Date: Thu, 25 Aug 2016 10:55:30 -0700 From: hiren panchasara <hiren@strugglingcoder.info> To: Andrew Gallatin <gallatin@FreeBSD.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r303626 - in head/sys: netinet netinet6 Message-ID: <20160825175530.GE41576@strugglingcoder.info> In-Reply-To: <201608011702.u71H2L1e095815@repo.freebsd.org> References: <201608011702.u71H2L1e095815@repo.freebsd.org>
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--WK3l2KTTmXPVedZ6 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 08/01/16 at 05:02P, Andrew Gallatin wrote: > Author: gallatin > Date: Mon Aug 1 17:02:21 2016 > New Revision: 303626 > URL: https://svnweb.freebsd.org/changeset/base/303626 >=20 > Log: > Rework IPV6 TCP path MTU discovery to match IPv4 > =20 > - Re-write tcp_ctlinput6() to closely mimic the IPv4 tcp_ctlinput() > =20 > - Now that tcp_ctlinput6() updates t_maxseg, we can allow ip6_output() > to send TCP packets without looking at the tcp host cache for every > single transmit. > =20 > - Make the icmp6 code mimic the IPv4 code & avoid returning > PRC_HOSTDEAD because it is so expensive. > =20 > Without these changes in place, every TCP6 pmtu discovery or host > unreachable ICMP resulted in a call to in6_pcbnotify() which walks the > tcbinfo table with the write lock held. Because the tcbinfo table is > shared between IPv4 and IPv6, this causes huge scalabilty issues on > servers with lots of (~100K) TCP connections, to the point where even > a small percent of IPv6 traffic had a disproportionate impact on > overall throughput. > =20 > Reviewed by: bz, rrs, ae (all earlier versions), lstewart (in Netflix's= tree) > Sponsored by: Netflix > Differential Revision: https://reviews.freebsd.org/D7272 Drew, What do you think about getting this into stable/11? Cheers, Hiren --WK3l2KTTmXPVedZ6 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQF8BAABCgBmBQJXvzESXxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXRBNEUyMEZBMUQ4Nzg4RjNGMTdFNjZGMDI4 QjkyNTBFMTU2M0VERkU1AAoJEIuSUOFWPt/lM7QIAIBoJTM2xYZufinQws2kOWMb IuhNv2YX31Savtyh4xz2CReKsA9g3fnXD8Sd/JP19w6LvU7JQtRZGAwczcwumhVM za37Eqei9NYlptGKfmXfBQfNifzIkbiK5GFFOH/itc55tX1kuXQhZHW5lJishoVG 8LcdimI1pljuBIP72XeUjHQ2zB0le4lBJIU0PdfYwqtyPRXyolz8R+sL+tcqGZl/ Jfp7RdSP+gmq4qOr56pISTNseMayIdFMAdAD+iYUu76Sg8tG+JVsdyQOray9MTL1 o5GR4+lvg4snjcKrX7cFLJsxp3V9Zl0Rt6685PLJE4m/jbzUDQSF7lu9//BcESE= =Siao -----END PGP SIGNATURE----- --WK3l2KTTmXPVedZ6--
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