From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from nbd.name (nbd.name [IPv6:2a01:4f8:131:30e2::2]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id CFE9F3B25D for ; Tue, 6 Sep 2016 18:04:05 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=nbd.name; s=20160729; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:To:Subject; bh=GpcuTXfglddrldmpr6+e+tJh+DpwZBI27Xs3nmMwdDY=; b=g7SZFuKf4e/uibbj+j2z3dEPZCXbcrdImjM5ipO3/ovuN6R6eHDwcM1wY6qIooSvQ2sz5ox02Wz9NBjR+QVsjUhgEfdv6inNkdmGasKCTDOmIC68eSfmzQW7yVi1eHjXdHXiWhf3xzcel1l9y+JEfBI1xPKtTWhc7Wuh74qC+DU=; To: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , make-wifi-fast@lists.bufferbloat.net, linux-wireless@vger.kernel.org References: <20160905113042.22271-1-toke@toke.dk> <20160906114426.25520-1-toke@toke.dk> From: Felix Fietkau Message-ID: <9063eae7-53c7-a1c0-c973-9dc519cf66cd@nbd.name> User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <20160906114426.25520-1-toke@toke.dk> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Mon, 28 Nov 2016 08:47:10 -0500 Subject: Re: [Make-wifi-fast] [PATCH v8] mac80211: Move reorder-sensitive TX handlers to after TXQ dequeue. X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Date: Tue, 06 Sep 2016 22:04:05 -0000 X-Original-Date: Wed, 7 Sep 2016 00:04:02 +0200 X-List-Received-Date: Tue, 06 Sep 2016 22:04:05 -0000 On 2016-09-06 13:44, Toke Høiland-Jørgensen wrote: > The TXQ intermediate queues can cause packet reordering when more than > one flow is active to a single station. Since some of the wifi-specific > packet handling (notably sequence number and encryption handling) is > sensitive to re-ordering, things break if they are applied before the > TXQ. > > This splits up the TX handlers and fast_xmit logic into two parts: An > early part and a late part. The former is applied before TXQ enqueue, > and the latter after dequeue. The non-TXQ path just applies both parts > at once. > > Because fragments shouldn't be split up or reordered, the fragmentation > handler is run after dequeue. Any fragments are then kept in the TXQ and > on subsequent dequeues they take precedence over dequeueing from the FQ > structure. > > This approach avoids having to scatter special cases for when TXQ is > enabled, at the cost of making the fast_xmit and TX handler code > slightly more complex. > > Signed-off-by: Toke Høiland-Jørgensen Acked-by: Felix Fietkau