -0700 (MST) Received: from pmxchannel-daemon.nwk-avmta-1.sfbay.Sun.COM by nwk-avmta-1.sfbay.Sun.COM (Sun Java System Messaging Server 6.2-3.04 (built Jul 15 2005)) id <0KXD0074HLN49H00@nwk-avmta-1.sfbay.Sun.COM> for psarc-ext@sun.com (ORCPT psarc-ext@sun.com); Fri, 05 Feb 2010 07:57:04 -0800 (PST) Received: from brmea-mail-4.sun.com ([192.18.98.36]) by nwk-avmta-1.sfbay.Sun.COM (Sun Java System Messaging Server 6.2-3.04 (built Jul 15 2005)) with ESMTP id <0KXD00L86LLVZOF0@nwk-avmta-1.sfbay.Sun.COM> for psarc-ext@sun.com (ORCPT psarc-ext@sun.com); Fri, 05 Feb 2010 07:56:19 -0800 (PST) Received: from fe-amer-10.sun.com ([192.18.109.80]) by brmea-mail-4.sun.com (8.13.6+Sun/8.12.9) with ESMTP id o15FuJMH020928 for ; Fri, 05 Feb 2010 15:56:19 +0000 (GMT) Received: from conversion-daemon.mail-amer.sun.com by mail-amer.sun.com (Sun Java(tm) System Messaging Server 7u2-7.04 64bit (built Jul 2 2009)) id <0KXD00200LIY5K00@mail-amer.sun.com> for psarc-ext@sun.com (ORCPT psarc-ext@sun.com); Fri, 05 Feb 2010 08:56:19 -0700 (MST) Received: from [192.168.1.2] ([unknown] [173.76.16.34]) by mail-amer.sun.com (Sun Java(tm) System Messaging Server 7u2-7.04 64bit (built Jul 2 2009)) with ESMTPSA id <0KXD002BZLLTFY70@mail-amer.sun.com>; Fri, 05 Feb 2010 08:56:18 -0700 (MST) Date: Fri, 05 Feb 2010 10:56:17 -0500 From: Sebastien Roy Subject: increase max TCP_INIT_CWND [PSARC/2010/042 Self Review] Sender: Sebastien.Roy@sun.com To: psarc-ext@sun.com Cc: Kacheong Poon Message-id: <4B6C3FA1.8080504@sun.com> MIME-version: 1.0 Content-type: text/plain; CHARSET=US-ASCII; format=flowed Content-transfer-encoding: 7BIT X-PMX-Version: 5.4.1.325704 User-Agent: Mozilla/5.0 (X11; U; SunOS i86pc; en-US; rv:1.9.1.5) Gecko/20091207 Lightning/1.0pre Thunderbird/3.0 Status: RO Content-Length: 702 I'm submitting this self-reviewed case on behalf of Kacheong Poon as closed-approved automatic. The release binding is Patch, and the stability level TCP_INIT_CWND is Committed. In 2004/838, the TCP socket option, TCP_INIT_CWND, was introduced. This option controls the initial congestion window (cwnd) used in a TCP connection. The maximum value allowed is 8. This case is to increase this maximum to 16. With today's network technologies, this is a safe value to use in many environments. There is also an on-going effort in IETF to increase the default initial cwnd. This case does not change the default used in Solaris. An app must still use the socket option to change the initial cwnd. From darren.moffat@Sun.COM Fri Feb 5 08:23:04 2010 Received: from sunmail6brm.central.sun.com (sunmail6brm.Central.Sun.COM [129.147.4.169]) by sac.sfbay.sun.com (8.13.8+Sun/8.13.8) with ESMTP id o15GN4AN003962 for ; Fri, 5 Feb 2010 08:23:04 -0800 (PST) Received: from nwk-avmta-2.sfbay.sun.com (nwk-avmta-2.SFBay.Sun.COM [129.145.155.6]) by sunmail6brm.central.sun.com (8.13.8+Sun/8.13.8/ENSMAIL,v2.4) with ESMTP id o15GN1UE014266 for <@sunmail2sca.sfbay.sun.com:psarc-ext@sun.com>; Fri, 5 Feb 2010 10:23:04 -0600 (CST) Received: from pmxchannel-daemon.nwk-avmta-2.sfbay.sun.com by nwk-avmta-2.sfbay.sun.com (Sun Java System Messaging Server 6.2-3.04 (built Jul 15 2005)) id <0KXD00A15MUF0J00@nwk-avmta-2.sfbay.sun.com> for psarc-ext@sun.com (ORCPT psarc-ext@sun.com); Fri, 05 Feb 2010 08:23:03 -0800 (PST) Received: from gmp-eb-inf-1.sun.com ([192.18.6.21]) by nwk-avmta-2.sfbay.sun.com (Sun Java System Messaging Server 6.2-3.04 (built Jul 15 2005)) with ESMTP id <0KXD006KSMUDSW50@nwk-avmta-2.sfbay.sun.com> for psarc-ext@sun.com (ORCPT psarc-ext@sun.com); Fri, 05 Feb 2010 08:23:02 -0800 (PST) Received: from fe-emea-10.sun.com (gmp-eb-lb-1-fe1.eu.sun.com [192.18.6.7] (may be forged)) by gmp-eb-inf-1.sun.com (8.13.7+Sun/8.12.9) with ESMTP id o15GN0ZA029125 for ; Fri, 05 Feb 2010 16:23:01 +0000 (GMT) Received: from conversion-daemon.fe-emea-10.sun.com by fe-emea-10.sun.com (Sun Java(tm) System Messaging Server 7u2-7.04 64bit (built Jul 2 2009)) id <0KXD00H00LNLQA00@fe-emea-10.sun.com> for psarc-ext@sun.com (ORCPT psarc-ext@sun.com); Fri, 05 Feb 2010 16:23:00 +0000 (GMT) Received: from [192.168.1.105] (cpc2-rdng20-2-0-cust917.15-3.cable.virginmedia.com [86.28.167.150]) by fe-emea-10.sun.com (Sun Java(tm) System Messaging Server 7u2-7.04 64bit (built Jul 2 2009)) with ESMTPSA id <0KXD004G9MU48BA0@fe-emea-10.sun.com>; Fri, 05 Feb 2010 16:22:54 +0000 (GMT) Date: Fri, 05 Feb 2010 16:22:51 +0000 From: Darren J Moffat Subject: Re: increase max TCP_INIT_CWND [PSARC/2010/042 Self Review] In-reply-to: <4B6C3FA1.8080504@sun.com> Sender: darren.moffat@Sun.COM To: Sebastien Roy Cc: psarc-ext@Sun.COM, Kacheong Poon Message-id: <4B6C45DB.8000007@Sun.COM> MIME-version: 1.0 Content-type: text/plain; CHARSET=US-ASCII; format=flowed Content-transfer-encoding: 7BIT X-PMX-Version: 5.4.1.325704 References: <4B6C3FA1.8080504@sun.com> User-Agent: Mozilla/5.0 (X11; U; SunOS i86pc; en-US; rv:1.9.1.5) Gecko/20100117 Lightning/1.0b1 Thunderbird/3.0 Status: RO Content-Length: 827 On 05/02/2010 15:56, Sebastien Roy wrote: > I'm submitting this self-reviewed case on behalf of Kacheong Poon as > closed-approved automatic. The release binding is Patch, and the > stability level TCP_INIT_CWND is Committed. > > In 2004/838, the TCP socket option, TCP_INIT_CWND, was introduced. > This option controls the initial congestion window (cwnd) used in > a TCP connection. The maximum value allowed is 8. This case is > to increase this maximum to 16. With today's network technologies, > this is a safe value to use in many environments. There is also > an on-going effort in IETF to increase the default initial cwnd. > This case does not change the default used in Solaris. An app > must still use the socket option to change the initial cwnd. Where does 16 come from ? Why not 32 or 64 ? -- Darren J Moffat From kacheong.poon@sun.com Fri Feb 5 08:38:17 2010 Received: from sunmail3mpk.sfbay.sun.com (sunmail3mpk.SFBay.Sun.COM [129.146.11.52]) by sac.sfbay.sun.com (8.13.8+Sun/8.13.8) with ESMTP id o15GcHkX004327 for ; Fri, 5 Feb 2010 08:38:17 -0800 (PST) Received: from brm-avmta-1.central.sun.com (brm-avmta-1.Central.Sun.COM [129.147.4.11]) by sunmail3mpk.sfbay.sun.com (8.13.8+Sun/8.13.8/ENSMAIL,v2.4) with ESMTP id o15GcELP012172; Fri, 5 Feb 2010 08:38:16 -0800 (PST) Received: from pmxchannel-daemon.brm-avmta-1.central.sun.com by brm-avmta-1.central.sun.com (Sun Java System Messaging Server 6.2-3.04 (built Jul 15 2005)) id <0KXD0011FNJR3Z00@brm-avmta-1.central.sun.com>; Fri, 05 Feb 2010 09:38:15 -0700 (MST) Received: from jurassic-x4600.sfbay.sun.com ([129.146.17.59]) by brm-avmta-1.central.sun.com (Sun Java System Messaging Server 6.2-3.04 (built Jul 15 2005)) with ESMTP id <0KXD00F00NJRMI60@brm-avmta-1.central.sun.com>; Fri, 05 Feb 2010 09:38:15 -0700 (MST) Received: from [10.7.251.223] (punchin-kcpoon.SFBay.Sun.COM [10.7.251.223]) by jurassic-x4600.sfbay.sun.com (8.14.3+Sun/8.14.3) with ESMTP id o15GcCFq603331 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 05 Feb 2010 08:38:14 -0800 (PST) Date: Sat, 06 Feb 2010 00:38:12 +0800 From: Kacheong Poon Subject: Re: increase max TCP_INIT_CWND [PSARC/2010/042 Self Review] In-reply-to: <4B6C45DB.8000007@Sun.COM> To: Darren J Moffat Cc: psarc-ext@sun.com Message-id: <4B6C4974.5020703@sun.com> Organization: Sun Microsystems, Inc. MIME-version: 1.0 Content-type: text/plain; charset=ISO-8859-1; format=flowed Content-transfer-encoding: 7BIT X-PMX-Version: 5.4.1.325704 References: <4B6C3FA1.8080504@sun.com> <4B6C45DB.8000007@Sun.COM> User-Agent: Mozilla/5.0 (X11; U; SunOS i86pc; en-US; rv:1.9.1.7) Gecko/20100115 Thunderbird/3.0.1 Status: RO Content-Length: 1365 On 02/ 6/10 12:22 AM, Darren J Moffat wrote: > On 05/02/2010 15:56, Sebastien Roy wrote: >> I'm submitting this self-reviewed case on behalf of Kacheong Poon as >> closed-approved automatic. The release binding is Patch, and the >> stability level TCP_INIT_CWND is Committed. >> >> In 2004/838, the TCP socket option, TCP_INIT_CWND, was introduced. >> This option controls the initial congestion window (cwnd) used in >> a TCP connection. The maximum value allowed is 8. This case is >> to increase this maximum to 16. With today's network technologies, >> this is a safe value to use in many environments. There is also >> an on-going effort in IETF to increase the default initial cwnd. >> This case does not change the default used in Solaris. An app >> must still use the socket option to change the initial cwnd. > > Where does 16 come from ? Why not 32 or 64 ? It is 2^4 so it must be a good number ;-) A burst of 32 TCP full MSS size segments is probably not OK in most environments today. Is 16 OK? Probably and there are already network equipments using that value as the initial cwnd. And some customers want that. The on-going IETF effort is to increase the default to 10. With a little leeway, 16 seems to be good enough for now. If the need to have a higher value comes, we can increase that. -- K. Poon. kacheong.poon@sun.com From Darren.Moffat@Sun.COM Fri Feb 5 08:45:05 2010 Received: from newsunmail1brm.central.sun.com (newsunmail1brm.Central.Sun.COM [129.147.62.245]) by sac.sfbay.sun.com (8.13.8+Sun/8.13.8) with ESMTP id o15Gj5B8004401 for ; Fri, 5 Feb 2010 08:45:05 -0800 (PST) Received: from nwk-avmta-2.sfbay.sun.com (nwk-avmta-2.SFBay.Sun.COM [129.145.155.6]) by newsunmail1brm.central.sun.com (8.13.7+Sun/8.13.7/ENSMAIL,v2.4) with ESMTP id o15Gj34i018024 for <@sunmail2sca.sfbay.sun.com:psarc-ext@sun.com>; Fri, 5 Feb 2010 09:45:04 -0700 (MST) Received: from pmxchannel-daemon.nwk-avmta-2.sfbay.sun.com by nwk-avmta-2.sfbay.sun.com (Sun Java System Messaging Server 6.2-3.04 (built Jul 15 2005)) id <0KXD00B3TNV46600@nwk-avmta-2.sfbay.sun.com> for psarc-ext@sun.com (ORCPT psarc-ext@sun.com); Fri, 05 Feb 2010 08:45:04 -0800 (PST) Received: from gmp-eb-inf-1.sun.com ([192.18.6.21]) by nwk-avmta-2.sfbay.sun.com (Sun Java System Messaging Server 6.2-3.04 (built Jul 15 2005)) with ESMTP id <0KXD006ESNV1SV80@nwk-avmta-2.sfbay.sun.com> for psarc-ext@sun.com (ORCPT psarc-ext@sun.com); Fri, 05 Feb 2010 08:45:02 -0800 (PST) Received: from fe-emea-09.sun.com (gmp-eb-lb-1-fe1.eu.sun.com [192.18.6.7] (may be forged)) by gmp-eb-inf-1.sun.com (8.13.7+Sun/8.12.9) with ESMTP id o15Gj13k001184 for ; Fri, 05 Feb 2010 16:45:01 +0000 (GMT) Received: from conversion-daemon.fe-emea-09.sun.com by fe-emea-09.sun.com (Sun Java(tm) System Messaging Server 7u2-7.04 64bit (built Jul 2 2009)) id <0KXD00100NO0DU00@fe-emea-09.sun.com> for psarc-ext@sun.com (ORCPT psarc-ext@sun.com); Fri, 05 Feb 2010 16:45:01 +0000 (GMT) Received: from [192.168.1.105] (cpc2-rdng20-2-0-cust917.15-3.cable.virginmedia.com [86.28.167.150]) by fe-emea-09.sun.com (Sun Java(tm) System Messaging Server 7u2-7.04 64bit (built Jul 2 2009)) with ESMTPSA id <0KXD00BN7NUUGJC0@fe-emea-09.sun.com>; Fri, 05 Feb 2010 16:44:55 +0000 (GMT) Date: Fri, 05 Feb 2010 16:44:54 +0000 From: Darren J Moffat Subject: Re: increase max TCP_INIT_CWND [PSARC/2010/042 Self Review] In-reply-to: <4B6C4974.5020703@sun.com> Sender: Darren.Moffat@Sun.COM To: Kacheong Poon Cc: psarc-ext@Sun.COM Message-id: <4B6C4B06.6050903@Sun.COM> MIME-version: 1.0 Content-type: text/plain; CHARSET=US-ASCII; format=flowed Content-transfer-encoding: 7BIT X-PMX-Version: 5.4.1.325704 References: <4B6C3FA1.8080504@sun.com> <4B6C45DB.8000007@Sun.COM> <4B6C4974.5020703@sun.com> User-Agent: Mozilla/5.0 (X11; U; SunOS i86pc; en-US; rv:1.9.1.5) Gecko/20100117 Lightning/1.0b1 Thunderbird/3.0 Status: RO Content-Length: 1432 On 05/02/2010 16:38, Kacheong Poon wrote: > On 02/ 6/10 12:22 AM, Darren J Moffat wrote: >> On 05/02/2010 15:56, Sebastien Roy wrote: >>> I'm submitting this self-reviewed case on behalf of Kacheong Poon as >>> closed-approved automatic. The release binding is Patch, and the >>> stability level TCP_INIT_CWND is Committed. >>> >>> In 2004/838, the TCP socket option, TCP_INIT_CWND, was introduced. >>> This option controls the initial congestion window (cwnd) used in >>> a TCP connection. The maximum value allowed is 8. This case is >>> to increase this maximum to 16. With today's network technologies, >>> this is a safe value to use in many environments. There is also >>> an on-going effort in IETF to increase the default initial cwnd. >>> This case does not change the default used in Solaris. An app >>> must still use the socket option to change the initial cwnd. >> >> Where does 16 come from ? Why not 32 or 64 ? > > > It is 2^4 so it must be a good number ;-) A burst of 32 TCP full > MSS size segments is probably not OK in most environments today. > Is 16 OK? Probably and there are already network equipments > using that value as the initial cwnd. And some customers want that. > The on-going IETF effort is to increase the default to 10. With a > little leeway, 16 seems to be good enough for now. If the need to > have a higher value comes, we can increase that. Okay, thanks for the info. -- Darren J Moffat