<div dir="auto">Interesting stuff... One thing that occurred to me, that they didnt mention... doing an intermediate step, i.e. make a stripped down FPGA dev board, vs the Xylinx or whoever's standard dev board. Even with a radio chipset and parts also on it, could be done much cheaper, and still be a dev platform.<div dir="auto"><br></div><div dir="auto">I also understand that if you could raise <span style="font-family:sans-serif">the $$$$, and push</span> an ASIC out, theres a much greater chance of large scale acceptance. But, it is a lot of $$$$, and for a single version.</div><div dir="auto"><br></div><div dir="auto">Putting out a dedicated FPGA dev board for $100-200 would let a lot of people play with it, students and SW developers.</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jun 22, 2021, 9:00 AM <<a href="mailto:make-wifi-fast-request@lists.bufferbloat.net">make-wifi-fast-request@lists.bufferbloat.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Send Make-wifi-fast mailing list submissions to<br>
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Today's Topics:<br>
<br>
1. the myth of spectrum scarcity (Dave Taht)<br>
2. openwifi presentation (Dave Taht)<br>
3. Re: [PATCH mac80211-next v8] mac80211: Switch to a virtual<br>
time-based airtime scheduler (Toke Høiland-Jørgensen)<br>
<br><br><br>---------- Forwarded message ----------<br>From: Dave Taht <<a href="mailto:dave.taht@gmail.com" target="_blank" rel="noreferrer">dave.taht@gmail.com</a>><br>To: Make-Wifi-fast <<a href="mailto:make-wifi-fast@lists.bufferbloat.net" target="_blank" rel="noreferrer">make-wifi-fast@lists.bufferbloat.net</a>><br>Cc: <br>Bcc: <br>Date: Mon, 21 Jun 2021 09:55:24 -0700<br>Subject: [Make-wifi-fast] the myth of spectrum scarcity<br>this was really good:<br>
<br>
<a href="https://ecfsapi.fcc.gov/file/7020396128.pdf" rel="noreferrer noreferrer" target="_blank">https://ecfsapi.fcc.gov/file/7020396128.pdf</a><br>
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Dave Täht CTO, TekLibre, LLC<br>
<br>
<br><br><br>---------- Forwarded message ----------<br>From: Dave Taht <<a href="mailto:dave.taht@gmail.com" target="_blank" rel="noreferrer">dave.taht@gmail.com</a>><br>To: Make-Wifi-fast <<a href="mailto:make-wifi-fast@lists.bufferbloat.net" target="_blank" rel="noreferrer">make-wifi-fast@lists.bufferbloat.net</a>><br>Cc: <br>Bcc: <br>Date: Mon, 21 Jun 2021 10:07:23 -0700<br>Subject: [Make-wifi-fast] openwifi presentation<br><a href="https://media.libreplanet.org/u/libreplanet/m/openwifi-project-the-dawn-of-the-free-libre-wifi-chip/" rel="noreferrer noreferrer" target="_blank">https://media.libreplanet.org/u/libreplanet/m/openwifi-project-the-dawn-of-the-free-libre-wifi-chip/</a><br>
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Dave Täht CTO, TekLibre, LLC<br>
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<br><br><br>---------- Forwarded message ----------<br>From: "Toke Høiland-Jørgensen" <<a href="mailto:toke@redhat.com" target="_blank" rel="noreferrer">toke@redhat.com</a>><br>To: Felix Fietkau <<a href="mailto:nbd@nbd.name" target="_blank" rel="noreferrer">nbd@nbd.name</a>><br>Cc: <a href="mailto:make-wifi-fast@lists.bufferbloat.net" target="_blank" rel="noreferrer">make-wifi-fast@lists.bufferbloat.net</a>, Rajkumar Manoharan <<a href="mailto:rmanohar@codeaurora.org" target="_blank" rel="noreferrer">rmanohar@codeaurora.org</a>>, Kan Yan <<a href="mailto:kyan@google.com" target="_blank" rel="noreferrer">kyan@google.com</a>>, Yibo Zhao <<a href="mailto:yiboz@codeaurora.org" target="_blank" rel="noreferrer">yiboz@codeaurora.org</a>>, <a href="mailto:linux-wireless@vger.kernel.org" target="_blank" rel="noreferrer">linux-wireless@vger.kernel.org</a><br>Bcc: <br>Date: Tue, 22 Jun 2021 16:25:03 +0200<br>Subject: Re: [Make-wifi-fast] [PATCH mac80211-next v8] mac80211: Switch to a virtual time-based airtime scheduler<br>Toke Høiland-Jørgensen <<a href="mailto:toke@redhat.com" target="_blank" rel="noreferrer">toke@redhat.com</a>> writes:<br>
<br>
> This switches the airtime scheduler in mac80211 to use a virtual time-based<br>
> scheduler instead of the round-robin scheduler used before. This has a<br>
> couple of advantages:<br>
><br>
> - No need to sync up the round-robin scheduler in firmware/hardware with<br>
> the round-robin airtime scheduler.<br>
><br>
> - If several stations are eligible for transmission we can schedule both of<br>
> them; no need to hard-block the scheduling rotation until the head of the<br>
> queue has used up its quantum.<br>
><br>
> - The check of whether a station is eligible for transmission becomes<br>
> simpler (in ieee80211_txq_may_transmit()).<br>
><br>
> The drawback is that scheduling becomes slightly more expensive, as we need<br>
> to maintain an rbtree of TXQs sorted by virtual time. This means that<br>
> ieee80211_register_airtime() becomes O(logN) in the number of currently<br>
> scheduled TXQs because it can change the order of the scheduled stations.<br>
> We mitigate this overhead by only resorting when a station changes position<br>
> in the tree, and hopefully N rarely grows too big (it's only TXQs currently<br>
> backlogged, not all associated stations), so it shouldn't be too big of an<br>
> issue.<br>
><br>
> To prevent divisions in the fast path, we maintain both station sums and<br>
> pre-computed reciprocals of the sums. This turns the fast-path operation<br>
> into a multiplication, with divisions only happening as the number of<br>
> active stations change (to re-compute the current sum of all active station<br>
> weights). To prevent this re-computation of the reciprocal from happening<br>
> too frequently, we use a time-based notion of station activity, instead of<br>
> updating the weight every time a station gets scheduled or de-scheduled. As<br>
> queues can oscillate between empty and occupied quite frequently, this can<br>
> significantly cut down on the number of re-computations. It also has the<br>
> added benefit of making the station airtime calculation independent on<br>
> whether the queue happened to have drained at the time an airtime value was<br>
> accounted.<br>
><br>
> Co-developed-by: Yibo Zhao <<a href="mailto:yiboz@codeaurora.org" target="_blank" rel="noreferrer">yiboz@codeaurora.org</a>><br>
> Signed-off-by: Yibo Zhao <<a href="mailto:yiboz@codeaurora.org" target="_blank" rel="noreferrer">yiboz@codeaurora.org</a>><br>
> Signed-off-by: Toke Høiland-Jørgensen <<a href="mailto:toke@redhat.com" target="_blank" rel="noreferrer">toke@redhat.com</a>><br>
<br>
Hey Felix<br>
<br>
Had a chance to look at this yet? :)<br>
<br>
-Toke<br>
<br>
<br>
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