Date: Sat, 28 Jun 2014 14:07:52 +0100 From: Carlos Ferreira <carlosmf.pt@gmail.com> To: Luigi Rizzo <rizzo@iet.unipi.it> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, Prashant Upadhyaya <praupadhyaya@gmail.com> Subject: Re: netmap Message-ID: <CAJpYY6VBtynBeSQkVprz%2B6BY=TF9RcGEV9hWWKnVQzUvfpKh%2BQ@mail.gmail.com> In-Reply-To: <CA%2BhQ2%2Bgi9SiZuM4Nvw4CjJG9sX3cNZ4KNfXSkDcFfcPvW4A22Q@mail.gmail.com> References: <CAJpYY6Wj6NkYVdPzitswLQ2oVoX9JAv5tCnzbP6icsgJTdfm8Q@mail.gmail.com> <CA%2BhQ2%2BhHz2FKUkCRnHiGAVxZqxY5WHPPo87mVgSnSmPzovNLWw@mail.gmail.com> <CAJpYY6V6Ewc%2BXQYBi3BQbFtWgLiFKN_qmBLjAx1HyWhB9Q0vcg@mail.gmail.com> <CAJpYY6VJ9ih1ON1s1mnzrc-P7Xa_vsVS3UC49gnii0cLX%2B=TNA@mail.gmail.com> <20140614101523.GD22187@onelab2.iet.unipi.it> <CAJpYY6Usfv98OEsgXedP5MCqdJsd_rz7N4EhgRmP2NcxZ9eQ9g@mail.gmail.com> <CA%2BhQ2%2Bj4RrCxjSu79Zt9BVnKUTcRxO615msGH5_uoLrEinbcPQ@mail.gmail.com> <CAJpYY6XBg8=g7sjVbu%2B6%2BEG1-vW1dymsvD8pL-EB08B=_z=usA@mail.gmail.com> <CAPBAu3U9_VTUCPk_61maSAyxM_VHgSui8kbT65=b-jsXNzqJcA@mail.gmail.com> <CA%2BhQ2%2Bgi9SiZuM4Nvw4CjJG9sX3cNZ4KNfXSkDcFfcPvW4A22Q@mail.gmail.com>
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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 <rizzo@iet.unipi.it> wrote: > > > On Saturday, June 28, 2014, Prashant Upadhyaya <praupadhyaya@gmail.com> > 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 <carlosmf.pt@gmail.com> >> wrote: >> >>> Great! :) >>> I will give you the results as soon as I can get them :) >>> >>> >>> >>> On 17 June 2014 12:55, Luigi Rizzo <rizzo@iet.unipi.it> 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
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