From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f43.google.com (mail-wg0-f43.google.com [74.125.82.43]) by dpdk.org (Postfix) with ESMTP id 508DF5934 for ; Fri, 29 Nov 2013 19:19:59 +0100 (CET) Received: by mail-wg0-f43.google.com with SMTP id k14so6937400wgh.34 for ; Fri, 29 Nov 2013 10:21:00 -0800 (PST) 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:content-type; bh=xqaOgPNPJC5ddyjYap2/Ghri9d6J2BT0Jh00qjmy+HU=; b=MUCg+tCqOoa+UVOybiBDipIXcPviuoSRlycp6kdIoB3sfOK1qD8y+aZsSjxTCnESny MRlVSknLcLeIc/IRiznumWeNOHL3fbg+tPSGy+ypz4Y5N4WGnERrspYAx85wTsBbuZRK OjD4sFFuaD4m0YMnR1D/sQP5qy8oPIPPUWWs6zOfMzlXKvot1BI/bWqQHW6PERedxCb3 kUUviuDFOLSD51rmMknfFREMpprwRQQPuc3rPwL0hTzSBqKMGGg+0iCSfIgHhPRNz2IX AwN7SSiVtTnSqC+18opXbq9wfUiUK6+lE53EzfC/BMN0q/tCCjZ5f/MerKMUtiujyPEz +WeA== X-Gm-Message-State: ALoCoQny0mKub58Te5wGOP5SuZCmtFkd5F0C51HFBJl5ofOMR2PPKh6UrUcDP8myHIH8dxMDwRir X-Received: by 10.180.208.49 with SMTP id mb17mr7974256wic.64.1385749259868; Fri, 29 Nov 2013 10:20:59 -0800 (PST) Received: from x220.localnet (14.21.90.92.rev.sfr.net. [92.90.21.14]) by mx.google.com with ESMTPSA id hv5sm93942689wib.2.2013.11.29.10.20.57 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 29 Nov 2013 10:20:58 -0800 (PST) From: Thomas Monjalon To: Dmitry Vyal Date: Fri, 29 Nov 2013 10:20:58 -0800 (PST) Message-ID: <4967601.BLy1PQ6cQ3@x220> Organization: 6WIND User-Agent: KMail/4.11.2 (Linux/3.11.4-1-ARCH; KDE/4.11.2; x86_64; ; ) In-Reply-To: <3439195.NJQbpGS54N@x220> References: <528F4E41.2000405@gmail.com> <52987236.3020707@gmail.com> <3439195.NJQbpGS54N@x220> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] Sporadic errors while initializing NICs in example applications, dpdk-1.5.0r1 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: Fri, 29 Nov 2013 18:19:59 -0000 Thomas29/11/2013 13:25, Monjalon : > 29/11/2013 14:53, Dmitry Vyal : > > On 11/28/2013 03:01 PM, Richardson, Bruce wrote: > > > [BR] Frequency changes should not affect timers for modern Intel CPUs. > > > > The error frequency greatly reduces if I patch > > loop limit as I described earlier or if I call rte_power_init and > > rte_power_freq_max as Thomas suggested. > > > > But the only way to get rid of them completely is to set performance > > governor. > > Please check that your hardware do not support invariant TSC. > It would explain why you need to fix frequency. > > I attach a simple code to test CPU feature "Invariant TSC". Note that this feature is called constant_tsc in /proc/cpuinfo: grep --color -m1 constant_tsc /proc/cpuinfo It is checked by check_tsc_flags() at DPDK initialization and should print a warning if missing: http://dpdk.org/browse/dpdk/commit/?id=e7c8996e13b9abb706ea0de53271346f4f86ca03 -- Thomas