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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Alexei Starovoitov <ast@plumgrid.com>
Cc: Chema Gonzalez <chema@google.com>,
	David Miller <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Daniel Borkmann <dborkman@redhat.com>,
	Network Development <netdev@vger.kernel.org>
Subject: Re: [PATCH] filter: added BPF random opcode
Date: Wed, 16 Apr 2014 18:38:16 -0700	[thread overview]
Message-ID: <1397698696.4222.138.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <CAMEtUuw3-LEuwJ2cAQ+F-tu_-wzy4HK4ZteAuJpYfY9hW66+FA@mail.gmail.com>

On Tue, 2014-04-15 at 23:24 -0700, Alexei Starovoitov wrote:

> In particular I don't find the reason of moving random
> packet sampling into kernel to be that great.
> pcap cannot receive them quickly enough anyway,
> so there are drops already.
> Just randomly pick packets that reached the user space.
> Why add this to the kernel? I don't see how it can improve accuracy.

It has nothing to do with speed or accuracy.

Being able to intercept 0.001 % of the packets (and not 0.001 % of the
flows...) can be useful to network operators.

_Then_ if its super super super fast, thats better, of course.

Suggesting to intercept all packets, then filtering 99.999 % of them in
user space is not going to work. Its going to be super super super slow.

  parent reply	other threads:[~2014-04-17  1:38 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-15 18:16 [PATCH] filter: added BPF random opcode Chema Gonzalez
2014-04-16  6:24 ` Alexei Starovoitov
2014-04-16  8:32   ` Daniel Borkmann
2014-04-17  0:19   ` Chema Gonzalez
2014-04-17  1:38   ` Eric Dumazet [this message]
2014-04-18 20:21     ` Alexei Starovoitov
2014-04-21 16:21 ` [PATCH v2] " Chema Gonzalez
2014-04-21 21:46   ` Alexei Starovoitov
2014-04-21 21:54     ` Chema Gonzalez
2014-04-21 22:20       ` Alexei Starovoitov
2014-04-21 23:19         ` Chema Gonzalez
2014-04-22  2:42           ` Alexei Starovoitov
2014-04-22 21:10   ` Daniel Borkmann
2014-04-23  1:29   ` David Miller
  -- strict thread matches above, loose matches on Subject: below --
2014-04-14 23:02 [PATCH] " Chema Gonzalez
2014-04-15  7:24 ` Daniel Borkmann
2014-04-15 14:41   ` Eric Dumazet
2014-04-15 15:04     ` Daniel Borkmann
2014-04-15 16:22       ` Chema Gonzalez
2014-04-15 16:30   ` Chema Gonzalez
2014-04-15 16:44     ` Daniel Borkmann
2014-04-15 18:19       ` Chema Gonzalez

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