From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id AA4712935 for ; Tue, 4 Jul 2017 01:19:38 +0200 (CEST) Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Jul 2017 16:19:37 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,305,1496127600"; d="scan'208";a="104124764" Received: from irsmsx102.ger.corp.intel.com ([163.33.3.155]) by orsmga004.jf.intel.com with ESMTP; 03 Jul 2017 16:19:36 -0700 Received: from irsmsx108.ger.corp.intel.com ([169.254.11.133]) by IRSMSX102.ger.corp.intel.com ([169.254.2.211]) with mapi id 14.03.0319.002; Tue, 4 Jul 2017 00:19:35 +0100 From: "Dumitrescu, Cristian" To: Thomas Monjalon , Jianbo Liu CC: "dev@dpdk.org" , "jerin.jacob@caviumnetworks.com" , "ashwin.sekhar@caviumnetworks.com" Thread-Topic: [dpdk-dev] [PATCH] examples/ip_pipeline: use crc32 in hash functions for arm64 Thread-Index: AQHSz7Z23XUmksGd60GwJtdZdgtsO6JC0bUAgAAwm2A= Date: Mon, 3 Jul 2017 23:19:34 +0000 Message-ID: <3EB4FA525960D640B5BDFFD6A3D891267BA77E6C@IRSMSX108.ger.corp.intel.com> References: <1495098540-8303-1-git-send-email-jianbo.liu@linaro.org> <4804120.hkK0KHU9aJ@xps> In-Reply-To: <4804120.hkK0KHU9aJ@xps> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiYTNiMWY1NjMtNDdjYS00NjE3LThiZTEtYmJmMGI0NDZiZTQ0IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX0lDIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE2LjUuOS4zIiwiVHJ1c3RlZExhYmVsSGFzaCI6IlkzeEkwR2pFbVhLTTNWenFcL1ExWWFBVzhDOFFZXC9rRzdwTllidGYyRVFRND0ifQ== x-ctpclassification: CTP_IC dlp-product: dlpe-windows dlp-version: 10.0.102.7 dlp-reaction: no-action x-originating-ip: [163.33.239.180] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH] examples/ip_pipeline: use crc32 in hash functions for arm64 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: , X-List-Received-Date: Mon, 03 Jul 2017 23:19:39 -0000 > -----Original Message----- > From: Thomas Monjalon [mailto:thomas@monjalon.net] > Sent: Monday, July 3, 2017 10:12 PM > To: Jianbo Liu ; Dumitrescu, Cristian > > Cc: dev@dpdk.org; jerin.jacob@caviumnetworks.com; > ashwin.sekhar@caviumnetworks.com > Subject: Re: [dpdk-dev] [PATCH] examples/ip_pipeline: use crc32 in hash > functions for arm64 >=20 > 18/05/2017 11:09, Jianbo Liu: > > Implement the same hash functions with crc32 on arm platform. > > > > Signed-off-by: Jianbo Liu > > --- > > examples/ip_pipeline/pipeline/hash_func.h | 2 + > > examples/ip_pipeline/pipeline/hash_func_arm64.h | 245 > ++++++++++++++++++++++++ > > 2 files changed, 247 insertions(+) > > create mode 100644 examples/ip_pipeline/pipeline/hash_func_arm64.h >=20 > I don't understand why this code is in an example. > We have some CRC code in librte_hash, librte_net and ip_pipeline. > Cristian, Jianbo, > does it make sense to move these functions somewhere else? >=20 I think example apps are a great way to propose new hash functions. IMO we = should encourage the definition/exploration of new hash functions in our example apps. These functions are examples of how fast hash functions can be built using = special CPU instructions. They have much better performance than e.g. jhash, but their properties are= largely unknown, as no rigorous study on their properties (such as uniform distribution) has been = conducted. I have seen them providing good performance for the data set I have been using, but I have = no extensive data to support their maturity level. If somebody is willing to invest the effort in proving them, I would be mor= e than happy to see them moved to a library like librte_hash. Pablo as maintainer has the choice (I = think it is not the first time we discuss bout these hash funcs :) ) As mentioned in one of our deprecation notices, I am actively working (not = ready for 17.8 unfortunately) to add a key mask parameter to these functions, so more work on these hash = functions is likely to take place.