lustre/include/obd_cksum.h

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  */
  30 /*
  31  * This file is part of Lustre, http://www.lustre.org/
  32  * Lustre is a trademark of Sun Microsystems, Inc.
  33  */
  34
  35 #ifndef __OBD_CKSUM
  36 #define __OBD_CKSUM
  37 #include <libcfs/libcfs.h>
  38 #include <lustre/lustre_idl.h>
  39
  40 static inline unsigned char cksum_obd2cfs(cksum_type_t cksum_type)
  41 {
  42         switch (cksum_type) {
  43         case OBD_CKSUM_CRC32:
  44                 return CFS_HASH_ALG_CRC32;
  45         case OBD_CKSUM_ADLER:
  46                 return CFS_HASH_ALG_ADLER32;
  47         case OBD_CKSUM_CRC32C:
  48                 return CFS_HASH_ALG_CRC32C;
  49         default:
  50                 CERROR("Unknown checksum type (%x)!!!\n", cksum_type);
  51                 LBUG();
  52         }
  53         return 0;
  54 }
  55
  56 /* The OBD_FL_CKSUM_* flags is packed into 5 bits of o_flags, since there can
  57  * only be a single checksum type per RPC.
  58  *
  59  * The OBD_CHECKSUM_* type bits passed in ocd_cksum_types are a 32-bit bitmask
  60  * since they need to represent the full range of checksum algorithms that
  61  * both the client and server can understand.
  62  *
  63  * In case of an unsupported types/flags we fall back to ADLER
  64  * because that is supported by all clients since 1.8
  65  *
  66  * In case multiple algorithms are supported the best one is used. */
  67 static inline obd_flag cksum_type_pack(cksum_type_t cksum_type)
  68 {
  69         unsigned int    performance = 0, tmp;
  70         obd_flag        flag = OBD_FL_CKSUM_ADLER;
  71
  72         if (cksum_type & OBD_CKSUM_CRC32) {
  73                 tmp = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32));
  74                 if (tmp > performance) {
  75                         performance = tmp;
  76                         flag = OBD_FL_CKSUM_CRC32;
  77                 }
  78         }
  79         if (cksum_type & OBD_CKSUM_CRC32C) {
  80                 tmp = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C));
  81                 if (tmp > performance) {
  82                         performance = tmp;
  83                         flag = OBD_FL_CKSUM_CRC32C;
  84                 }
  85         }
  86         if (cksum_type & OBD_CKSUM_ADLER) {
  87                 tmp = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER));
  88                 if (tmp > performance) {
  89                         performance = tmp;
  90                         flag = OBD_FL_CKSUM_ADLER;
  91                 }
  92         }
  93         if (unlikely(cksum_type && !(cksum_type & (OBD_CKSUM_CRC32C |
  94                                                    OBD_CKSUM_CRC32 |
  95                                                    OBD_CKSUM_ADLER))))
  96                 CWARN("unknown cksum type %x\n", cksum_type);
  97
  98         return flag;
  99 }
 100
 101 static inline cksum_type_t cksum_type_unpack(obd_flag o_flags)
 102 {
 103         switch (o_flags & OBD_FL_CKSUM_ALL) {
 104         case OBD_FL_CKSUM_CRC32C:
 105                 return OBD_CKSUM_CRC32C;
 106         case OBD_FL_CKSUM_CRC32:
 107                 return OBD_CKSUM_CRC32;
 108         default:
 109                 break;
 110         }
 111
 112         return OBD_CKSUM_ADLER;
 113 }
 114
 115 /* Return a bitmask of the checksum types supported on this system.
 116  * 1.8 supported ADLER it is base and not depend on hw
 117  * Client uses all available local algos
 118  */
 119 static inline cksum_type_t cksum_types_supported_client(void)
 120 {
 121         cksum_type_t ret = OBD_CKSUM_ADLER;
 122
 123         CDEBUG(D_INFO, "Crypto hash speed: crc %d, crc32c %d, adler %d\n",
 124                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)),
 125                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)),
 126                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER)));
 127
 128         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)) > 0)
 129                 ret |= OBD_CKSUM_CRC32C;
 130         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)) > 0)
 131                 ret |= OBD_CKSUM_CRC32;
 132
 133         return ret;
 134 }
 135
 136 /* Server uses algos that perform at 50% or better of the Adler */
 137 static inline cksum_type_t cksum_types_supported_server(void)
 138 {
 139         int          base_speed;
 140         cksum_type_t    ret = OBD_CKSUM_ADLER;
 141
 142         CDEBUG(D_INFO, "Crypto hash speed: crc %d, crc32c %d, adler %d\n",
 143                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)),
 144                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)),
 145                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER)));
 146
 147         base_speed = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER)) / 2;
 148
 149         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)) >=
 150             base_speed)
 151                 ret |= OBD_CKSUM_CRC32C;
 152         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)) >=
 153             base_speed)
 154                 ret |= OBD_CKSUM_CRC32;
 155
 156         return ret;
 157 }
 158
 159
 160 /* Select the best checksum algorithm among those supplied in the cksum_types
 161  * input.
 162  *
 163  * Currently, calling cksum_type_pack() with a mask will return the fastest
 164  * checksum type due to its benchmarking at libcfs module load.
 165  * Caution is advised, however, since what is fastest on a single client may
 166  * not be the fastest or most efficient algorithm on the server.  */
 167 static inline cksum_type_t cksum_type_select(cksum_type_t cksum_types)
 168 {
 169         return cksum_type_unpack(cksum_type_pack(cksum_types));
 170 }
 171
 172 /* Checksum algorithm names. Must be defined in the same order as the
 173  * OBD_CKSUM_* flags. */
 174 #define DECLARE_CKSUM_NAME char *cksum_name[] = {"crc32", "adler", "crc32c"}
 175
 176 #endif /* __OBD_H */