From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from nbd.name ([46.4.11.11]:53670 "EHLO nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755742Ab1HaOrJ (ORCPT ); Wed, 31 Aug 2011 10:47:09 -0400 Message-ID: <4E5E4967.8070401@openwrt.org> (sfid-20110831_164717_105640_BCBD1066) Date: Wed, 31 Aug 2011 16:47:03 +0200 From: Felix Fietkau MIME-Version: 1.0 To: Johannes Berg CC: linux-wireless@vger.kernel.org, linville@tuxdriver.com, Helmut Schaa Subject: Re: [PATCH] mac80211: retry sending failed BAR frames later instead of tearing down aggr References: <1314558661-28454-1-git-send-email-nbd@openwrt.org> <1314792948.4161.23.camel@jlt3.sipsolutions.net> In-Reply-To: <1314792948.4161.23.camel@jlt3.sipsolutions.net> Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 2011-08-31 2:15 PM, Johannes Berg wrote: > On Sun, 2011-08-28 at 21:11 +0200, Felix Fietkau wrote: >> Unfortunately failed BAR tx attempts happen more frequently than I >> expected, and the resulting aggregation teardowns cause performance >> issues, as the aggregation session does not always get re-established >> properly. > > I find this curious. How can tons of traffic go through, but BAR frames > fail? These are unicast and should be retried a bunch... I think it mostly happens when the client goes to powersave (triggered by background scans, etc). >> Instead of tearing down the entire aggr session, we can simply store the >> SSN of the last failed BAR tx attempt, wait for the first successful >> tx status event, and then send another BAR with the same SSN. > > So what if it keeps failing? I think eventually we'd want to kill the > session? If it keeps failing, then the connection is probably so bad that it doesn't matter if we kill the session or not. - Felix