Re: [PATCH] ath10k: remove iteration in wake_tx_queue

["Toke Høiland-Jørgensen" <toke@redhat.com>]

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