From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 08AF03B5 for ; Tue, 7 Oct 2014 06:10:30 +0200 (CEST) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP; 06 Oct 2014 21:17:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,667,1406617200"; d="scan'208";a="601567369" Received: from fmsmsx104.amr.corp.intel.com ([10.18.124.202]) by fmsmga001.fm.intel.com with ESMTP; 06 Oct 2014 21:17:40 -0700 Received: from fmsmsx152.amr.corp.intel.com (10.18.125.5) by fmsmsx104.amr.corp.intel.com (10.18.124.202) with Microsoft SMTP Server (TLS) id 14.3.195.1; Mon, 6 Oct 2014 21:17:40 -0700 Received: from bgsmsx103.gar.corp.intel.com (10.223.4.130) by FMSMSX152.amr.corp.intel.com (10.18.125.5) with Microsoft SMTP Server (TLS) id 14.3.195.1; Mon, 6 Oct 2014 21:17:40 -0700 Received: from bgsmsx102.gar.corp.intel.com ([169.254.2.43]) by BGSMSX103.gar.corp.intel.com ([169.254.4.94]) with mapi id 14.03.0195.001; Tue, 7 Oct 2014 09:47:37 +0530 From: "Ramia, Kannan Babu" To: Ravi Kumar Iyer , "dev@dpdk.org" Thread-Topic: Queries related to Hyperthreading Thread-Index: AQHP4d7bTwtgqh2uckSVy5a9owetGZwkBT0g Date: Tue, 7 Oct 2014 04:17:37 +0000 Message-ID: <682698A055A0F44AA47192B20141149711B3E893@BGSMSX102.gar.corp.intel.com> References: <5E927AAF66A09F419D11E0CDC6794A367EF8AD85AB@GUREXMB01.ASIAN.AD.ARICENT.COM> In-Reply-To: <5E927AAF66A09F419D11E0CDC6794A367EF8AD85AB@GUREXMB01.ASIAN.AD.ARICENT.COM> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.223.10.10] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] Queries related to Hyperthreading 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: Tue, 07 Oct 2014 04:10:31 -0000 Hi Ravi The Intel HT actually has its own resources except few places like executio= n units and other resources in the pipeline, hence there are many factors p= lay here for the performance of the application with and without HT feature= . In simple words, even when you turned on the HT, and use only one of the = HT, then the performance will be more or less be similar to the core with H= T turned off. Also assume that if you are running same piece of code in bot= h the HTs, but it doesn't have lots have contention on the common resource = (you can figure out this using vTune profiling), then there will be very ma= rginal performance difference between HT turned ON Vs OFF. Regards Kannan Babu -----Original Message----- From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Ravi Kumar Iyer Sent: Tuesday, October 7, 2014 8:59 AM To: dev@dpdk.org Subject: [dpdk-dev] Queries related to Hyperthreading hello Intel Gurus, I have some queries related to intel HT technology. I am running an intel d= pdk application and trying to benchmark as well as optimize the same. As o= f now it is a single threaded application and would like to keep it like th= at for now. I am running it on an intel sandy bridge arch processor with HT= on. Now to increase the performance I have disabled HT, but am still getti= ng the same performance[ just a marginal improvement]. Now as per our under= standing so far wrt HT, two Hardware threads share the same physical core. = Now if we switch off HT[from bios] shouldn't just one hardware Thread get h= old of the complete CPU core. The application is heavily compute oriented = and as such minimal memory access or any IO operations. Appreciate any insi= ght on this. thanks ravi "DISCLAIMER: This message is proprietary to Aricent and is intended solely = for the use of the individual to whom it is addressed. It may contain privi= leged or confidential information and should not be circulated or used for = any purpose other than for what it is intended. If you have received this m= essage in error, please notify the originator immediately. If you are not t= he intended recipient, you are notified that you are strictly prohibited fr= om using, copying, altering, or disclosing the contents of this message. Ar= icent accepts no responsibility for loss or damage arising from the use of = the information transmitted by this email including damage from virus."