From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamal Hadi Salim Subject: qdisc running Date: Sun, 19 Oct 2014 15:24:42 -0400 Message-ID: <54440FFA.40307@mojatatu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: john Fastabend , Herbert Xu , "netdev@vger.kernel.org" , eric Dumazet To: Jesper Dangaard Brouer Return-path: Received: from mail-ie0-f178.google.com ([209.85.223.178]:63964 "EHLO mail-ie0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751495AbaJSTYt (ORCPT ); Sun, 19 Oct 2014 15:24:49 -0400 Received: by mail-ie0-f178.google.com with SMTP id rl12so3543420iec.9 for ; Sun, 19 Oct 2014 12:24:49 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: Jesper, You asked at the meeting the point to qdisc running. Original intent is to allow only one cpu to enter the lower half of the qdisc path. IOW, if one cpu was already in the qdisc then that guy could be used to dequeue packets. i.e this is good for batching. Original idea was Herbert's with major improvement from Eric and a small one from me. For history of different tried approaches look at: Look at slide 2: http://vger.kernel.org/netconf2011_slides/jamal_netconf2011.pdf then download the **amazing** flash animations which describe that history. http://vger.kernel.org/netconf2011_slides/netconf-2011-flash.tgz Follow the bullets in slide2 and map to the flash animations. If you go over them, you'll see it is still needed. I think someone oughta put those **amazing** animations on some website;-> cheers, jamal