From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by dpdk.space (Postfix) with ESMTP id 06891A046B for ; Tue, 25 Jun 2019 13:30:31 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 868B11BA9A; Tue, 25 Jun 2019 13:30:31 +0200 (CEST) Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by dpdk.org (Postfix) with ESMTP id 227DE1BA96 for ; Tue, 25 Jun 2019 13:30:29 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Jun 2019 04:30:29 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,415,1557212400"; d="scan'208";a="359913056" Received: from aburakov-mobl1.ger.corp.intel.com (HELO [10.237.220.101]) ([10.237.220.101]) by fmsmga005.fm.intel.com with ESMTP; 25 Jun 2019 04:30:27 -0700 To: Jerin Jacob Kollanukkaran , Vamsi Krishna Attunuru , "dev@dpdk.org" Cc: "ferruh.yigit@intel.com" , "olivier.matz@6wind.com" , "arybchenko@solarflare.com" References: <20190422061533.17538-1-kirankumark@marvell.com> <20190625035700.2953-1-vattunuru@marvell.com> <51e1b2c8-4290-c9b5-701f-5be55e763425@intel.com> From: "Burakov, Anatoly" Message-ID: <4906aad7-47a2-6707-cf69-417043c46c8c@intel.com> Date: Tue, 25 Jun 2019 12:30:26 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 25-Jun-19 12:15 PM, Jerin Jacob Kollanukkaran wrote: >> -----Original Message----- >> From: dev On Behalf Of Burakov, Anatoly >> Sent: Tuesday, June 25, 2019 3:30 PM >> To: Vamsi Krishna Attunuru ; dev@dpdk.org >> Cc: ferruh.yigit@intel.com; olivier.matz@6wind.com; >> arybchenko@solarflare.com >> Subject: Re: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI >> >> On 25-Jun-19 4:56 AM, vattunuru@marvell.com wrote: >>> From: Vamsi Attunuru >>> >>> ---- >>> V6 Changes: >>> * Added new mempool flag to ensure mbuf memory is not scattered across >>> page boundaries. >>> * Added KNI kernel module required PCI device information. >>> * Modified KNI example application to create mempool with new mempool >>> flag. >>> >> Others can chime in, but my 2 cents: this reduces the usefulness of KNI because >> it limits the kinds of mempools one can use them with, and makes it so that the >> code that works with every other PMD requires changes to work with KNI. > > # One option to make this flag as default only for packet mempool(not allow allocate on page boundary). > In real world the overhead will be very minimal considering Huge page size is 1G or 512M > # Enable this flag explicitly only IOVA = VA mode in library. Not need to expose to application > # I don’t think, there needs to be any PMD specific change to make KNI with IOVA = VA mode > # No preference on flags to be passed by application vs in library. But IMO this change would be > needed in mempool support KNI in IOVA = VA mode. > I would be OK to just make it default behavior to not cross page boundaries when allocating buffers. This would solve the problem for KNI and for any other use case that would rely on PA-contiguous buffers in face of IOVA as VA mode. We could also add a flag to explicitly allow page crossing without also making mbufs IOVA-non-contiguous, but i'm not sure if there are use cases that would benefit from this. > > >> >> -- >> Thanks, >> Anatoly -- Thanks, Anatoly