Received-SPF: pass (google.com: best guess record for domain of linux-wireless-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
To:     Justin Capella <justincapella@gmail.com>,
        Johannes Berg <johannes@sipsolutions.net>
Cc:     linux-wireless@vger.kernel.org
Subject: Re: [PATCH 1/2] mac80211: Turn AQL into an NL80211_EXT_FEATURE
In-Reply-To: <CAMrEMU9t-Ed9ASyjGcJvpKM=Japiy0fv_cd1_3D5Sy_UMte_9A@mail.gmail.com>
References: <20191211145230.200132-1-toke@redhat.com> <20191211145230.200132-2-toke@redhat.com> <df7eb0b71dc9cfdc7d9b5f7abdbcce0d42fa4a1e.camel@sipsolutions.net> <CAMrEMU9t-Ed9ASyjGcJvpKM=Japiy0fv_cd1_3D5Sy_UMte_9A@mail.gmail.com>
Date:   Thu, 12 Dec 2019 11:29:55 +0100
Message-ID: <871rt9g7ks.fsf@toke.dk>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

Justin Capella <justincapella@gmail.com> writes:

> Disclaimer: I'm new, so don't assume my questions are rhetorical...
>
> sta = container_of(txq->sta, struct sta_info, sta); // Is this
> correct?

Not sure what you're referring to here; but generally, yes? :)

> I see the use of IEEE80211_NUM_ACS seems to be standard, is that AC
> specific? I learned today that different devs have different numbers
> of queues...

AC numbers are defined in the standard, and there are always four of
them. Different hardware can have different numbers of queues, which may
or may not be related to NUM_ACS.

> What are the units of the THRESHOLD, iirc there was some bit
> shifting/masking?

Units are logically microseconds, but stored as increments of 4
microseconds because we ran out of bits; this is kept inside the
setter/getter function, though, so everywhere else is just microseconds.

> Is there supposed to be a queue per station, or just per interface?

There's a TXQ per TID (so 16 per station), and an additional one on the
interface for multicast.

> It seemed like the threshold was meant to pick a higher or lower
> queue, this seems to maybe just reject if not within the bounds?

There are two thresholds; one for the whole interface, and one per
station. If either is exceeded transmission will be throttled.

-Toke