From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 2339137A6 for ; Wed, 10 Feb 2016 13:16:27 +0100 (CET) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga103.fm.intel.com with ESMTP; 10 Feb 2016 04:16:27 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,425,1449561600"; d="scan'208";a="912262565" Received: from irsmsx109.ger.corp.intel.com ([163.33.3.23]) by fmsmga002.fm.intel.com with ESMTP; 10 Feb 2016 04:16:25 -0800 Received: from irsmsx108.ger.corp.intel.com ([169.254.11.102]) by IRSMSX109.ger.corp.intel.com ([169.254.13.100]) with mapi id 14.03.0248.002; Wed, 10 Feb 2016 12:16:24 +0000 From: "De Lara Guarch, Pablo" To: Didier Pallard , "dev@dpdk.org" , "Richardson, Bruce" Thread-Topic: [PATCH v2] hash: fix CRC32c computation Thread-Index: AQHRYx0xr+NDnmu4XkWPS619OJt0n58lD1vA Date: Wed, 10 Feb 2016 12:16:24 +0000 Message-ID: References: <1450776898-8951-1-git-send-email-didier.pallard@6wind.com> <1455010467-4991-1-git-send-email-didier.pallard@6wind.com> In-Reply-To: <1455010467-4991-1-git-send-email-didier.pallard@6wind.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiN2U3NmU0YzQtZDQ3MC00YzYyLWFlNzAtODhlOWZiNGQ3NDU4IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX0lDIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE1LjkuNi42IiwiVHJ1c3RlZExhYmVsSGFzaCI6Ik1uU204SzRHNlRKSm1iZlVyMThrXC9iVXNPNnhsZnBBSVFmdkRwTkx2bUdRPSJ9 x-ctpclassification: CTP_IC x-originating-ip: [163.33.239.181] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH v2] hash: fix CRC32c computation 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, 10 Feb 2016 12:16:28 -0000 Hi Didier, > -----Original Message----- > From: Didier Pallard [mailto:didier.pallard@6wind.com] > Sent: Tuesday, February 09, 2016 9:34 AM > To: dev@dpdk.org; Richardson, Bruce; De Lara Guarch, Pablo > Cc: jean-mickael.guerin@6wind.com; thomas.monjalon@6wind.com > Subject: [PATCH v2] hash: fix CRC32c computation >=20 > As demonstrated by the following code, CRC32c computation is not valid > when buffer length is not a multiple of 4 bytes: > (Output obtained by code below) >=20 > CRC of 1 NULL bytes expected: 0x527d5351 > soft: 527d5351 > rte accelerated: 48674bc7 > rte soft: 48674bc7 > CRC of 2 NULL bytes expected: 0xf16177d2 > soft: f16177d2 > rte accelerated: 48674bc7 > rte soft: 48674bc7 > CRC of 2x1 NULL bytes expected: 0xf16177d2 > soft: f16177d2 > rte accelerated: 8c28b28a > rte soft: 8c28b28a > CRC of 3 NULL bytes expected: 0x6064a37a > soft: 6064a37a > rte accelerated: 48674bc7 > rte soft: 48674bc7 > CRC of 4 NULL bytes expected: 0x48674bc7 > soft: 48674bc7 > rte accelerated: 48674bc7 > rte soft: 48674bc7 >=20 > Values returned by rte_hash_crc functions does not match the one > computed by a trivial crc32c implementation. >=20 > ARM code is not tested. >=20 > code showing the problem: >=20 > uint8_t null_test[32] =3D {0}; >=20 > static uint32_t crc32c_trivial(uint8_t *buffer, uint32_t length, uint32_t= crc) > { > uint32_t i, j; > for (i =3D 0; i < length; ++i) > { > crc =3D crc ^ buffer[i]; > for (j =3D 0; j < 8; j++) > crc =3D (crc >> 1) ^ 0x80000000 ^ ((~crc & 1) * 0x82f63b78); > } > return crc; > } >=20 > void hash_test(void); > void hash_test(void) > { > printf("CRC of 1 nul byte expected: 0x527d5351\n"); > printf(" soft: %08x\n", crc32c_trivial(null_test, 1, 0)); > rte_hash_crc_init_alg(); > printf(" rte accelerated: %08x\n", ~rte_hash_crc(null_test, 1, > 0xFFFFFFFF)); > rte_hash_crc_set_alg(CRC32_SW); > printf(" rte soft: %08x\n", ~rte_hash_crc(null_test, 1, 0xFFFFFFFF)); >=20 > printf("CRC of 2 nul bytes expected: 0xf16177d2\n"); > printf(" soft: %08x\n", crc32c_trivial(null_test, 2, 0)); > rte_hash_crc_init_alg(); > printf(" rte accelerated: %08x\n", ~rte_hash_crc(null_test, 2, > 0xFFFFFFFF)); > rte_hash_crc_set_alg(CRC32_SW); > printf(" rte soft: %08x\n", ~rte_hash_crc(null_test, 2, 0xFFFFFFFF)); >=20 > printf("CRC of 2x1 nul bytes expected: 0xf16177d2\n"); > printf(" soft: %08x\n", crc32c_trivial(null_test, 1, > crc32c_trivial(null_test, 1, 0))); > rte_hash_crc_init_alg(); > printf(" rte accelerated: %08x\n", ~rte_hash_crc(null_test, 1, > rte_hash_crc(null_test, 1, 0xFFFFFFFF))); > rte_hash_crc_set_alg(CRC32_SW); > printf(" rte soft: %08x\n", ~rte_hash_crc(null_test, 1, > rte_hash_crc(null_test, 1, 0xFFFFFFFF))); >=20 > printf("CRC of 3 nul bytes expected: 0x6064a37a\n"); > printf(" soft: %08x\n", crc32c_trivial(null_test, 3, 0)); > rte_hash_crc_init_alg(); > printf(" rte accelerated: %08x\n", ~rte_hash_crc(null_test, 3, > 0xFFFFFFFF)); > rte_hash_crc_set_alg(CRC32_SW); > printf(" rte soft: %08x\n", ~rte_hash_crc(null_test, 3, 0xFFFFFFFF)); >=20 > printf("CRC of 4 nul bytes expected: 0x48674bc7\n"); > printf(" soft: %08x\n", crc32c_trivial(null_test, 4, 0)); > rte_hash_crc_init_alg(); > printf(" rte accelerated: %08x\n", ~rte_hash_crc(null_test, 4, > 0xFFFFFFFF)); > rte_hash_crc_set_alg(CRC32_SW); > printf(" rte soft: %08x\n", ~rte_hash_crc(null_test, 4, 0xFFFFFFFF)); > } >=20 > Signed-off-by: Didier Pallard > Acked-by: David Marchand It compiles fine now, thanks! Could you add also tests for not multiple of 4 bytes keys in test_hash_func= tions.c, so we make sure from now on that it works (and you can demonstrate that you= r fix works)? You could send a patchset with those new tests first and then the fix. Also, a note in release notes would be welcome :) Thanks! Pablo