From: Felix Fietkau <nbd@openwrt.org>
To: voncken <cedric.voncken@acksys.fr>, linux-wireless@vger.kernel.org
Subject: Re: ATH9K software retry
Date: Thu, 06 Feb 2014 17:56:06 +0100 [thread overview]
Message-ID: <52F3BEA6.1080502@openwrt.org> (raw)
In-Reply-To: <009301cf2359$e35f0330$aa1d0990$@acksys.fr>
On 2014-02-06 17:38, voncken wrote:
>> -----Message d'origine-----
>> De : Felix Fietkau [mailto:nbd@openwrt.org]
>> Envoyé : jeudi 6 février 2014 15:42
>> À : Cedric VONCKEN; linux-wireless@vger.kernel.org
>> Objet : Re: ATH9K software retry
>>
>> On 2014-02-06 14:06, Cedric VONCKEN wrote:
>> > In xmit.c the function ath_tx_complete_aggr test if the fi->retries <
>> > ATH_MAX_SW_RETRIES.
>> >
>> > If this condition is true, ATH9K handle software retry.
>> >
>> > Minstrel set in the frame one or more rates, for each rate minstrel
>> > set a retries count. I think is sufficient.
>> >
>> > Why ATH9K need to manage the software retries?
>> The retries configured for minstrel_ht are used for hardware retries of
> single
>> frames and full A-MPDU transmissions. Software retries are used for
>> individual subframes that are sent as part of A-MPDUs.
>> This is required, because failed subframes are frequent with higher MCS
> rates
>> and A-MPDU.
>>
> Is it possible to only applied software retrying for A-MPDU frame with more
> one frame?
> If I correctly understood the code, the function ath_tx_count_frames return
> the number of frame in the A-MPDU. If nframes == 1 we don't use the software
> retry.
Software retry should be applied to any frame that is part of a BlockAck
session, because any failed frame that is not retried requires the
sender to notify the receiver with a BlockAckRequest, which is
expensive. I would suggest keeping the current behavior, unless you have
a good reason to change it and understand the implications.
- Felix
next prev parent reply other threads:[~2014-02-06 16:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-06 13:06 ATH9K software retry Cedric VONCKEN
2014-02-06 14:42 ` Felix Fietkau
2014-02-06 16:38 ` voncken
2014-02-06 16:56 ` Felix Fietkau [this message]
2014-02-06 17:59 ` voncken
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