Chenchong's work on net80211_ratectl

[Adrian Chadd]

Sweet, thanks!



-adrian



On 13 September 2013 09:11, Chenchong Qin <qinchenchong at gmail.com> wrote:

> Hi!
>
> Here is some updates.
>
> Another member is added to ieee80211_rc_info to record value of the
> maximum aggregate size. Then, in aggregation scenario, ratectl algo can
> inform aggregation selection code of proper maximum aggregate size.
>
> Per-vap ratectl statistics is exported through sysctl. When
> ieee80211_ratectl_init() is called, this statistics api is attached. It's
> convenient to implement the per-device api -- just traverse the vap list
> and call per-vap api for each vap. But, we know that ratectl of net80211
> provides service to vap-granularity object, not to device directly. So, is
> it more suitable to implement the per-device api in device driver (i.e.
> attach per-device api when attaching the device)?
>
> Code will be posted later.
>
> Thanks!
>
> Chenchong
>
>
> On Thu, Sep 12, 2013 at 2:05 AM, Adrian Chadd <adrian at freebsd.org> wrote:
>
>> Hi,
>>
>> For now, yes, you have to assume that you won't always get a response for
>> a rate lookup. The buffer may be sent with NOACK set, it may be deleted
>> during a channel change or scan, etc.
>>
>> And yes - the rate control lookup stuff for aggregate frames is a bit
>> messy. It would be nice for the rate control code to return the rate _and_
>> the maximum aggregate size, in case the aggregation selection wants to cap
>> how long frames are at the given choice.
>>
>>
>>
>> -adrian
>>
>>
>>
>> On 11 September 2013 10:29, Chenchong Qin <qinchenchong at gmail.com> wrote:
>>
>>> 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
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>