From owner-freebsd-net@FreeBSD.ORG Sat Jun 28 13:08:33 2014 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 74CADE5A for ; Sat, 28 Jun 2014 13:08:33 +0000 (UTC) Received: from mail-qc0-x22a.google.com (mail-qc0-x22a.google.com [IPv6:2607:f8b0:400d:c01::22a]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 2C4CC25F8 for ; Sat, 28 Jun 2014 13:08:33 +0000 (UTC) Received: by mail-qc0-f170.google.com with SMTP id l6so5613113qcy.1 for ; Sat, 28 Jun 2014 06:08:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=DitvbK3YTvxFzKXyb87IuSSRHlb+e/L70AO97a03qcg=; b=xWD/a1z17LCWVi8niSDlSiH5L/VlNqUGDbfItdHwFPiZn1RwHh0Qd6J2OjMpIrU0WI XnE0ViqPEaXWUWUik109qasuzb+ZS5Q1d28MuX+eXQdVr5rbB9j+sR7Yem+hTwCgl6E9 E1ia5iSgy7YD5VvyMa0NkFhCPGuw1R1CSKqQjSIW4VJR2bRAjEELHGx5WWaspv5YdoAK oroPAUbPoYOPPd/ocRHvOhzGte3x9bT774FXz9tliC9wgnWbUJQs7xf9ENGrkUYr4jSl zT2Y1xsC6uUD3FkmyEJ7sH/oq2dzBPvapTgznsk/w6Tjo+QqhnVdURQ9rrVYYEgDInhP DMAw== X-Received: by 10.229.79.2 with SMTP id n2mr41805968qck.11.1403960912225; Sat, 28 Jun 2014 06:08:32 -0700 (PDT) MIME-Version: 1.0 Received: by 10.96.74.69 with HTTP; Sat, 28 Jun 2014 06:07:52 -0700 (PDT) In-Reply-To: References: <20140614101523.GD22187@onelab2.iet.unipi.it> From: Carlos Ferreira Date: Sat, 28 Jun 2014 14:07:52 +0100 Message-ID: Subject: Re: netmap To: Luigi Rizzo Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.18 Cc: "freebsd-net@freebsd.org" , Prashant Upadhyaya X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 28 Jun 2014 13:08:33 -0000 Hello to all. Unfortunately, I have been unable to do the test that Luigi requested due to the lack of hardware. All the Gateworks Cambria SBC that I have are currently allocated to another project. Only in about one week, will I have the opportunity to test it. As soon as I have news, I will post them. :) On 28 June 2014 09:24, Luigi Rizzo wrote: > > > On Saturday, June 28, 2014, Prashant Upadhyaya > wrote: > >> Hi, >> >> Any further news ? >> >> Professor Luigi, one question regarding the tx with netmap. >> Whenever, I write a packet from user space into netmap rings, and if I >> want netmap to send this out immediately, do I necessarily have to do >> a ioctl(fd, NIOCTXSYNC, NULL) ? >> > > Yes it is up to the application to decide when to push packets out with a > txsync or select() or poll(), and unfortunately there is a tradeoff betwe= en > efficiency and latency > > Cheers > Luigi > > >> >> I have an application which receives packets, does some processing and >> then sends them out. If I keep doing ioctl's on every packet send, then >> there will be too may system calls hitting performance, the application >> can't afford to block it has to return back to polling for the receipt o= f >> next packet. >> >> On the receive side, I see that I don't have a problem because I can pol= l >> the ring without initiating an RXSYNC and whenever in user space I find >> that there is nothing on the ring (probably half way down the ring size)= , I >> do an RXSYNC to get more packets thus saving system calls. >> >> But on tx side, I have noticed that unless I do a TXSYNC, the packet doe= s >> not go out, please let me know if I am missing something. >> >> Regards >> -Prashant >> >> >> >> On Tue, Jun 17, 2014 at 7:33 PM, Carlos Ferreira >> wrote: >> >>> Great! :) >>> I will give you the results as soon as I can get them :) >>> >>> >>> >>> On 17 June 2014 12:55, Luigi Rizzo wrote: >>> >>> > On Mon, Jun 16, 2014 at 5:30 PM, Carlos Ferreira < >>> carlosmf.pt@gmail.com> >>> > wrote: >>> > >>> >> Ok, thanks for the enlightenment regarding the loss of performance. >>> >> >>> >> One question, just to be sure. Does the kernel module contains the >>> VALA >>> >> switch code? Or do I need to compile extra code to have the switch >>> working? >>> >> Also, where can I find the documentation to use the Vala Switch? >>> >> >>> > >>> > =E2=80=8BVALE is part of the netmap kernel module, the only thing you= need >>> > to know to use it is port names: >>> > you can have multiple switch instances with multiple ports each, >>> > >>> > valeX:Y means port Y on switch X, X and Y are arbitrary strings >>> > with the constraint that the whole name must fit 15 characters. >>> > >>> > Details in the netmap manpage >>> > >>> > cheers >>> > luigi >>> > >>> > >>> >>> >>> -- >>> >>> Carlos Miguel Ferreira >>> Researcher at Telecommunications Institute >>> Aveiro - Portugal >>> Work E-mail - cmf@av.it.pt >>> Skype & GTalk -> carlosmf.pt@gmail.com >>> LinkedIn -> http://www.linkedin.com/in/carlosmferreira >>> _______________________________________________ >>> freebsd-net@freebsd.org mailing list >>> http://lists.freebsd.org/mailman/listinfo/freebsd-net >>> To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >>> >> >> > > -- > -----------------------------------------+------------------------------- > Prof. Luigi RIZZO, rizzo@iet.unipi.it . Dip. di Ing. dell'Informazione > http://www.iet.unipi.it/~luigi/ . Universita` di Pisa > TEL +39-050-2211611 . via Diotisalvi 2 > Mobile +39-338-6809875 . 56122 PISA (Italy) > -----------------------------------------+------------------------------- > > --=20 Carlos Miguel Ferreira Researcher at Telecommunications Institute Aveiro - Portugal Work E-mail - cmf@av.it.pt Skype & GTalk -> carlosmf.pt@gmail.com LinkedIn -> http://www.linkedin.com/in/carlosmferreira