Re: iwlwifi aggregation info

Tomas Winkler
2008-07-30T16:08:00Z

On Wed, Jul 30, 2008 at 6:19 PM, Johannes Berg
<johannes@sipsolutions.net> wrote:
> On Wed, 2008-07-30 at 16:59 +0300, Tomas Winkler wrote:
>
>> > Well qdiscs don't just do that, depending on the configuration, so we
>> > shouldn't rely on them doing just that.
>>
>> I know but this was the primary purpose of MQ to push the scheduling
>> decision to HW if I'm not mistaken.
>
> I thought it was more about the upper level locking, ethernet hw really
> just round-robins most of the time. Although it will, of course, be used
> for scheduling decisions.
>
> Is aggregation really a scheduling decision though?
>
>> We really don't need anything else just queueing.
>
> Exactly, but qdiscs do most definitely not provide just queueing, and we
> should not deprive the user of the ability to use qdiscs on wireless.
>
>> For example what the
>> prioritization which is done in current wme.c
>> is wrong and it won't pass certification and creates starvation.
>> Tested and proved.
>
> Can you explain how starvation happens? In what scenarios? With or
> without aggregation?

for (queue = 0; queue < QD_NUM(hw); queue++)

This always starts 0 prioritize dequeue the first frame. But what we
need is RR and let HW to prioritize the transmission according AC
Tomas