Date: Mon, 27 Sep 2010 12:12:18 +0400 From: Maxim Dounin <mdounin@mdounin.ru> To: Andre Oppermann <andre@freebsd.org> Cc: freebsd-net@freebsd.org, Igor Sysoev <is@rambler-co.ru>, Lawrence Stewart <lstewart@freebsd.org> Subject: Re: net.inet.tcp.slowstart_flightsize in 8-STABLE Message-ID: <20100927081217.GM44164@mdounin.ru> In-Reply-To: <20100913172453.GG99657@mdounin.ru> References: <20100512124702.GJ2679@rambler-co.ru> <20100713140051.GV99657@mdounin.ru> <4C5BCE48.5070504@freebsd.org> <20100913172453.GG99657@mdounin.ru>
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Hello! On Mon, Sep 13, 2010 at 09:24:53PM +0400, Maxim Dounin wrote: [...] > Andre, could you please take a look at one more patch as well? > > Igor reported that it still sees 100ms delays with rfc3465 turned > on, and it turns out to be similar issue (setting cwnd to 1*MSS) > for hosts found in hostcache. > > The problem with setting cwnd from hostcache was already reported > here: > > http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/92690 > http://lists.freebsd.org/pipermail/freebsd-net/2007-July/014780.html > > As using larger cwnd from hostcache may cause problems on > congested links (see second thread) I changed code to only use > cached cwnd as an upper bound for cwnd (instead of fixing current > code). This is also in-line with what we do on connection > restarts. > > We may later consider re-adding usage of larger cwnd from > hostcache. But I believe it should be done carefully and > probably behind sysctl, off by default. Ping. Maxim Dounin
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