From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f65.google.com (mail-pl0-f65.google.com [209.85.160.65]) by dpdk.org (Postfix) with ESMTP id 7CDFF4F94 for ; Wed, 28 Feb 2018 16:15:30 +0100 (CET) Received: by mail-pl0-f65.google.com with SMTP id 61-v6so1678279plf.3 for ; Wed, 28 Feb 2018 07:15:30 -0800 (PST) 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=Rp/7L9wiUJqYnF4EwLI7EWrqZXgSE/6xH9Q0kSauQLg=; b=dCvyJIF932+2LCl1Rjkv5fEd4ZDTMtd9I6F61mFPApcUbJ5GMWLxFeWVgcvdQ/i5fY KLYGyIqWcVJxWw4+R3wwfyCPr9Y8sKLTXC5N/2nEs25stBL/Cupt2zWRv9cHjj/YMZg/ A65E0FiPZKnfGWePaqLnEfbMqfl4nDV9EgmalBmGmCApKrhCNYLtLbhgc9Ms/8sJ7ilE s1ZHUYSeuPyjX5ttzr35Ni/z7DuMg97pTRMFbtKsFCwpthhyyNqXVPZWv4TZDSn2PTOE itwaWH6OWpAN/p0ToaAJQ5RVPpzGT2oUyL9BzDhgiN9shz32ZMZtD2roTe9ryn3Y2cpX TGTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Rp/7L9wiUJqYnF4EwLI7EWrqZXgSE/6xH9Q0kSauQLg=; b=V2trD5m/Q2H2EIexUL0kK9JbVvQCr6FFDeZZYq2gQ8K/n59gXcfl04Sr4Ow97h6XNz VkYP4t6gu9XY2aLcl1H2L0MkJGFl1nBShrhMKAHWqrs4vGc9KeEnhIFy0O76rdj6rEql 76nNerNfmwY/WImbibYqEqLXhuQvAL1CpaisbI/D9MEmEvBZOYCmmjsiwhzWyi3DP/k4 kK5/R39C5C8+RjuECgRsLvMymPx5Po1oHWWEkNAm8p/msCs2RiE1yc6n7rTWOoxdae4x QhTk7McdU1iaMMpzFit90sxBV+pQRgmXj+G4+syYXdh2pLSXu2h7Qg2b29hkF5hCAkPa fYng== X-Gm-Message-State: APf1xPCtJHK8sGukMqzEPvKuyIX00cWUBmDpLRq/9e5gZTznlTtLTY4n dYstuuo5qn1oDplWct+zPNLYw2qjtSI= X-Google-Smtp-Source: AH8x227/4Bpi45jZa3qaoFJ+cYFKya+BmuTvqaaz9ZtDA0two8Yyh4OkCtnbF9DmV/J/LaN11dspYw== X-Received: by 2002:a17:902:74c3:: with SMTP id f3-v6mr18430509plt.444.1519830929581; Wed, 28 Feb 2018 07:15:29 -0800 (PST) Received: from xeon-e3 (204-195-71-95.wavecable.com. [204.195.71.95]) by smtp.gmail.com with ESMTPSA id a138sm4486372pfd.47.2018.02.28.07.15.29 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 28 Feb 2018 07:15:29 -0800 (PST) Date: Wed, 28 Feb 2018 07:15:20 -0800 From: Stephen Hemminger To: =?UTF-8?B?R2HDq3Rhbg==?= Rivet Cc: Yuliang Li , users@dpdk.org Message-ID: <20180228071520.3e9d090f@xeon-e3> In-Reply-To: <20180228092728.ezf2zic2vjfpzalq@bidouze.vm.6wind.com> References: <20180228092728.ezf2zic2vjfpzalq@bidouze.vm.6wind.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [dpdk-users] occasionally ~300us delay X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Feb 2018 15:15:30 -0000 On Wed, 28 Feb 2018 10:27:28 +0100 Ga=C3=ABtan Rivet wrote: > Hi, >=20 > On Wed, Feb 28, 2018 at 12:03:30AM -0500, Yuliang Li wrote: > > Also, such pause happens regularly--every 0.5s. > >=20 > > On Wed, Feb 28, 2018 at 12:01 AM, Yuliang Li wrot= e: > > =20 > > > Hi all, > > > > > > I am using dpdk to generate packets. Specifically, I have a list of > > > , meaning I want to send Pi at Ti. I wait for Ti = by while > > > (rte_get_tsc_cycles() > > 300us of sending packets, i.e., the sending time of some Pi is around > > > Ti+300us. It looks like the program just pauses by 300us, and then re= sumes. > > > Does anyone know why? > > > > > > Thanks, =20 > > =20 >=20 > I would reduce entropy and gather more data. >=20 > You can isolate your process (i.e. numactl), if possible not on core 0, d= isable > hyper-threading, disable CPU frequency scaling. >=20 > Then, running your app: >=20 > # grep ctxt_sw /proc/$(pidof your-dpdk-app)/status >=20 > If you have context switches, then you have other tasks throwing off your= measures. > The rte-intr-thread is notorious for having bad affinities and triggering= context > switches, and can be used for alarms (thus, possible regular occurence). >=20 > Regards, Sounds like SMI