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 CF479592C for ; Tue, 18 Nov 2014 05:46:49 +0100 (CET) Received: from mgw.gov.kz (mx.ctsat.kz [178.89.4.95]) by mgw.gov.kz with ESMTP id sAI4v7uS011781-sAI4v7uU011781 (version=TLSv1.0 cipher=AES128-SHA bits=128 verify=NO); Tue, 18 Nov 2014 10:57:08 +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 10:56:56 +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 10:57:10 +0600 Message-ID: <546AD178.9070109@sts.kz> Date: Tue, 18 Nov 2014 10:56:24 +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: References: <1416160760-16087-1-git-send-email-e_zhumabekov@sts.kz> In-Reply-To: Content-Type: text/plain; charset="windows-1251" Content-Transfer-Encoding: 8bit X-Originating-IP: [192.168.35.15] X-FEAS-SYSTEM-WL: e_zhumabekov@sts.kz Subject: Re: [dpdk-dev] [PATCH v3 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 04:46:50 -0000 Sorry, maybe I made a mistake here. Accoring to lib/librte_eal/common/eal_common_cpuflags.c code, it seemed to me that constructor attribute is not supported by intel compiler. So in that case here I decided to leave the code for autodetection. Am I correct? 18.11.2014 9:21, Yerden Zhumabekov пишет: > 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. > > Depending on compiler attributes support, best available algorithm > may be detected upon application startup. > > Signed-off-by: Yerden Zhumabekov > --- > lib/librte_hash/rte_hash_crc.h | 64 ++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 62 insertions(+), 2 deletions(-) > > diff --git a/lib/librte_hash/rte_hash_crc.h b/lib/librte_hash/rte_hash_crc.h > index 15f687a..c1b75e8 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 tables for software implementation of CRC32C */ > static uint32_t crc32c_tables[8][256] = {{ > @@ -363,8 +367,44 @@ crc32c_2words(uint64_t data, uint32_t init_val) > return crc; > } > > +enum crc32_alg_t { > + CRC32_SW = 0, > + CRC32_SSE42, > + CRC32_AUTODETECT > +}; > + > +static enum crc32_alg_t crc32_alg = CRC32_AUTODETECT; > + > +/** > + * Allow or disallow use of SSE4.2 instrinsics for CRC32 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; > + crc32_alg = (alg == CRC32_SSE42) ? alg_supp : CRC32_SW; > +} > + > +/* Best available algorithm is detected via CPUID instruction */ > +#ifndef __INTEL_COMPILER > +static inline void __attribute__((constructor)) > +rte_hash_crc_try_sse42(void) > +{ > + rte_hash_crc_set_alg(CRC32_SSE42); > +} > +#endif > + > /** > * Use single crc32 instruction to perform a hash on a 4 byte value. > + * Fall back to software crc32 implementation in case SSE4.2 is > + * not supported > * > * @param data > * Data to perform hash on. > @@ -376,11 +416,22 @@ 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 __INTEL_COMPILER > + if (unlikely(crc32_alg == CRC32_AUTODETECT)) > + rte_hash_crc_set_alg(CRC32_SSE42); > +#endif > +#ifdef RTE_MACHINE_CPUFLAG_SSE4_2 > + if (likely(crc32_alg == CRC32_SSE42)) > + return _mm_crc32_u32(init_val, data); > +#endif > + > + return crc32c_1word(data, init_val); > } > > /** > * Use single crc32 instruction to perform a hash on a 8 byte value. > + * Fall back to software crc32 implementation in case SSE4.2 is > + * not supported > * > * @param data > * Data to perform hash on. > @@ -392,7 +443,16 @@ rte_hash_crc_4byte(uint32_t data, uint32_t init_val) > static inline uint32_t > rte_hash_crc_8byte(uint64_t data, uint32_t init_val) > { > - return _mm_crc32_u64(init_val, data); > +#ifdef __INTEL_COMPILER > + if (unlikely(crc32_alg == CRC32_AUTODETECT)) > + rte_hash_crc_set_alg(CRC32_SSE42); > +#endif > +#ifdef RTE_MACHINE_CPUFLAG_SSE4_2 > + if (likely(crc32_alg == CRC32_SSE42)) > + return _mm_crc32_u64(init_val, data); > +#endif > + > + return crc32c_2words(data, init_val); > } > > /** -- Sincerely, Yerden Zhumabekov State Technical Service Astana, KZ