From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-vk0-x22c.google.com ([2607:f8b0:400c:c05::22c]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1axaUV-0006VN-Av for ath10k@lists.infradead.org; Tue, 03 May 2016 13:35:55 +0000 Received: by mail-vk0-x22c.google.com with SMTP id m188so23335255vka.1 for ; Tue, 03 May 2016 06:35:34 -0700 (PDT) Message-ID: <1462282531.5535.307.camel@edumazet-glaptop3.roam.corp.google.com> Subject: Re: [Codel] fq_codel_drop vs a udp flood From: Eric Dumazet Date: Tue, 03 May 2016 06:35:31 -0700 In-Reply-To: <7A2801D5E40DD64A85E38DF22117852CD09A1873@wdc1exchmbxp01.hq.corp.viasat.com> References: <1462125592.5535.194.camel@edumazet-glaptop3.roam.corp.google.com> <865DA393-262D-40B6-A9D3-1B978CD5F6C6@gmail.com> <7A2801D5E40DD64A85E38DF22117852CD09A181F@wdc1exchmbxp01.hq.corp.viasat.com> <7A2801D5E40DD64A85E38DF22117852CD09A1873@wdc1exchmbxp01.hq.corp.viasat.com> Mime-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "ath10k" Errors-To: ath10k-bounces+kvalo=adurom.com@lists.infradead.org To: "Agarwal, Anil" Cc: Jonathan Morton , "codel@lists.bufferbloat.net" , Dave Taht , ath10k , "make-wifi-fast@lists.bufferbloat.net" On Tue, 2016-05-03 at 12:50 +0000, Agarwal, Anil wrote: > I should be more precise about the statement about the inaccuracy of the algorithm. > Given that we dequeue packets in round robin manner, the maxqidx value may, on occasions, point to a queue > which is smaller than the largest queue by up to one MTU. That is not true. Linux qdiscs (fq_codel being one of them) can carry big packets, up to 64KB in size. You can not assume GRO/GSO are disabled. We absolutely want them for high performance. There is no way fq_codel will track in real time the biggest flow 'just in case we have to drop packets at enqueue()' This is a conscious choice I made years ago. This patch will fix the performance issue and keep the normal operations fast. https://patchwork.ozlabs.org/patch/617307/ _______________________________________________ ath10k mailing list ath10k@lists.infradead.org http://lists.infradead.org/mailman/listinfo/ath10k