From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.tuxdriver.com (charlotte.tuxdriver.com [70.61.120.58]) by dpdk.org (Postfix) with ESMTP id E7F804A6E for ; Mon, 17 Nov 2014 14:56:57 +0100 (CET) Received: from hmsreliant.think-freely.org ([2001:470:8:a08:7aac:c0ff:fec2:933b] helo=localhost) by smtp.tuxdriver.com with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.63) (envelope-from ) id 1XqMxB-0000VJ-P8; Mon, 17 Nov 2014 09:07:10 -0500 Date: Mon, 17 Nov 2014 09:06:52 -0500 From: Neil Horman To: "Ananyev, Konstantin" Message-ID: <20141117140652.GC17886@hmsreliant.think-freely.org> References: <1409724351-23786-1-git-send-email-e_zhumabekov@sts.kz> <1416160760-16087-4-git-send-email-e_zhumabekov@sts.kz> <2601191342CEEE43887BDE71AB977258213AE40F@IRSMSX105.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2601191342CEEE43887BDE71AB977258213AE40F@IRSMSX105.ger.corp.intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Score: -2.9 (--) X-Spam-Status: No Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH v2 3/4] 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: Mon, 17 Nov 2014 13:56:58 -0000 On Mon, Nov 17, 2014 at 12:34:04PM +0000, Ananyev, Konstantin wrote: > > Hi Yerden, > > > -----Original Message----- > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Yerden Zhumabekov > > Sent: Sunday, November 16, 2014 5:59 PM > > To: dev@dpdk.org > > Subject: [dpdk-dev] [PATCH v2 3/4] hash: add fallback to software CRC32 implementation > > > > Initially, SSE4.2 support is detected via CPUID instruction. > > > > Added rte_hash_crc_set_alg() function to detect and set CRC32 > > implementation if necessary. SSE4.2 is allowed by default. If it's > > not available, fall back to sw implementation. > > > > Signed-off-by: Yerden Zhumabekov > > --- > > lib/librte_hash/rte_hash_crc.h | 60 ++++++++++++++++++++++++++++++++++++++-- > > 1 file changed, 58 insertions(+), 2 deletions(-) > > > > diff --git a/lib/librte_hash/rte_hash_crc.h b/lib/librte_hash/rte_hash_crc.h > > index 74e2d92..178b162 100644 > > --- a/lib/librte_hash/rte_hash_crc.h > > +++ b/lib/librte_hash/rte_hash_crc.h > > @@ -45,7 +45,11 @@ extern "C" { > > #endif > > > > #include > > +#ifdef RTE_MACHINE_CPUFLAG_SSE4_2 > > #include > > +#endif > > +#include > > +#include > > > > /* Lookup table for software implementation of CRC32C */ > > static const uint32_t crc32c_table[256] = { > > @@ -152,8 +156,42 @@ crc32c_2words(uint64_t data, uint32_t init_val) > > return init_val; > > } > > > > +enum crc32_alg_t { > > + CRC32_SW = 0, > > + CRC32_SSE42, > > + CRC32_AUTODETECT > > +}; > > + > > +/* Default algorithm is left for autodetection, > > + * it is detected on first run of hash function > > + */ > > +static enum crc32_alg_t crc32_alg = CRC32_AUTODETECT; > > + > > +/** > > + * Allow or disallow use of SSE4.2 instrinsics for CRC32 hash > > + * hash calculation. > > + * > > + * @param flag > > + * unsigned integer flag > > + * - (CRC32_SW) Don't use SSE4.2 intrinsics > > + * - (CRC32_SSE42) Use SSE4.2 intrinsics if available, set by default > > + */ > > +static inline void > > +rte_hash_crc_set_alg(enum crc32_alg_t alg) > > +{ > > + int sse42_supp = rte_cpu_get_flag_enabled(RTE_CPUFLAG_SSE4_2); > > + enum crc32_alg_t alg_supp = sse42_supp ? CRC32_SSE42 : CRC32_SW; > > + > > + if (alg == CRC32_SSE42) > > + crc32_alg = alg_supp; > > + else > > + crc32_alg = CRC32_SW; > > +} > > + > > Wonder can we define that function with __attribute__((constructor))? > Then, I suppose we can remove CRC32_AUTODETECT, and remove: > if (unlikely(crc32_alg == CRC32_AUTODETECT)) > rte_hash_crc_set_alg(CRC32_SSE42); > from rte_hash_crc_*byte(). > That would make sense. Neil