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Date: Wed, 14 Aug 2013 15:47:13 +0400
From: Lev Serebryakov <lev@FreeBSD.org>
Organization: FreeBSD
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Message-ID: <587579055.20130814154713@serebryakov.spb.ru>
To: Luigi Rizzo <rizzo@iet.unipi.it>
Subject: Re: it's the output, not ack coalescing (Re: TSO and FreeBSD vs Linux)
In-Reply-To: <20130814102109.GA63246@onelab2.iet.unipi.it>
References: <520A6D07.5080106@freebsd.org> <520AFBE8.1090109@freebsd.org>
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Cc: Lawrence Stewart <lstewart@freebsd.org>, FreeBSD Net <net@freebsd.org>
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Hello, Luigi.
You wrote 14 =D0=B0=D0=B2=D0=B3=D1=83=D1=81=D1=82=D0=B0 2013 =D0=B3., 14:21=
:09:

LR> Then the problem remains that we should keep a copy of route and
LR> arp information in the socket instead of redoing the lookups on
LR> every single transmission, as they consume some 25% of the time of
LR> a sendto(), and probably even more when it comes to large tcp
LR> segments, sendfile() and the like.
  And we should invalidate this info on ARP/route changes, or connection
 will be lost in such cases, am I right?.. So, on each such event code
 should look into all sockets and check, if routing/ARP information is still
 valid for them. Or we should store lists of sockets in routing and ARP
 tables... I don't know, what is worse.


--=20
// Black Lion AKA Lev Serebryakov <lev@FreeBSD.org>