From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felix Fietkau Date: Mon, 05 Apr 2010 16:40:08 -0700 Subject: [ath9k-devel] About A-MPDU aggregation. ATH_AMPDU_SUBFRAME_DEFAULT flag. In-Reply-To: References: Message-ID: <4BBA74D8.2010404@openwrt.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org On 2010-04-05 4:11 PM, Rakesh Kumar wrote: > Hi, > > I notice this parameter ATH_AMPDU_SUBFRAME_DEFAULT and in the code in > xmit.c, function ath_tx_form_aggr limits the number of sub-frames that > can be included in a A-MPDU to half the total size. The accompanying > comments say: > > /* do not exceed subframe limit */ > > But why halve the baw_size for that? I looked around the standard > documents, couldn't find any reference to halving the station-specfic > baw_size (negotiated during association) to half. Maybe because ath9k tries to keep two A-MPDU aggregates in the xmit queue and has to handle retransmission of failed subframes in software. IMHO it makes sense to use half of the BAW for each of the queue entries under those conditions. - Felix