Date: Tue, 27 Jan 2015 21:28:19 +0100 From: =?ISO-8859-1?Q?Olivier_Cochard=2DLabb=E9?= <olivier@cochard.me> To: Michael Sierchio <kudzu@tenebras.com> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, Jim Thompson <jim@netgate.com>, =?ISO-8859-1?Q?Antoine_Beaupr=E9?= <anarcat@koumbit.org> Subject: Re: is polling still a thing? Message-ID: <CA%2Bq%2BTcoanjpNX91vi5EX4-oprm0PiVUYi-EOPRfi6zzXXmwsow@mail.gmail.com> In-Reply-To: <CAHu1Y71XDO1fuCJM_Cw1wm4jt%2BigKisaTWRb4gBX3nsaepwMsQ@mail.gmail.com> References: <871tmgceup.fsf@marcos.anarc.at> <A32D80F3-9D34-4136-A870-B28582F6EAA0@netgate.com> <87vbjsaxxy.fsf@marcos.anarc.at> <CA%2Bq%2BTcrkp3U%2Bb5816es3jsvhNfxpW_v%2BRQOa8a9BbLwNTm3RuQ@mail.gmail.com> <CAHu1Y71XDO1fuCJM_Cw1wm4jt%2BigKisaTWRb4gBX3nsaepwMsQ@mail.gmail.com>
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On Tue, Jan 27, 2015 at 9:15 PM, Michael Sierchio <kudzu@tenebras.com> wrote: > > > On small, embedded computers running ipfw w/kernel nat and device polling > enabled (on em ether adapters), I observed the *reported* system load grow > very high. When disabling polling on the interfaces, it went back to > something normal. > > My impression is that the consensus among the core developers concerned > with networking is that device polling is an ancient hack and is > deprecated. In the case of a DDoS attack, there may be many other things to > try - at the infrastructure level - traffic diversion techniques like BGP > flowspec, use anycast, etc. On the individual server level, use stateful > rules with GRED enabled, dropping most new tcp or udp traffic based on load. > > > If I remember well, Luigi had a surprise regarding the advantage of using polling inside a VM: https://lists.freebsd.org/pipermail/freebsd-net/2013-May/035626.html But on real hardware, since the introduction of interrupt moderation on NIC, polling is not more useful.
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