Date: Fri, 10 May 2019 10:45:56 -0700 From: Adrian Chadd <adrian.chadd@gmail.com> To: Stephen Patrick <stephen@cablefree.net> Cc: "freebsd-wireless@freebsd.org" <freebsd-wireless@freebsd.org> Subject: Re: TDMA Wireless status? Message-ID: <CAJ-Vmo=KLJ5Xsaoi52EYMpMYNqx7=QDjSOdgfvoZYvvJDHwE-w@mail.gmail.com> In-Reply-To: <CANt51yLuMxWRV_oqYvr3LRVXJAP93fVZVDvk5XbncAW1q6dRXg@mail.gmail.com> References: <CANt51y%2BSgv2O%2B5TV0rsE%2BK_WL%2BuVYGarh54NviY5arVkFsU1Ng@mail.gmail.com> <CAJ-VmokHwKSqtXO6=Yi85xxxJLF9zvDuxzqnzo_BcQTAjJ8v1Q@mail.gmail.com> <CANt51yLhZWi30vGaQGjjJ2fM237huzn-Rmh=9949Lx6d%2Bh9p0Q@mail.gmail.com> <CAJ-Vmon2DJWZjMUHea8O=bYZ1cN1k=MnikCp4UEwaTwJZMziJQ@mail.gmail.com> <CANt51yJQ=iX7afgCQZrd1EqgjmCp8kPnbQ_mmvZL7qV6DvyZmg@mail.gmail.com> <CAJ-VmokOw0Tb18gLb4S8ezy76SEOL1sc1Gpmx%2BGRXYDTuJnvbQ@mail.gmail.com> <CANt51yLuMxWRV_oqYvr3LRVXJAP93fVZVDvk5XbncAW1q6dRXg@mail.gmail.com>
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I'm too busy right now! sorry! -a On Fri, 10 May 2019 at 10:09, Stephen Patrick <stephen@cablefree.net> wrote: > That sounds really interesting! > > Is anyone - your or others - interested in pursuing this work further? > We are very interested - > > Look forward to hearing more, > Best regards > > Stephen > > > On Thu, 9 May 2019 at 19:55, Adrian Chadd <adrian.chadd@gmail.com> wrote: > >> hi! >> >> Ok, so the 30 second version: >> >> * the AR54xx, AR91xx and later 11n chips had some changes to the >> resolution of the timers that Sam used to control transmit timing and >> windows; that should all work fine; >> * there's no rate control right now, it's "stuff as many frames into the >> queue and let the hardware transmit what it can when it can"; that isn't >> optimal but it works fine; >> * Sam didn't publish code to support >1 STA but I don't think it'd be >> hard to add that support. >> >> SO, out of the box the basic TDMA bits work. But! >> >> The important gotcha - on the AR9380 and later chips the DMA engine logic >> changed. The "FIFO" model uses a FIFO of TX descriptor lists. The earlier >> model just had TX descriptor list that you would append to. Unfortunately >> when they added that they changed the ungate to ungate a single FIFO entry, >> rather than run the DMA engine until all the txop timers had completed. >> >> So for example if you pushed in eight individual packets into 8 FIFO >> slots in the voice queue and then you got a voice TxOP, you may notice >> you're only getting a /single/ FIFO slot - ie, one packet - each TxOP. >> >> This shows up when doing TDMA because, unfortunately, the TDMA TX uses >> the TxOP window to control how long each TDMA burst is. So if you only fill >> in a couple of frames per FIFO slot, it will only transmit a couple frames >> per TXOP window. I did some hackery in if_ath_tx_edma.c to try and build up >> larger lists of frames to send to the hardware and it proved that i can hit >> the theoretical max. But it's not optimal, because say you only send 3/4 of >> your frame list in a single FIFO slot. Well, the next TXOP it'll only send >> the last 1/4 and then stop until the next TXOP when it'll grab the next >> FIFO slot. So, the "right" behaviour would be to push roughly a TXOP worth >> of frames into a FIFO slot and hope that you're mostly hitting the >> theoretical maximum. >> >> I never got around to implementing AMPDU on it because, well, I got busy >> with life. AMPDU is a bit of a pain because we'd have to implement delayed >> block-ack in net80211 and .. again, I never got around to it. It's not >> impossible, but someone's gonna have to do it. (ie, you'd send A-MPDU >> bursts during your TxOP and then there would be either a delayed block-ack >> response in the next burst from the receiver, or it would use its beacon >> interval to piggyback the delayed block ack on.) >> >> I hope that helps! >> >> >> >> -adrian >> >> >> On Thu, 25 Apr 2019 at 04:20, Stephen Patrick <stephen@cablefree.net> >> wrote: >> >>> Hello Adrian! >>> >>> Yes, we're certainly very interested. >>> >>> Ideally, looking for a developer who could assist in making this real & >>> working. >>> >>> Look forward to hearing more, >>> Best regards >>> >>> Stephen >>> >>> >>> On Sat, 13 Apr 2019 at 19:46, Adrian Chadd <adrian.chadd@gmail.com> >>> wrote: >>> >>>> Hi, >>>> >>>> There's some work done on the ath(4) hardware for 11a parts done by Sam >>>> Leffler. I fixed it for 11n parts. It's in FreeBSD-HEAD. >>>> >>>> I figured out how to get it mostly working on the AR93xx/AR94xx parts >>>> too but it turns out there are some significant hardware changes in how the >>>> MAC schedules packets that a whole lot of work needs to be done to get >>>> effective TDMA on those parts. >>>> >>>> If you're interested in it I can brain dump where I was at with it! >>>> >>>> >>>> -adrian >>>> >>>> On Fri, 12 Apr 2019 at 01:51, Stephen Patrick <stephen@cablefree.net> >>>> wrote: >>>> >>>>> Thanks Adrian, >>>>> >>>>> We are interested in "long range outdoor" (10-20km) with high gain >>>>> antennas. >>>>> Do you know "Mikrotik Nstreme/NV2" and "Ubiquity Airmax" ? >>>>> Those have framing/polling done in software - wrapped around the >>>>> wireless driver. >>>>> Is there equivalent developed in FreeBSD? >>>>> >>>>> Best regards >>>>> >>>>> Stephen >>>>> >>>>> >>>>> On Thu, 11 Apr 2019 at 20:52, Adrian Chadd <adrian.chadd@gmail.com> >>>>> wrote: >>>>> >>>>>> hi! >>>>>> >>>>>> I know that a lot of the 11ac chips do TDMA but the vendors keep the >>>>>> implementation and knobs close to their chest. We don't have any public >>>>>> APIs for it. Sorry :( >>>>>> >>>>>> >>>>>> -a >>>>>> >>>>>> >>>>>> On Thu, 11 Apr 2019 at 10:23, Stephen Patrick <stephen@cablefree.net> >>>>>> wrote: >>>>>> >>>>>>> Dear sirs, >>>>>>> >>>>>>> Is this feature working for point-to-point, and point-to-multipoint >>>>>>> long >>>>>>> range links? >>>>>>> 802.11ac chipsets/modes supported? >>>>>>> >>>>>>> Best regards >>>>>>> >>>>>>> Stephen >>>>>>> >>>>>>> -- >>>>>>> >>>>>>> *Stephen Patrick* >>>>>>> >>>>>>> *Director* >>>>>>> >>>>>>> Wireless Excellence Limited >>>>>>> The Oxford Science Park >>>>>>> G6, Magdalen Centre, Robert Robinson Avenue >>>>>>> Oxford OX4 4GA - United Kingdom >>>>>>> >>>>>>> CAUTION - This message is confidential and may contain privileged >>>>>>> information intended only for the use of the addressee named above. >>>>>>> If you >>>>>>> are not the intended recipient of this message you are hereby >>>>>>> notified that >>>>>>> any use, dissemination, distribution or reproduction of this message >>>>>>> is >>>>>>> prohibited. If you have received this message in error please notify >>>>>>> Wireless Excellence immediately. Any views expressed in this message >>>>>>> are >>>>>>> those of the individual sender and may not necessarily reflect the >>>>>>> views of >>>>>>> Wireless Excellence Ltd. >>>>>>> _______________________________________________ >>>>>>> freebsd-wireless@freebsd.org mailing list >>>>>>> https://lists.freebsd.org/mailman/listinfo/freebsd-wireless >>>>>>> To unsubscribe, send any mail to " >>>>>>> freebsd-wireless-unsubscribe@freebsd.org" >>>>>>> >>>>>> >>>>> >>>>> -- >>>>> >>>>> *Stephen Patrick* >>>>> >>>>> *Director* >>>>> <http://www.cablefree.net/>; >>>>> >>>>> Wireless Excellence Limited >>>>> The Oxford Science Park >>>>> G6, Magdalen Centre, Robert Robinson Avenue >>>>> Oxford OX4 4GA - United Kingdom >>>>> >>>>> Tel: +44 (0) 870 4959169 Mob: +44 (0)7802 425581 >>>>> Email: stephen@cablefree.net Skype: stephenjpatrick Google: >>>>> cablefree.stephen >>>>> >>>>> [image: Facebook] <https://www.facebook.com/cablefree>; [image: >>>>> Linkedin] <http://www.linkedin.com/company/wireless-excellence>; [image: >>>>> RSS] <http://www.cablefree.co.uk/blog>; [image: Youtube] >>>>> <https://www.youtube.com/user/cablefreenet>; [image: Flickr] >>>>> <http://www.flickr.com/photos/cablefree>; [image: Twitter] >>>>> <http://twitter.com/#!/cablefreeltd>; >>>>> >>>>> CAUTION - This message is confidential and may contain privileged >>>>> information intended only for the use of the addressee named above. If you >>>>> are not the intended recipient of this message you are hereby notified that >>>>> any use, dissemination, distribution or reproduction of this message is >>>>> prohibited. If you have received this message in error please notify >>>>> Wireless Excellence immediately. Any views expressed in this message are >>>>> those of the individual sender and may not necessarily reflect the views of >>>>> Wireless Excellence Ltd. >>>>> >>>> >>> >>> -- >>> >>> *Stephen Patrick* >>> >>> *Director* >>> <http://www.cablefree.net/>; >>> >>> Wireless Excellence Limited >>> The Oxford Science Park >>> G6, Magdalen Centre, Robert Robinson Avenue >>> Oxford OX4 4GA - United Kingdom >>> >>> Tel: +44 (0) 870 4959169 Mob: +44 (0)7802 425581 >>> Email: stephen@cablefree.net Skype: stephenjpatrick Google: >>> cablefree.stephen >>> >>> [image: Facebook] <https://www.facebook.com/cablefree>; [image: >>> Linkedin] <http://www.linkedin.com/company/wireless-excellence>; [image: >>> RSS] <http://www.cablefree.co.uk/blog>; [image: Youtube] >>> <https://www.youtube.com/user/cablefreenet>; [image: Flickr] >>> <http://www.flickr.com/photos/cablefree>; [image: Twitter] >>> <http://twitter.com/#!/cablefreeltd>; >>> >>> CAUTION - This message is confidential and may contain privileged >>> information intended only for the use of the addressee named above. If you >>> are not the intended recipient of this message you are hereby notified that >>> any use, dissemination, distribution or reproduction of this message is >>> prohibited. If you have received this message in error please notify >>> Wireless Excellence immediately. Any views expressed in this message are >>> those of the individual sender and may not necessarily reflect the views of >>> Wireless Excellence Ltd. >>> >> > > -- > > *Stephen Patrick* > > *Director* > <http://www.cablefree.net/>; > > Wireless Excellence Limited > The Oxford Science Park > G6, Magdalen Centre, Robert Robinson Avenue > Oxford OX4 4GA - United Kingdom > > Tel: +44 (0) 870 4959169 Mob: +44 (0)7802 425581 > Email: stephen@cablefree.net Skype: stephenjpatrick Google: > cablefree.stephen > > [image: Facebook] <https://www.facebook.com/cablefree>; [image: Linkedin] > <http://www.linkedin.com/company/wireless-excellence>; [image: RSS] > <http://www.cablefree.co.uk/blog>; [image: Youtube] > <https://www.youtube.com/user/cablefreenet>; [image: Flickr] > <http://www.flickr.com/photos/cablefree>; [image: Twitter] > <http://twitter.com/#!/cablefreeltd>; > > CAUTION - This message is confidential and may contain privileged > information intended only for the use of the addressee named above. If you > are not the intended recipient of this message you are hereby notified that > any use, dissemination, distribution or reproduction of this message is > prohibited. If you have received this message in error please notify > Wireless Excellence immediately. Any views expressed in this message are > those of the individual sender and may not necessarily reflect the views of > Wireless Excellence Ltd. >
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