Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 17 Sep 2007 01:50:16 -0700
From:      "Kip Macy" <kip.macy@gmail.com>
To:        "Andre Oppermann" <andre@freebsd.org>
Cc:        Perforce Change Reviews <perforce@freebsd.org>, Kip Macy <kmacy@freebsd.org>
Subject:   Re: PERFORCE change 126488 for review
Message-ID:  <b1fa29170709170150y3b391a22x1a52f4858b6882ca@mail.gmail.com>
In-Reply-To: <46EE30A8.7020809@freebsd.org>
References:  <200709162157.l8GLvpx2080125@repoman.freebsd.org> <46EE30A8.7020809@freebsd.org>

next in thread | previous in thread | raw e-mail | index | archive | help
On 9/17/07, Andre Oppermann <andre@freebsd.org> wrote:
> Kip Macy wrote:
> > http://perforce.freebsd.org/chv.cgi?CH=126488
> >
> > Change 126488 by kmacy@kmacy_home:ethng on 2007/09/16 21:57:27
> >
> >       add a route structure to the inpcb
> >       release the reference to the rt_entry if its set when we free the inpcb
>
> We already had this once before and it was nasty as you had to
> do a full inpcb walk to nuke any references if a route changed.

Nope. If you keep a generation counter for the route in the inpcb and
check it each time in udp_output against the rtentry / route table
you'll know that your cached route is no longer valid. I'm not
currently doing that, but it won't be hard to add.

In any event, incurring a 20% slowdown (in the uncontended case, its
basically crippling in the contended case i.e. 1 flow on the same
route) for an event that occurs < .01% of the time on most networks
seems questionable.

 -Kip



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?b1fa29170709170150y3b391a22x1a52f4858b6882ca>