Re: [PATCH] ath10k: remove iteration in wake_tx_queue

[Erik Stromdahl <erik.stromdahl@gmail.com>]

On 4/16/19 9:07 PM, Toke Høiland-Jørgensen wrote:
> Erik Stromdahl <erik.stromdahl@gmail.com> writes:
> 
>> On 4/1/19 1:05 PM, Toke Høiland-Jørgensen wrote:
>>> Erik Stromdahl <erik.stromdahl@gmail.com> writes:
>>>
>>>> Iterating the TX queue and thereby dequeuing all available packets in the
>>>> queue could result in performance penalties on some SMP systems.
>>>>
>>>> The reason for this is most likely that the per-ac lock (active_txq_lock)
>>>> in mac80211 will be held by the CPU iterating the current queue.
>>>>
>>>> This will lock up other CPUs trying to push new messages on the TX
>>>> queue.
>>>>
>>>> Instead of iterating the queue we fetch just one packet at the time,
>>>> resulting in minimal starvation of the other CPUs.
>>>
>>> Did you test this with Felix' patches reducing the time the lock is held
>>> in mac80211?
>>>
>>> -Toke
>>>
>> Hi Toke,
>>
>> I am not aware of these patches. Can you please point them out for me?
> 
> They've already been merged. Commits dcec1d9bc8a7 and 7ef769459f14 in
> mac80211-next :)
> 
> -Toke
> 

I see. I am using the ath tree and I couldn't find them there.
I can cherry-pick them to my own tree and try them out
(or wait until Kalle updates ath.git).

--
Erik