From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f172.google.com (mail-pf0-f172.google.com [209.85.192.172]) by dpdk.org (Postfix) with ESMTP id F13DC37AF for ; Wed, 13 Apr 2016 20:10:02 +0200 (CEST) Received: by mail-pf0-f172.google.com with SMTP id c20so37356954pfc.1 for ; Wed, 13 Apr 2016 11:10:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=cbGm1+ZcR4PiaTwysZScK+8knwAQN9fp3C+XXvRAsaA=; b=sagEStQqVRVmzb2iWOSFxOLHozuHs+tIIQA4k/yXHcVQnNXdLC477iwF4tFpe6iMTC 9/5X0VNbdsR5al1w6W9wvWUxL+sj4u+sM2z6RX3G63mj5SNBaVa8NV9oR9nKwAChCaQx 7OpYvtNqez6ffzhNwbRx1s71d7mUalHSPNNR9nAOZmu8CvVPP2C2F+GTQVqiHspc1i08 G+DooKEVCsiWt0qxAr+4/TN4wRikYMqFkMI96TqlUTRAcKHISDdwcdMhw4W8cPGckhf9 ZKNwbgf9J9+m1yXuc35dva5LZaJt3SVFOTm5ADa2kstRDDR7bplJ4+f4P8FNh3SnLarW 9FYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=cbGm1+ZcR4PiaTwysZScK+8knwAQN9fp3C+XXvRAsaA=; b=bHFL9VUhUXGvwz3NlGPhM7Cv3Yedyln/shhna0lc0h0G3ZUfpe6UcBUffszMPHdJxL dYhnm9Wkqfm8veIXlfiUJpV+NZHKkNV2+Quy810hSb1zAUzClNCHFQ1tNjvw/EC67Wip 85ntR6K5qob4Tp3jJxZCdZwLAAx1pnHvMNbLLJk913JTvp32lTBvBWt7xRHFamql5IW2 VbCoAf3mWWZPQldJS4GOGhGdF8NA8ismX6TP5nPsOK/aumXPpspOdjEFnqHsWGW3PHKR olXB2XVGNK6T7+80VSeZpWaXmAZwV/R0tQFwmU3bXimdN2eYbyE5lwFIGZmOv9gQ3V0z MwBA== X-Gm-Message-State: AOPr4FUbOyBMozJmG4Q9be0CFfQ1uc+uZsnBK07+48imAIfIqIp+jWo/UercCP6xI3bMdA== X-Received: by 10.98.86.157 with SMTP id h29mr14765489pfj.105.1460571002298; Wed, 13 Apr 2016 11:10:02 -0700 (PDT) Received: from xeon-e3 (static-50-53-71-109.bvtn.or.frontiernet.net. [50.53.71.109]) by smtp.gmail.com with ESMTPSA id 17sm52561770pfp.96.2016.04.13.11.10.01 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 13 Apr 2016 11:10:01 -0700 (PDT) Date: Wed, 13 Apr 2016 11:10:13 -0700 From: Stephen Hemminger To: Cliff Burdick Cc: users Message-ID: <20160413111013.2d56cb28@xeon-e3> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-users] Coremask X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Apr 2016 18:10:03 -0000 On Wed, 13 Apr 2016 09:42:29 -0700 Cliff Burdick wrote: > I don't see the answer to this in the documentation, so I'll try here. Why > function does the coremask that's required in rte_eal_init() actually do > other than tell the API what cores you're using? In other words, can't I > just set the core mask to all of the cores in my system, and selectively > use the ones I want? Is there a downside to that? What if the particular > thread running on an lcore isn't doing any DPDK functions? The coremask is used to determine which CPU's are setup and a per-cpu thread is started by the launch operation. You can tell EAL about as many CPU's as you want, either all or even just one. If you use all CPU's, then in the launch it is possible to have the thread function of unneeded CPU's return and go back to the launch idle loop.