Chenchong's work on net80211_ratectl

[Chenchong Qin]

Hi!

I've added some aggregation support here!

At first I intend to pass subframe informations(nframes, per-subframe
length etc.)
to the ratectl api. But it seems to be a paradox that rate lookup must be
performed
before the ampdu is formed (aggregation limit based on the rate control
decision
is need) and subframe informations can be obtain only after the ampdu is
formed.
So, I add a new ieee80211_rc_info flag to ieee80211_ratectl to let it
distinguish
aggregation and non-aggregation scenarios. If rate lookup is called in an
aggregation
scenario, this flag is set. Then, ratectl algo knows that it's now finding
rates for an
ampdu and the framelen which records len of the first frame can be ignored.
When
it comes to complete period, tx status that shows number of subframes been
sent
and number of subframes been successfully received is passed to the ratectl
api.

I also get a question here - whether one tx that doesn't perform rate
lookup will call
the complete procedure?

Thanks!

Chenchong


On Sun, Sep 8, 2013 at 11:18 PM, Chenchong Qin <qinchenchong at gmail.com>wrote:

> Hi!
>
> I've added the common ratectl state as an mbuf tag!
>
> After days of frustration (compile errors, boot failed, kernel panics,
> suddenly kernel freezing...), it seems that ath now can use 11n-aware
> net80211 ratectl api to do rate control. Attachment[0] is the diff of
> modifications to dev/ath. Changes to net80211 is minor this time. Just add
> some debug msgs to it. Please reference my gsoc svn repo<https://svnweb.freebsd.org/socsvn/soc2013/ccqin/head/>
> .
>
> It's worth mentioning that sometimes the kernel will "freezing" (it looks
> like all things stop working, screen is freezing, keyboard and mouse are
> not responding) after wireless stuff start working for a while. At first, I
> consider it caused by my modification to ath. But this strange thing can
> also happen in a head kernel (r255382). Attachment[1] is some useful
> messages just before it happens. By the way, I use a AR9227 device.
>
> And, I found that, for aggregation scenario, ath gathers tx information
> and update the ratectl states. So, what we can do to net80211 to let it
> support aggregation?
>
> Thanks!
>
> Chenchong
>
>
> On Tue, Sep 3, 2013 at 9:29 AM, Chenchong Qin <qinchenchong at gmail.com>wrote:
>
>> OK!
>>
>> Thanks! :-)
>>
>> Chenchong
>>
>>
>> On Tue, Sep 3, 2013 at 1:56 AM, Adrian Chadd <adrian at freebsd.org> wrote:
>>
>>> Hi!
>>>
>>> You can declare an mbuf tag and use that. Look at M_TXCB in net80211 and
>>> how mbuf tags are added.
>>>
>>> I've long thought about adding a net80211 mbuf tag to represent -all- of
>>> the tx related state - TX callback, rate control, rate completion,
>>> aggregation state, retry count, etc. That way all the drivers can use it.
>>>
>>>
>>>
>>> -adrian
>>>
>>>
>>
>
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