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From:   Dave Taht <dave.taht@gmail.com>
Date:   Mon, 19 Nov 2018 17:04:43 -0800
Message-ID: <CAA93jw60e-oV_axeNg6JoJGXhjUxbr==nnRvoBiJS3eQF_ZO3A@mail.gmail.com>
Subject: Re: [Make-wifi-fast] [PATCH v3 3/6] mac80211: Add airtime accounting
 and scheduling to TXQs
To:     Simon Barber <simon@superduper.net>
Cc:     Ben Greear <greearb@candelatech.com>,
        =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= <toke@toke.dk>,
        Rajkumar Manoharan <rmanohar@codeaurora.org>,
        Make-Wifi-fast <make-wifi-fast@lists.bufferbloat.net>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        ath10k <ath10k@lists.infradead.org>, Felix Fietkau <nbd@nbd.name>
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On Mon, Nov 19, 2018 at 4:52 PM Simon Barber <simon@superduper.net> wrote:
>
> Low-e glass, it=E2=80=99s a thin metallic film used to reflect infra-red =
to keep heat in or out. Totally blocks/reflects RF.

Very cool. I imagine it's hell on cell too?

I can see this stuff becoming very popular in places where keeping the
good wifi in is important. Could cover floors and ceilings with it to.
Cars could be tempest rated...

/me goes looking for stock to buy

> Simon
>
> On Nov 19, 2018, at 4:20 PM, Ben Greear <greearb@candelatech.com> wrote:
>
> On 11/19/2018 04:13 PM, Dave Taht wrote:
>
> On Mon, Nov 19, 2018 at 3:56 PM Ben Greear <greearb@candelatech.com> wrot=
e:
>
>
> On 11/19/2018 03:47 PM, Dave Taht wrote:
>
> On Mon, Nov 19, 2018 at 3:30 PM Simon Barber <simon@superduper.net> wrote=
:
>
>
>
>
> On Nov 19, 2018, at 2:44 PM, Toke H=C3=B8iland-J=C3=B8rgensen <toke@toke.=
dk> wrote:
>
> Dave Taht <dave@taht.net> writes:
>
> Toke H=C3=B8iland-J=C3=B8rgensen <toke@toke.dk> writes:
>
> Felix Fietkau <nbd@nbd.name> writes:
>
> On 2018-11-14 18:40, Toke H=C3=B8iland-J=C3=B8rgensen wrote:
>
> This part doesn't really make much sense to me, but maybe I'm
> misunderstanding how the code works.
> Let's assume we have a driver like ath9k or mt76, which tries to keep a
>
> =E2=80=A6.
>
>
> Well, there's going to be a BQL-like queue limit (but for airtime) on
> top, which drivers can opt-in to if the hardware has too much queueing.
>
>
> Very happy to read this - I first talked to Dave Taht about the need for =
Time Queue Limits more than 5 years ago!
>
>
> Michal faked up a dql estimator 3 (?) years ago. it worked.
>
> http://blog.cerowrt.org/post/dql_on_wifi_2/
>
> As a side note, in *any* real world working mu-mimo situation at any
> scale, on any equipment, does anyone have any stats on how often the
> feature is actually used and useful?
>
> My personal guess, from looking at the standard, was in home
> scenarios, usage would be about... 0, and in a controlled environment
> in a football stadium, quite a lot.
>
> In a office or apartment complex, I figured interference and so forth
> would make it a negative benefit due to retransmits.
>
> I felt when that part of the standard rolled around... that mu-mimo
> was an idea that should never have escaped the lab. I can be convinced
> by data, that we can aim for a higher goal here. But it would be
> comforting to have a measured non-lab, real-world, at real world
> rates, result for it, on some platform, of it actually being useful.
>
>
> We're working on building a lab with 20 or 30 mixed 'real' devices
> using various different /AC NICs (QCA wave2 on OpenWRT, Fedora, realtek U=
SB 8812au on OpenWRT, Fedora,
> and some Intel NICs in NUCs on Windows, and maybe more).  I'm not actuall=
y sure if that realtek
>  or the NUCs can do MU-MIMO or not, but the QCA NICs will be able to.  It=
 should be at least somewhat similar
> to a classroom environment or coffee shop.
>
>
> In the last 3 coffee shops I went to, I could hear over 30 APs on
> competing SSIDs, running G, N, and AC,
> occupying every available channel.
>
>
> I especially like when someone uses channel 3 because, I guess, they
> think it is un-used :)
>
> I'm not sure if this was a fluke or not, but at Starbucks recently I sat =
outside,
> right next to their window, and could not scan their AP at all.  Previous=
ly, I sat
> inside, 3 feet away through the glass, and got great signal.  I wonder wh=
at that was
> all about!  Maybe special tinting that blocks RF?  Or just dumb luck of s=
ome sort.
>
> Thanks,
> Ben
>
>
> --
> Ben Greear <greearb@candelatech.com>
> Candela Technologies Inc  http://www.candelatech.com
>
>


--=20

Dave T=C3=A4ht
CTO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-831-205-9740