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Date:      Sun, 20 May 2012 11:27:13 -0400
From:      grarpamp <grarpamp@gmail.com>
To:        freebsd-net@freebsd.org
Subject:   Fwd: [Ntop-misc] Announce: libzero (netmap)
Message-ID:  <CAD2Ti288WaE6Rsjf8eDRpK53nv3MsvmPzQNTWerj1VjzSxjyrw@mail.gmail.com>

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fwd, re: developments related to netmap.


---------- Forwarded message ----------
From: Luca Deri <deri@ntop.org>
Date: Mon, May 14, 2012 at 10:13 AM
Subject: [Ntop-misc] Announce: libzero
To: ntop-misc@listgateway.unipi.it, ntop@unipi.it


Hi all,
Last year we have introduced PF_RING DNA for implementing 0% CPU
receive/transmission on commodity 1/10 Gbit network adapters. We
considered DNA as a starting point, as it implemented high-speed RX/TX
that was enough for most, but not all of you. This is because
commodity adapters do not feature advanced packet balancing techniques
as they rely on=C2=A0RSS, that has several limitations such as asymmetric
flow balancing (i.e. the two direction of the same flow are spread
onto two different cores) and inability to provide users a way to use
their balancing function. Another limitation of DNA, again due to its
nature that is close to the hardware, is that packets should be
processed in sequence (i.e. in FIFO) whereas applications sometimes
need to store packets and process them out of sequence (e.g. in case
of fragmented packets, a given packet must be rebuilt with all
fragments prior to process it).

Although zero-copy is often a buzzword as only a subset of packet
management is really performed without copying any packet, at ntop we
decided to see whether it was really possible implement zero-copy for
all operations, including packet dispatching to threads and
applications (including packet fan-out support), packet queuing, and
forwarding across interfaces. This is what=C2=A0libzero=C2=A0is for: as its=
 name
says, we can do all these operations in zero-copy, with no performance
penalty as you will still be able to reach line rate with minimal
packet size (14.88 Mpps with 60+4 bytes packets).

Libzero=C2=A0opens up a new world of opportunities, as it enables
developers to focus on their application leaving to the library the
task of handling packet memory, prefetching memory to let your
applications access packet payload at the same speed as counting
packets. Now you can finally scale up applications, as you can for
instance spawn several snort applications and, without changing a
single line of its code, let each instance handle a coherent (across
directions) set of packets, all at line rate. In a nutshell, the
network is no longer the bottleneck nor the source of complexity.

The ball is on the software side again. You can find all details at
the=C2=A0libzero home page (
http://www.ntop.org/products/pf_ring/libzero-for-dna/).

Enjoy, Luca and Alfredo



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