Chenchong's work on net80211_ratectl

[Adrian Chadd]

Sweet!

Does this work on your AR9227? Can you provide some example output?


-a


On 14 September 2013 21:08, Chenchong Qin <qinchenchong at gmail.com> wrote:

> Hi!
>
> Yes, a call to ieee80211_ratectl_rc_info_set() is needed. To make other
> drivers work, the __init__ and __findrate__ parts also need to be adapted.
> When initialize the ratectl state, a cap flag must be properly set and
> feed to ieee80211_ratectl_init().  __findrate__ part should be repalced
> with our
> ieee80211_ratectl_rates().
>
> I've added  ieee80211_ratectl_rc_info_get() to be used to get the
> ieee80211_rc_info. If found the tag, use it; if not, add a new one and use
> it. Then we don't
> need to free it explicitly (the tag is freed when associated mbuf is freed)
> and this interface is unified to both __findrate__ and __complete__.
>
> Thanks!
>
> Chenchong
>
>
> On Sat, Sep 14, 2013 at 11:21 PM, Adrian Chadd <adrian at freebsd.org> wrote:
>
>> Ah, cool! I see you've only just made the other drivers compile; what's
>> required to make them work? i guess a call
>> to ieee80211_ratectl_rc_info_set() ?
>>
>> Maybe you should add a ieee80211_ratectl_rc_info_set_mbuf() helper that
>> does the "lookup tag; if one exists use it else use a temporary one" code
>> that you put in if_ath.c, if_ath_tx.c.
>>
>> Other than that, this is looking very good! thankyou!
>>
>>
>> -adrian
>>
>>
>>
>> On 13 September 2013 20:52, Chenchong Qin <qinchenchong at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> Here is latest update. Per-device ratectl statistics is implemented in
>>> ath and attached when ath is attaching.
>>>
>>> Thanks!
>>>
>>> Chenchong
>>>
>>>
>>> On Sat, Sep 14, 2013 at 3:37 AM, Adrian Chadd <adrian at freebsd.org>wrote:
>>>
>>>> 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
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>