On 2016-11-27 16:58, Toke Høiland-Jørgensen wrote:
> "Valo, Kalle" <kvalo@xxxxxxxxxxxxxxxx> writes:
>
>> (The make-wifi-fast list is annoying as it always spams me when it's on
>> CC, so dropped it.)
>>
>> Toke Høiland-Jørgensen <toke@xxxxxxx> writes:
>>
>>> This reworks the ath9k driver to schedule transmissions to connected
>>> stations in a way that enforces airtime fairness between them. It
>>> accomplishes this by measuring the time spent transmitting to or
>>> receiving from a station at TX and RX completion, and accounting this to
>>> a per-station, per-QoS level airtime deficit. Then, an FQ-CoDel based
>>> deficit scheduler is employed at packet dequeue time, to control which
>>> station gets the next transmission opportunity.
>>>
>>> Airtime fairness can significantly improve the efficiency of the network
>>> when station rates vary. The following throughput values are from a
>>> simple three-station test scenario, where two stations operate at the
>>> highest HT20 rate, and one station at the lowest, and the scheduler is
>>> employed at the access point:
>>>
>>> Before / After
>>> Fast station 1: 19.17 / 25.09 Mbps
>>> Fast station 2: 19.83 / 25.21 Mbps
>>> Slow station: 2.58 / 1.77 Mbps
>>> Total: 41.58 / 52.07 Mbps
>>>
>>> The benefit of airtime fairness goes up the more stations are present.
>>> In a 30-station test with one station artificially limited to 1 Mbps,
>>> we have seen aggregate throughput go from 2.14 to 17.76 Mbps.
>>>
>>> Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxx>
>>
>> [...]
>>
>>> +void ath_acq_lock(struct ath_softc *sc, struct ath_acq *acq)
>>> + __acquires(&acq->lock)
>>> +{
>>> + spin_lock_bh(&acq->lock);
>>> +}
>>> +
>>> +void ath_acq_unlock(struct ath_softc *sc, struct ath_acq *acq)
>>> + __releases(&acq->lock)
>>> +{
>>> + spin_unlock_bh(&acq->lock);
>>> +}
>>
>> Why these? To me it looks like they just add an extra function jump and
>> unneccessary extra layer.
>
> Well, there's already similar functions for the txq lock (ath_txq_lock()
> and ath_txq_unlock() in xmit.c), so figured I'd be consistent with
> those. And also that the __acquires and __releases macros were probably
> useful.
>
> Also, won't the compiler automatically inline them?
Not necessarily, these functions are not static. I think it would be a
good idea to turn the ath_txq_lock/unlock functions into static inline
functions as well.
Please don't blindly repeat patterns that are already there, some of
them might just not make any sense at all ;)
- Felix
