From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f169.google.com (mail-wi0-f169.google.com [209.85.212.169]) by dpdk.org (Postfix) with ESMTP id 56756C51A for ; Mon, 29 Jun 2015 01:23:51 +0200 (CEST) Received: by wicnd19 with SMTP id nd19so56900616wic.1 for ; Sun, 28 Jun 2015 16:23:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=VnAnx0A3fRkjfLo/A9be6dBj8V7RgvheRDsXAneDTeg=; b=ALSroYrq1QJQ4QAOeDBNcnA7QxOSKenuPBoo05GSMa0EpxkmIOcZNJodEwmcyOs6g5 nvpSAeaFx+AK2CvVRol0X1FHTbT1o7/R3+2UwgPiP9Cm7+rZE1wwPKFC6Jbqi6sOGH56 B7WzEa4mqY1IvlJZTiGfxmxjdx+ImPKKWrw19xjW/oc9KOTEo6pM4ouopTI5sb3/Idkx BmPOwOP56Qk99gBHt6hmYME6ZxCJg0mFB58GLCWPbRIgTPVvFCFkFvPpZEi5mlHReEk+ I4GL4/PtcD9byMsUTRPldhi17VI6vYIXapzBx46m86U2hcm5Y7nyIEXEe97LNZf46Pj2 zDWw== MIME-Version: 1.0 X-Received: by 10.180.9.111 with SMTP id y15mr16444868wia.18.1435533831162; Sun, 28 Jun 2015 16:23:51 -0700 (PDT) Received: by 10.28.173.196 with HTTP; Sun, 28 Jun 2015 16:23:51 -0700 (PDT) In-Reply-To: References: Date: Mon, 29 Jun 2015 08:23:51 +0900 Message-ID: From: Keunhong Lee To: Abhishek Verma Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] Number of memory channels per processor socket? 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, 28 Jun 2015 23:23:51 -0000 See your motherboard spec. For example, I'm using Intel 5930K with ASUS X99 Delux Motherboard (x99 chipset). This site https://www.asus.com/us/Motherboards/X99DELUXE/specifications/ tells that "Quad Channel Memory Architecture " which means that "-n 4" is the correct configuration for me. To fully use quad channel memory, I have to use 4 separated DRAM, installed on different memory slots of my motherboard. -n option optimizes memory bank access pattern for datastructures. Since most motherboards support dual or quad memory channel, -n 4 will work for most systems. (Only few motherboards support tri-channel memory) I hope that this information is useful to you. Keunhong. 2015-06-28 18:54 GMT+09:00 Abhishek Verma : > Hi, > > I am new to DPDK and i tried searching the archives in case this had been > discussed but couldnt find any references and hence this email: > > What is the significance of " -n NUM: Number of memory channels per > processor socket" which is passed as an EAL option? I have a virtual > machine (VM) spawned using VirtualBox and i am trying to use DPDK to get > faster access to packets there. I did lscpu, but that didnt give me > anything interesting that i could use here: > > abhishekV@VirtualBox:~/dpdk/dpdk-2.0.0/x86_64-native-linuxapp-gcc/app$ > sudo > lscpu > [sudo] password for abhishekV: > > Architecture: x86_64 > CPU op-mode(s): 32-bit, 64-bit > Byte Order: Little Endian > CPU(s): 2 > On-line CPU(s) list: 0,1 > Thread(s) per core: 1 > Core(s) per socket: 2 > Socket(s): 1 > NUMA node(s): 1 > Vendor ID: GenuineIntel > CPU family: 6 > Model: 58 > Stepping: 9 > CPU MHz: 2594.017 > BogoMIPS: 5188.03 > L1d cache: 32K > L1d cache: 32K > L2d cache: 6144K > NUMA node0 CPU(s): 0,1 > abhishekV@VirtualBox:~/dpdk/dpdk-2.0.0/x86_64-native-linuxapp-gcc/app$ > > I understand that i have two cores and hence should use -c 1 (since i have > cores 0 and 1). However, i dont understand what to give as the "-n" option. > Is it always 4? > > Thanks, Abhishek >