From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f47.google.com (mail-wm0-f47.google.com [74.125.82.47]) by dpdk.org (Postfix) with ESMTP id 6B4C65908 for ; Tue, 3 May 2016 11:50:44 +0200 (CEST) Received: by mail-wm0-f47.google.com with SMTP id a17so28810188wme.0 for ; Tue, 03 May 2016 02:50:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind-com.20150623.gappssmtp.com; s=20150623; h=subject:to:references:cc:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding; bh=mWpp//J9FkCMbPKyPQJZ6yFel0jLmiFPu1U/dItaedM=; b=PNQe2b49b36qFJWTcnjEx8CHL3jQ0Sdhmom2v53ty3L2+Eq0krDNq4QZ4GpVukDjut 4yYHzTX1uMrgfog3TvrzhsH6xl66jNBg5rs+V39Q4qoTG7rNuk0lZxApbK1sUBBLbYtw I/M2heF64BhOf2TVumGSJPVCErIfiGmqw0wuKeqey2Bb+sgOyCRhJ5i8L+3KcLejhMS2 Q4D1Qg1LNW2yv4T4yoKuhtF5eUGzEr6ZqN8cDsSsLbWo9HHZlY/h4/ZOtg0pky93Bccs 1TRu00p87k4gNTofVml5bpt44lWzTOP8z0hJiUf5bwNRDYc4tth4tt29Hgb4JLzKXaEL XNag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:cc:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=mWpp//J9FkCMbPKyPQJZ6yFel0jLmiFPu1U/dItaedM=; b=RaR1eAVq2u0PEartZFP634WZM8C1Dv1qc2uNFivea+kf0B9MYC3vrU2oAwvWnDz28G 6sINzVjl7v2eQMiAc2R/t6JLBcIvxuD2fbVYzCXiMpP7fGj5gPgekfi4+edd317hDh7Z 2fiF4354fNO09IGgBJafI+tyU//A60XKvbdHueFLju/DieENH7RoLrAVh6RPmb7Provn wIcTkXkMhfet4ce2BgSQwoztB2Tc/eDPKoBF9wXrpyA97JJxx2wi2ZpwdYYV6K4sIvjn pYOO92WTHOqlW1+oInUEqWAPw9Kq+p6m/kxj884e05JczLiE5LKKrMVpXp4Gb+xqyrGT lROw== X-Gm-Message-State: AOPr4FX9WwNYfj160A0gT8kOigGSdPKgjy+gZoFVrr15cmUhpTbWjqEoxon6HuUaf7cjuXtI X-Received: by 10.28.105.200 with SMTP id z69mr2295027wmh.78.1462269044284; Tue, 03 May 2016 02:50:44 -0700 (PDT) Received: from [10.16.0.189] (guy78-3-82-239-227-177.fbx.proxad.net. [82.239.227.177]) by smtp.gmail.com with ESMTPSA id f135sm3452899wmf.22.2016.05.03.02.50.42 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 03 May 2016 02:50:43 -0700 (PDT) To: Bruce Richardson , Jerin Jacob References: <1462190377-26865-1-git-send-email-jerin.jacob@caviumnetworks.com> <20160503094516.GC21300@bricha3-MOBL3> Cc: dev@dpdk.org, pablo.de.lara.guarch@intel.com From: Ivan Boule Message-ID: <57287467.7080702@6wind.com> Date: Tue, 3 May 2016 11:50:31 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.7.0 MIME-Version: 1.0 In-Reply-To: <20160503094516.GC21300@bricha3-MOBL3> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH] app/testpmd: add packet data prefetch in macswap loop X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 03 May 2016 09:50:44 -0000 On 05/03/2016 11:45 AM, Bruce Richardson wrote: > On Mon, May 02, 2016 at 05:29:37PM +0530, Jerin Jacob wrote: >> prefetch the next packet data address in advance in macswap loop >> for performance improvement. >> >> ... >> for (i = 0; i < nb_rx; i++) { >> + if (likely(i < nb_rx - 1)) >> + rte_prefetch0(rte_pktmbuf_mtod(pkts_burst[i + 1], >> + void *)); > > At least on IA platforms, there is no issue with prefetching beyond the end of > the array, since it's only a hint to the cpu. If this is true for other platforms, > then I suggest we just drop the conditional and just always prefetch. This is an interesting point. Bruce, are you suggesting that prefetching at an invalid [virtual] address won't trigger a CPU exception? Ivan > > /Bruce > >> mb = pkts_burst[i]; >> eth_hdr = rte_pktmbuf_mtod(mb, struct ether_hdr *);