From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6A05C43381 for ; Sun, 24 Mar 2019 01:54:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75A0320685 for ; Sun, 24 Mar 2019 01:54:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727822AbfCXByE (ORCPT ); Sat, 23 Mar 2019 21:54:04 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:35328 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727706AbfCXByE (ORCPT ); Sat, 23 Mar 2019 21:54:04 -0400 Received: from localhost (unknown [50.233.106.125]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 9E03814B479CE; Sat, 23 Mar 2019 18:54:03 -0700 (PDT) Date: Sat, 23 Mar 2019 21:54:03 -0400 (EDT) Message-Id: <20190323.215403.340785854005311185.davem@davemloft.net> To: pabeni@redhat.com Cc: netdev@vger.kernel.org, edumazet@google.com, john.fastabend@gmail.com, ivecera@redhat.com Subject: Re: [PATCH net-next v3 0/2] net: dev: BYPASS for lockless qdisc From: David Miller In-Reply-To: References: X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sat, 23 Mar 2019 18:54:03 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Paolo Abeni Date: Fri, 22 Mar 2019 16:01:54 +0100 > This patch series is aimed at improving xmit performances of lockless qdisc > in the uncontended scenario. > > After the lockless refactor pfifo_fast can't leverage the BYPASS optimization. > Due to retpolines the overhead for the avoidables enqueue and dequeue operations > has increased and we see measurable regressions. > > The first patch introduces the BYPASS code path for lockless qdisc, and the > second one optimizes such path further. Overall this avoids up to 3 indirect > calls per xmit packet. Detailed performance figures are reported in the 2nd > patch. > > v2 -> v3: > - qdisc_is_empty() has a const argument (Eric) > > v1 -> v2: > - use really an 'empty' flag instead of 'not_empty', as > suggested by Eric Looks great, series applied, thanks Paolo.