Subject: Re: [RFC] mac80211: Re-enable aggregation
From: Johannes Berg <johannes@sipsolutions.net>
To: Sujith <Sujith.Manoharan@atheros.com>
Cc: "linville@tuxdriver.com" <linville@tuxdriver.com>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
	Luis Rodriguez <Luis.Rodriguez@Atheros.com>,
	"tomasw@gmail.com" <tomasw@gmail.com>
In-Reply-To: <18684.20459.335157.171344@gargle.gargle.HOWL>
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	 <1224491480.18024.32.camel@johannes.berg>
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Date: Mon, 20 Oct 2008 11:38:50 +0200
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On Mon, 2008-10-20 at 15:01 +0530, Sujith wrote:
> Johannes Berg wrote:
> > Can you change your quote string from " > " to "> "? Just asking, if yo=
u
> > can't/don't want to that's fine, it just always confuses me for a
> > second. I really should try to figure out if I can convince my mailer t=
o
> > highlight " > " indented text as quote too.
>=20
> Sure, adding (setq vm-included-text-prefix "> ") in my .emacs did the tri=
ck. :)

Thanks! :)

> > > Well, currently ath9k maintains a buffer list for each tid.
> > > When mac80211 sends down a frame, if the recipient has an aggr. sessi=
on going,
> > > it is appended to the tid's buffer list. Non-HT frames are sent out i=
mmediately.
> >=20
> > Incidentally, why the distinction between HT and non-HT frames?
>=20
> HT frames for aggregation enabled STAs are processed in the TX completion=
 path, so
> they are buffered.

But couldn't non-HT frames be buffered similarly? Maybe I'm missing one
of the finer points of the 11n draft?

> > > On TX completion, we run through all the ACs, STAs and TIDs and send =
out pending
> > > frames as aggregates.
> >=20
> > So basically you can always have one frame or one aggregation
> > "pack" (for lack of a better word) queued to the hw?
> >=20
>=20
> I am not sure, I should check.

Doesn't really matter, I was just trying to make sense out of your
statement of processing it at completion time.

> Makes sense, ath9k currently has a similar set of functions ( pausing/res=
uming TIDs).
> How would the pending frames for each TID be managed ?
> Will the driver be able to pull them as and when needed or would mac80211
> push them down on checking if the TID is awake ?

I guess there's no clear answer here. How about "whichever you want"?
Though I think I prefer pushing them down as that makes the model easier
to understand. It probably also makes the Intel case easier to
implement.

johannes

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