[Codel] [RFC] ath10k: implement dql for htt tx
michal.kazior at tieto.com
Wed Mar 30 06:04:27 EDT 2016
On 30 March 2016 at 02:57, Dave Taht <dave.taht at gmail.com> wrote:
> As a side note of wifi ideas complementary to codel, please see:
> On Tue, Mar 29, 2016 at 12:49 AM, Michal Kazior <michal.kazior at tieto.com> wrote:
>> On the other hand DQL will react also to host system interrupt service
>> time. On slow CPUs (typically found on routers and such) you might end
>> up grinding the CPU so much you need deeper tx queues to keep the hw
>> busy (and therefore keep performance maxed). DQL should automatically
>> adjust to that while "txop limit" might not.
> Mmmm.... current multi-core generation arm routers should be fast enough.
While this helps it doesn't mean you can magically un-serialize
interrupt/txrx completion work.
>>>> To sum things up:
>>>> - DQL might be able to replace the explicit txop queue limiting
>>>> (which requires rate control info)
>>> I am pessimistic. Perhaps as a fallback?
>> At first I was (too) considering DQL as a nice fallback but the more I
>> think about the more it makes sense to use it as the main source of
>> deriving time slices for tx scheduling.
> I don't really get how dql can be applied per station in it's current forrm.
I was thinking of the following scheme:
- disable excessive retries in fw (apparently doable via WMI pdev parameter)
- deficit-based round-robin over stations
- maintain DQL structure per station
- when station gets its turn to xmit push frames to fw
- keep doing that (with regard to per station DQL limits) until either:
- associated software queue becomes empty
- 1 timeslice for given station has elapsed
- i was thinking of extracting timeslices from DQL or maintaining
- try next station
- do not submit packets to multiple stations at once (MU will need
more work..), i.e. always drain tx completely before switching to next
- each station may need a different timeslice (to squeeze out max
>>>> PS. I'm not feeling comfortable attaching 1MB attachment to a mailing
>>>> list. Is this okay or should I use something else next time?
>>> I/you can slam results into the github blogcerowrt repo and then pull
>>> out stuff selectively....
>> Good idea, thanks!
> You got commit privs.
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