From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mgw.gov.kz (mgw.gov.kz [89.218.88.242]) by dpdk.org (Postfix) with ESMTP id DCC8E7EB0 for ; Tue, 18 Nov 2014 18:03:40 +0100 (CET) Received: from mgw.gov.kz (mx.ctsat.kz [178.89.4.95]) by mgw.gov.kz with ESMTP id sAIHE0CK022404-sAIHE0CM022404 (version=TLSv1.0 cipher=AES128-SHA bits=128 verify=NO); Tue, 18 Nov 2014 23:14:00 +0600 Received: from EXCASHUB1.rgp.local (192.168.40.51) by EdgeForefront.rgp.local (192.168.40.59) with Microsoft SMTP Server (TLS) id 14.2.247.3; Tue, 18 Nov 2014 23:13:49 +0600 Received: from [192.168.35.15] (192.168.35.15) by excashub1.rgp.local (192.168.40.48) with Microsoft SMTP Server (TLS) id 14.2.247.3; Tue, 18 Nov 2014 23:14:00 +0600 Message-ID: <546B7E2D.7050705@sts.kz> Date: Tue, 18 Nov 2014 23:13:17 +0600 From: Yerden Zhumabekov User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Neil Horman , "Richardson, Bruce" , "dev@dpdk.org" References: <1409724351-23786-1-git-send-email-e_zhumabekov@sts.kz> <20141118144138.GB32375@hmsreliant.think-freely.org> <546B607B.9030808@sts.kz> <20141118160005.GC32375@hmsreliant.think-freely.org> In-Reply-To: <20141118160005.GC32375@hmsreliant.think-freely.org> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Originating-IP: [192.168.35.15] X-FEAS-SYSTEM-WL: e_zhumabekov@sts.kz Subject: Re: [dpdk-dev] [PATCH v4 3/5] hash: add fallback to software CRC32 implementation 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, 18 Nov 2014 17:03:41 -0000 18.11.2014 22:00, Neil Horman =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > On Tue, Nov 18, 2014 at 09:06:35PM +0600, Yerden Zhumabekov wrote: >> 18.11.2014 20:41, Neil Horman =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>> On Tue, Nov 18, 2014 at 08:03:40PM +0600, Yerden Zhumabekov wrote: >>>> /** >>>> * Use single crc32 instruction to perform a hash on a 4 byte value= =2E >>>> + * Fall back to software crc32 implementation in case SSE4.2 is >>>> + * not supported >>>> * >>>> * @param data >>>> * Data to perform hash on. >>>> @@ -376,11 +413,18 @@ crc32c_2words(uint64_t data, uint32_t init_val= ) >>>> static inline uint32_t >>>> rte_hash_crc_4byte(uint32_t data, uint32_t init_val) >>>> { >>>> - return _mm_crc32_u32(init_val, data); >>>> +#ifdef RTE_MACHINE_CPUFLAG_SSE4_2 >>>> + if (likely(crc32_alg =3D=3D CRC32_SSE42)) >>>> + return _mm_crc32_u32(init_val, data); >>>> +#endif >>> you don't really need these ifdefs here anymore given that you have a= >>> constructor to do the algorithm selection. In fact you need to remov= e them, in >>> the event you build on a system that doesn't support SSE42, but run o= n a system >>> that does. >> Originally, I thought so as well. I wrote the code without these ifdef= s, >> but it didn't compile on my machine which doesn't support SSE4.2. Erro= r >> was triggered by nmmintrin.h which has a check for respective GCC >> extension. So I think these ifdefs are indeed required. >> > You need to edit the makefile so that the compiler gets passed the opti= on > -msse42. That way it will know to emit sse42 instructions. It will als= o allow > you to remove the ifdef from the include file In this case, I guess there are two options: 1) modify all makefiles which use librte_hash 2) move all function bodies from rte_hash_crc.h to separate module, leaving prototype definitions there only. Everybody's up for the second option? :) --=20 Sincerely, Yerden Zhumabekov State Technical Service Astana, KZ