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 C9CFB595B for ; Wed, 19 Nov 2014 04:41:40 +0100 (CET) Received: from mgw.gov.kz (mx.ctsat.kz [178.89.4.95]) by mgw.gov.kz with ESMTP id sAJ3q1pr013398-sAJ3q1pt013398 (version=TLSv1.0 cipher=AES128-SHA bits=128 verify=NO); Wed, 19 Nov 2014 09:52:02 +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; Wed, 19 Nov 2014 09:51:50 +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; Wed, 19 Nov 2014 09:52:01 +0600 Message-ID: <546C13B6.9090904@sts.kz> Date: Wed, 19 Nov 2014 09:51:18 +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 , Bruce Richardson 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> <546B7E2D.7050705@sts.kz> <20141118174619.GE32375@hmsreliant.think-freely.org> <20141118175226.GC5840@bricha3-MOBL3> <20141118213624.GF32375@hmsreliant.think-freely.org> In-Reply-To: <20141118213624.GF32375@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 Cc: "dev@dpdk.org" 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: Wed, 19 Nov 2014 03:41:41 -0000 19.11.2014 3:36, Neil Horman =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > On Tue, Nov 18, 2014 at 05:52:27PM +0000, Bruce Richardson wrote: >> On Tue, Nov 18, 2014 at 12:46:19PM -0500, Neil Horman wrote: >>> On Tue, Nov 18, 2014 at 11:13:17PM +0600, Yerden Zhumabekov wrote: >>>> Everybody's up for the second option? :) >>>> >>> Crud, you're right, I didn't think about the header inclusion issue. = Is it >>> worth adding the jump to enable the dynamic hash selection? >>> Neil >> Maybe for cases where SSE4.2 is not currently available, i.e. for gene= ric builds. >> For builds where we have hardware support confirmed at compile time, j= ust use >> the function from the header file. >> Does that make sense? >> > I'm not certain of that, as I don't think anything can be 'confirmed' a= t compile > time. I.e. just because you have sse42 at compile time doesn't guarant= ee you > have it at run time with a DSO. If you have these as macros, you need = to enable > sse42 whereever you include the file so that the intrinsic works proper= ly. > > an alternate option would be to not use the intrinsic, and craft some e= xplicit > __asm__ statement that executes the right sse42 instructions. That way= the asm > is directly emitted, without requiring the -msse42 flag at all, and it = will just > work in all the files that call it. Thanks for the discussion. To summarize it with my suggestions for 'v5': 1) replace intrinsics with asm code and give up including nmmintrin.h; 2) detect arch (EM64T flag) on runtime because crc32 for 64-bit operand doesn't work on 32-bit x86; 3) separate function prototypes (leaving them in header) and bodies, add to SRCS in Makefile. --=20 Sincerely, Yerden Zhumabekov State Technical Service Astana, KZ