2014-09-18 12:47:29

by Cedric DEBARGE

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Subject: RE: [PATCHv2 00/10] add support for ACK timeout estimation in ath9k driver

On Tue, Sept 16, 2014 at 02:13:25AM +0200, Lorenzo Bianconi wrote:

Hi,

> This patchset adds support for estimation of the ACK timeout (dynack) in ath9k driver. Ath9k dynack computes the > ACK timeout based on ACK frame RX timestamp, TX frame timestamp and frame duration.
>
> Ath9k dynack has been tested in indoor environment using AR9223/AR9280 chipset (running 3.17.0-rc5 kernel), on
> 9Km PtoP link using AR9280 chipset (running OpenWRT trunk, compat-wireless-2014-05-22) and on an AP using AR9280 > chipset (running OpenWRT trunk, compat-wireless-2014-05-22) serving 35 STA with links up to 8Km

During your indoor tests, did you managed to get precise enough timestamps to compute a significant ACK to (despite of short distances and multipaths)?

Previous tests have shown impressive bandwith gains (10% on a 9Km P2P link). Did you also get improvements in indoor environment?

Thanks,

C?dric DEBARGE


2014-09-18 18:47:49

by Lorenzo Bianconi

[permalink] [raw]
Subject: Re: [PATCHv2 00/10] add support for ACK timeout estimation in ath9k driver

> On Tue, Sept 16, 2014 at 02:13:25AM +0200, Lorenzo Bianconi wrote:
>
> Hi,
>

Hi,

>> This patchset adds support for estimation of the ACK timeout (dynack) in ath9k driver. Ath9k dynack computes the > ACK timeout based on ACK frame RX timestamp, TX frame timestamp and frame duration.
>>
>> Ath9k dynack has been tested in indoor environment using AR9223/AR9280 chipset (running 3.17.0-rc5 kernel), on
>> 9Km PtoP link using AR9280 chipset (running OpenWRT trunk, compat-wireless-2014-05-22) and on an AP using AR9280 > chipset (running OpenWRT trunk, compat-wireless-2014-05-22) serving 35 STA with links up to 8Km
>
> During your indoor tests, did you managed to get precise enough timestamps to compute a significant ACK to (despite of short distances and multipaths)?
>

Dynack tx/rx timestamps are snapshots of PCU's timestamps (expressed
in TSF value).

> Previous tests have shown impressive bandwith gains (10% on a 9Km P2P link). Did you also get improvements in indoor environment?
>

In indoor environment I got the same performance obtained with a
static ACK timeout since LER was roughly 0%. Anyway I guess dynack
should be enabled just on outdoor "long" links (like ones tested by
Philippe) since that environment is really sensitive to ACK timeout.

> Thanks,
>
> Cédric DEBARGE

Regards,
Lorenzo

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