From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f52.google.com (mail-wm0-f52.google.com [74.125.82.52]) by dpdk.org (Postfix) with ESMTP id F0D1D2BD6 for ; Sun, 20 Mar 2016 11:35:12 +0100 (CET) Received: by mail-wm0-f52.google.com with SMTP id p65so89564172wmp.0 for ; Sun, 20 Mar 2016 03:35:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:organization:user-agent :in-reply-to:references:mime-version:content-transfer-encoding; bh=WXGGZGAm0qESoT24e7xmvrVJCEnp8eVjFcZFkIBQz7o=; b=PK5qO4pM4tdQEDYFzKlXkukgOKsGA2wWx09joKCcUvOuhe9qgKeDyv/d8HTr81JYWp JrcXAn7SmNXFhH+B5BSpIv9JWD1ArLR4LwMicX0es7w8mCd5kGf9GTZwRV3vrcYV0zVt QKWCUNtzwQy4sF5yFaLVq8CndhFhUvbeULlJhkXatuFOIkUHCZD7KuVuZguK3Ab82s9f +tE5So2G2+b6yNe1MrLpIDQJOCgixPb3wQW9mJDzYeFJgOokNQ9XhpVfSIYYj8Ejbl4c V3sZ0xR689KUCTAxBRzuw9ni8D7JRJ9koZjHXLyWL+uU5RNiGh4uzXawhDCMLmqi9/YZ L4bA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:organization :user-agent:in-reply-to:references:mime-version :content-transfer-encoding; bh=WXGGZGAm0qESoT24e7xmvrVJCEnp8eVjFcZFkIBQz7o=; b=PONRvXjhCsx/iRSbAsb+AgQrV1JrDyxHW1oOG69Y927zys45TruwM1OqGJFlGU4PXR neMVl4wj59KHiB1l7f3jZ5Qmpm39fKXA1dPBfgwb20nxnjvQXvzpA43RM1mxenhs6aOJ gGpHyG6VwBTSplQUVjYKq3vG8E3eaB9KZwsVomWLzDSPIaJP9UKDtvUKmvoCs1Wz+EkA RPv0feWc7mWCUcOHwteCkQ4do8pElkv4aJycat8b76Q3W1V1dFYjOo9GZi5jjvGdLqCb 51l/j+bllJXLZh/Llc3uHxcmvk7N33VTPg+8tSezsUduBfe2GYynaoKv2SV6NpdU3fOP euxg== X-Gm-Message-State: AD7BkJITt1SDClB3dCHQyYvq+CZVaWoQ1ZiQwReFjfIRuiZWRCato26HGu+G+EMOJOwCQNh0 X-Received: by 10.194.184.112 with SMTP id et16mr24932212wjc.75.1458470112842; Sun, 20 Mar 2016 03:35:12 -0700 (PDT) Received: from xps13.localnet (91.111.75.86.rev.sfr.net. [86.75.111.91]) by smtp.gmail.com with ESMTPSA id i5sm20089198wja.23.2016.03.20.03.35.12 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 20 Mar 2016 03:35:12 -0700 (PDT) From: Thomas Monjalon To: Jan Viktorin Cc: dev@dpdk.org, jerin.jacob@caviumnetworks.com, tomaszx.kulasek@intel.com, jianbo.liu@linaro.org Date: Sun, 20 Mar 2016 11:33:37 +0100 Message-ID: <3300542.bjkaoNcO2a@xps13> Organization: 6WIND User-Agent: KMail/4.14.10 (Linux/4.1.6-1-ARCH; KDE/4.14.11; x86_64; ; ) In-Reply-To: <20160320104655.45a5c863@jvn> References: <1458417485-29436-1-git-send-email-viktorin@rehivetech.com> <20160320104110.3c05f405@jvn> <20160320104655.45a5c863@jvn> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Subject: Re: [dpdk-dev] [PATCH v3 4/4] eal/arm: introduce CONFIG_RTE_ARCH_ARM_NEON_MEMCPY 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: Sun, 20 Mar 2016 10:35:13 -0000 2016-03-20 10:46, Jan Viktorin: > On Sun, 20 Mar 2016 10:41:10 +0100 > Jan Viktorin wrote: > > > On Sat, 19 Mar 2016 21:14:57 +0100 > > Thomas Monjalon wrote: > > > > > 2016-03-19 20:58, Jan Viktorin: > > > > The flag is used to enable memcpy optimizations in EAL. As it is not always > > > > the performance benefit, the flag allows to disable it. > > > > > > Ideally the default should be to choose the best optimization. > > > If it is not possible, it would help to have some comments explaining > > > how to choose wether enabling NEON memcpy or not. > > The related statistics are mentioned here: > > commit 04a2fde35daf5e9a271e72331a70b48b951d7568 > Author: Vlastimil Kosar > Date: Tue Nov 3 00:47:20 2015 +0100 > > eal/arm: add vector memcpy for ARMv7 > > It's quite difficult to easily summarize it, especially for so many > CPUs... If it is difficult for you, it will be impossible for the users of this config option. When someone will ask what is the best value for his CPU, what will you answer? At least, we can add a comment explaining that the performance is not always better, depending of the buffer size and the CPU.