From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f44.google.com (mail-wm0-f44.google.com [74.125.82.44]) by dpdk.org (Postfix) with ESMTP id ABF6E354D for ; Fri, 12 Jan 2018 11:29:08 +0100 (CET) Received: by mail-wm0-f44.google.com with SMTP id r78so10904776wme.0 for ; Fri, 12 Jan 2018 02:29:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=bPVY605GSPsjrDnNnx5OrAS44r0Jv5gqlbHBtPcwnc8=; b=xVv4uqriEkOHpBRwqAPUDmNHn8gkrSY7n0w8bmdPatiF40npiUqXPkqH1auxZI7LQ9 u4uC8n6L0PcrcVDGzL9lNxHpr0PJQQwTlTByUb8sr4ZXE444J891udGb9wBlj7u+o9ix Wr556Fku+aQTfDjooN+ta2KSvtxpHkRG60lLZoAjYl9Do0qoIuBNYa6ksoPZCYiUCc8c cRhJ1ZVpDLVRg2N1UAmYzbxGLc0lwSNYq0aXB02bWEqpSWi51A0AqYuR8BfetnfAxZR2 A7Ghw05HpzGz1GnbeHwLaPTSG+a/IUUxUZRnMP/OMzgn7CR3WIcXQpwh8IoNi6JCf0f3 YKnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=bPVY605GSPsjrDnNnx5OrAS44r0Jv5gqlbHBtPcwnc8=; b=e1fgOFhx3M8W1v6iczvOOtOZvUJ4wuMRGKBSpEYaM/fC4fCC+1q4yw2po0qWh2LQbs DsSFdcMHQnKWBEppElHTp0TifJyKPjrrWDkMPnjshmNqTUSY/gq2JMJkhjtkz3AGPqNf unlvT/ZsOFtaYFH7jDrbSmFKdz81h95l5MBUbnY4DRpSCVzr9g90SaOXwkz5F8BrMlM0 jLKSmxcz7vJutxsGU3BJoLIb+XAAHQEhK1Gr3YzS7vdTyzM8XP0f8CLkfH7GVkpFzxA+ pQszHASwWSf7+wfsJehQEPW129B1a+2pJSwBSjgCyn4c1NkAl6CHXm2L49HgyHKgv8M4 lSSg== X-Gm-Message-State: AKwxyte35bjx7d5SwA7Z1+JoqhHU3GrNTjio46ihyjqIEcuZYcIv1KRy w34vBVtr7U8UtLBV7wRG1yizGlQo X-Google-Smtp-Source: ACJfBosBJbFuAkMgguz02P2YlC5p2K5MOvhqmUhSRyhi2ttqSXo94BMdQJ/EHoe5XMOOONxXX0ofWA== X-Received: by 10.80.163.136 with SMTP id s8mr5546033edb.162.1515752948343; Fri, 12 Jan 2018 02:29:08 -0800 (PST) Received: from bidouze.vm.6wind.com (host.78.145.23.62.rev.coltfrance.com. [62.23.145.78]) by smtp.gmail.com with ESMTPSA id k11sm4486336eda.22.2018.01.12.02.29.07 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 12 Jan 2018 02:29:07 -0800 (PST) Date: Fri, 12 Jan 2018 11:28:55 +0100 From: =?iso-8859-1?Q?Ga=EBtan?= Rivet To: Matan Azrad Cc: dev@dpdk.org Message-ID: <20180112102855.fmfggiaxutje5s4t@bidouze.vm.6wind.com> References: <1513703669-29363-1-git-send-email-matan@mellanox.com> <1513703669-29363-4-git-send-email-matan@mellanox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1513703669-29363-4-git-send-email-matan@mellanox.com> User-Agent: NeoMutt/20170113 (1.7.2) Subject: Re: [dpdk-dev] [PATCH v3 3/3] net/failsafe: improve Rx sub-devices iteration X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Jan 2018 10:29:08 -0000 Hi Matan, The other commits make sense to me so no issue there. I'm just surprised by this one so a quick question. On Tue, Dec 19, 2017 at 05:14:29PM +0000, Matan Azrad wrote: > Connecting the sub-devices each other by cyclic linked list can help to > iterate over them by Rx burst functions because there is no need to > check the sub-devices ring wraparound. > > Create the aforementioned linked-list and change the Rx burst functions > iteration accordingly. I'm surprised that a linked-list iteration, with the usual dereferencing, is better than doing some integer arithmetic. Maybe the locality of the referenced data helps. Anyway, were you able to count the cycles gained by this change? It might be interesting to do a measure with a CPU-bound bench, such as with a dummy device under the fail-safe (ring or such). MLX devices use a lot of PCI bandwidth, so the bottleneck could be masked in a physical setting. No comments otherwise, if you are sure that this is a performance gain, the implementation seems ok to me. Regards, -- Gaëtan Rivet 6WIND