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From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
To:     Johannes Berg <johannes@sipsolutions.net>,
        Kan Yan <kyan@google.com>
Cc:     linux-wireless@vger.kernel.org,
        make-wifi-fast@lists.bufferbloat.net, ath10k@lists.infradead.org,
        John Crispin <john@phrozen.org>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Felix Fietkau <nbd@nbd.name>,
        Rajkumar Manoharan <rmanohar@codeaurora.org>,
        Kevin Hayes <kevinhayes@google.com>
Subject: Re: [PATCH v2 1/4] mac80211: Rearrange ieee80211_tx_info to make room for tx_time_est
In-Reply-To: <78035e38264feac9d15a761b009c89b9738b4de1.camel@sipsolutions.net>
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Date:   Fri, 18 Oct 2019 16:30:38 +0200
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Johannes Berg <johannes@sipsolutions.net> writes:

> On Fri, 2019-10-18 at 16:01 +0200, Toke H=C3=B8iland-J=C3=B8rgensen wrote=
:
>>=20
>> > We can also play with the units of the airtime, e.g. making that a
>> > multiple of 2 or 4 us? Seems unlikely to matter much?
>>=20
>> Sure, that's a good point! Increments of 4us means we can fit 4ms is 10
>> bits, leaving plenty of space for ACK IDs (hopefully).
>
> If you do need more bits (e.g. to be on the safe side and have space for
> 8ms) you could also steal bits out of 'band' (we only need 3 I think)
> and 'hw_queue' (not sure what the limit really is, but there aren't many
> users, seems like only iwlwifi/dvm and hwsim care, and those certainly
> don't need >32 queues).
>
> Of course if you leave more bits for later that's good too ;-)

Yeah, let's leave that for later. After all, with the limits we
currently have configured, if a single packet takes up 4096 us, that
will trigger the per-station queue throttling in itself, so I think
we'll be fine (famous last words).

-Toke