[ath9k-devel] Fwd: How to lock AMPDU length at a specific value?

[Ali Abedi <a2abedi@uwaterloo.ca>]

Using a constant rate does not help (I am already doing this). When I 
set the limit to 20 for example, I get any number between
1 to 20 for the number of aggregated frames. This is probably because 
when we want to start the transmission
we don't always have 20 frames to aggregate so the card aggregates all 
it already has
in the queue ready for transmission. So how can we wait to have 20 
frames ready for transmission so that
all aggregate frames carry exactly 20 frames (constant rate)?

Thank you,
Ali


On 21/01/2014 15:59, Kamran Nishat wrote:
>
>
>
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> do it at a fix rate  (1st check if duration of packet is less tahn 4ms 
> for ur MCS) and with nearly zero noise losses.
>
> Kamran
>
>
> On Wed, Jan 22, 2014 at 1:54 AM, Ali Abedi <a2abedi@uwaterloo.ca 
> <mailto:a2abedi@uwaterloo.ca>> wrote:
>
>     These mostly determine the MAX AMPDU length. I also want to
>     determine the minimum length, so
>     that I can set min=max and lock the AMPDU length.
>
>     Thank you,
>     Ali
>
>     On 21/01/2014 15:07, Kamran Nishat wrote:
>>     As far as i know AMPDU length is determined by 3 constraints.
>>     Firs maximum AMPDU length. second blockAck window (if there were
>>     losses then this will play a role).  Third is Max air time of the
>>     AMPDU which is 4ms for some domain constraints. this comes into
>>     play MCS is low and packet duration gets more than 4ms. See
>>     following function in xmit.c for details
>>     ath_tx_form_aggr  <http://lxr.free-electrons.com/ident?i=ath_tx_form_aggr>  
>>
>>
>>     On Tue, Jan 21, 2014 at 11:49 PM, Ali Abedi <a2abedi@uwaterloo.ca
>>     <mailto:a2abedi@uwaterloo.ca>> wrote:
>>
>>         Hello,
>>
>>         I have seen questions regarding the length of an AMPDU and
>>         how to change
>>         the maximum AMPDU length.
>>         However, I require to lock the AMPDU length at a specific value.
>>         Changing the max length does not guarantee
>>         that all AMPDUs have a fixed length, it can be anything
>>         between 1 to max
>>         based on the rate of arrival of new frames.
>>         Is there a mechanism to force the card to wait to have enough
>>         frames so
>>         that all AMPDUs have a fixed length that we specify? In other
>>         words, I
>>         need all AMPDUs to aggregate X full length frames.
>>
>>         Thank you,
>>         Ali
>>
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>>
>>
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>
>
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