From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yerden Zhumabekov Subject: Re: [PATCH v5 4/7] hash: add rte_hash_crc_8byte function Date: Fri, 21 Nov 2014 17:26:18 +0600 Message-ID: <546F215A.8060608@sts.kz> References: <1409724351-23786-1-git-send-email-e_zhumabekov@sts.kz> <5bc163e39a2e8176f7e0b424c70bb051d2f5a0a8.1416459284.git.e_zhumabekov@sts.kz> <20141121112242.GA20661@hmsreliant.think-freely.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Cc: dev-VfR2kkLFssw@public.gmane.org To: Neil Horman Return-path: In-Reply-To: <20141121112242.GA20661-B26myB8xz7F8NnZeBjwnZQMhkBWG/bsMQH7oEaQurus@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" 21.11.2014 17:22, Neil Horman =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > On Thu, Nov 20, 2014 at 11:16:34AM +0600, Yerden Zhumabekov wrote: >> SSE4.2 provides CRC32 intrinsic with 8-byte operand. >> >> Signed-off-by: Yerden Zhumabekov >> --- >> lib/librte_hash/rte_hash_crc.h | 16 ++++++++++++++++ >> 1 file changed, 16 insertions(+) >> >> diff --git a/lib/librte_hash/rte_hash_crc.h b/lib/librte_hash/rte_hash= _crc.h >> index cd28833..2c8ec99 100644 >> --- a/lib/librte_hash/rte_hash_crc.h >> +++ b/lib/librte_hash/rte_hash_crc.h >> @@ -413,6 +413,22 @@ rte_hash_crc_4byte(uint32_t data, uint32_t init_v= al) >> } >> =20 >> /** >> + * Use single crc32 instruction to perform a hash on a 8 byte value. >> + * >> + * @param data >> + * Data to perform hash on. >> + * @param init_val >> + * Value to initialise hash generator. >> + * @return >> + * 32bit calculated hash value. >> + */ >> +static inline uint32_t >> +rte_hash_crc_8byte(uint64_t data, uint32_t init_val) >> +{ >> + return crc32c_sse42_u64(data, init_val); >> +} >> + >> +/** >> * Use crc32 instruction to perform a hash. >> * >> * @param data >> --=20 >> 1.7.9.5 >> >> > I'm sorry, it may be early here, so I may be missing something. The ass= embly > implementations look great, but if a user calls rte_hash_crc_8byte on a= system > that doesn't support ss342, how do they wind up getting into the softwa= re crc > implementation given what you have above? > Neil After applying patch 4 out of 7 - there's no fall back. Fall back to SW crc32 algorithm is in patch 5/7. Moreover, after patch 5/7 there's a detection if the platform supports 64-bit, otherwise 64-bit operand support is mimicked using two 32-bit function calls. --=20 Sincerely, Yerden Zhumabekov State Technical Service Astana, KZ