From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f176.google.com (mail-wi0-f176.google.com [209.85.212.176]) by dpdk.org (Postfix) with ESMTP id 4513A5A15 for ; Thu, 22 Jan 2015 10:06:20 +0100 (CET) Received: by mail-wi0-f176.google.com with SMTP id em10so22531256wid.3 for ; Thu, 22 Jan 2015 01:06:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=9dIDiVltPhGUb1JcfBixBH5vdbffNvoyxzfnUVw4C+0=; b=TW8KCeT9e7zF0yEn9fqxAJplRVNwGI/wQI7g7+jidLetSSPO0X8vNzImoEU/A0TuQN cqjBL5tuKZx10lGvueNqZxxzIksFetT5IkU19zongKhPMYAyCwziyOED1sBDKIeSXojc h6TSUqFAVqJI5ie6feSF1wHu/x6Fqhxcc6VuaGxUmRSguyDx7K0xmL1TFhwgDUWw/dLv lAlEZXQsJAzi/LxEnVX0L4xDR738mU403abPkYndW4fzbg9gAJ1F1fUXA3WRmrep1m4o DqeSlJ2SddygHkr1Wmbc87zYBaS7n9ez06Y3EJdOyKPjaJx2cbOV0UTpDul1NE4F+HFU gSAw== MIME-Version: 1.0 X-Received: by 10.181.13.206 with SMTP id fa14mr17657357wid.57.1421917580094; Thu, 22 Jan 2015 01:06:20 -0800 (PST) Sender: lukego@gmail.com Received: by 10.27.75.203 with HTTP; Thu, 22 Jan 2015 01:06:19 -0800 (PST) In-Reply-To: <53D2253B-DE20-486E-ADF0-DA02AAB1EF35@netgate.com> References: <20150119130221.GB21790@hmsreliant.think-freely.org> <20150120151118.GD18449@hmsreliant.think-freely.org> <20150120161453.GA5316@bricha3-MOBL3> <54BF9D59.7070104@bisdn.de> <20150121130234.GB10756@bricha3-MOBL3> <54BFA7D5.7020106@bisdn.de> <20150121132620.GC10756@bricha3-MOBL3> <20150121114947.0753ae87@urahara> <20150121205404.GB32617@hmsreliant.think-freely.org> <53D2253B-DE20-486E-ADF0-DA02AAB1EF35@netgate.com> Date: Thu, 22 Jan 2015 10:06:19 +0100 X-Google-Sender-Auth: StsRWtjBuiZyx4Av82sk178TQQw Message-ID: From: Luke Gorrie To: Jim Thompson Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH 0/4] DPDK memcpy optimization 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: Thu, 22 Jan 2015 09:06:20 -0000 Howdy! This memcpy discussion is absolutely fascinating. Glad to be a fly on the wall! On 21 January 2015 at 22:25, Jim Thompson wrote: > > The differences with DPDK are that a) entire cores (including the AVX/SSE > units and even AES-NI (FPU) are dedicated to DPDK, and b) DPDK is a libra= ry, > and the resulting networking applications are exactly that, applications. > The "operating system=E2=80=9D is now a control plane. > > Here is another thought: when is it time to start thinking of packet copy as a cheap unit-time operation? Packets are shrinking exponentially when measured in: - Cache lines - Cache load/store operations needed to copy - Number of vector move instructions needed to copy because those units are all based on exponentially growing quantities, while the byte size of packets stays the same for many applications. So when is it time to stop caring? (Are we already there, even, for certain conditions? How about Haswell CPU, data already exclusively in our L1 cache, start and end both known to be cache-line-aligned?) Cheers, -Luke (eagerly awaiting arrival of Haswell server...)