Speed up CRC32 calculations by using a larger lookup table.

Use -DDEBUG_CRC32 to revert to old function and check new one gives same result.

diff --git a/VERSION b/VERSION
index b426edc39c63eb08e083509fbfa388865a1cfe08..7efaa09a1f212cb9420863113b878bc824effa8e 100644 (file)
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.02.74(2)-cvs (2010-09-24)
+2.02.75(2)-cvs (2010-09-24)

diff --git a/VERSION_DM b/VERSION_DM
index 6f7212080a5782dad065c1334d3db9735df92539..06677536fa22863fe005a623d3f59d6f23627f8a 100644 (file)
--- a/VERSION_DM
+++ b/VERSION_DM
@@ -1 +1 @@
-1.02.55-cvs (2010-09-24)
+1.02.56-cvs (2010-09-24)

diff --git a/WHATS_NEW b/WHATS_NEW
index 25e9f330b48066fddb85f1a49c1834f6cf6354e2..51959eb56dab9e9b2f5f2c9ea07c031b3ca096b9 100644 (file)
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,3 +1,7 @@
+Version 2.02.75 - 
+=====================================
+  Speed up CRC32 calculations by using a larger lookup table.
+
 Version 2.02.74 - 24th September 2010
 =====================================
   Allow : and @ to be escaped with \ in device names of PVs.
@@ -17,7 +21,7 @@ Version 2.02.74 - 24th September 2010
   Add configure --with-default-data-alignment.
   Update heuristic used for default and detected data alignment.
   Add "devices/default_data_alignment" to lvm.conf.
-  Add implmentation for simple numeric 'get' property functions.
+  Add implementation for simple numeric 'get' property functions.
   Define GET_NUM_PROPERTY_FN macro to simplify numeric property 'get' function
   Add properties.[ch] to lib/report using columns.h.
   Add macro definitions to report infrastructure for character array length.

diff --git a/WHATS_NEW_DM b/WHATS_NEW_DM
index ef4dfc7b0e3eb9810b8b578647272982aef2770b..892fd6883a4327a53a452dc99f2988711b090fcf 100644 (file)
--- a/WHATS_NEW_DM
+++ b/WHATS_NEW_DM
@@ -1,3 +1,6 @@
+Version 1.02.56 - 
+=====================================
+
 Version 1.02.55 - 24th September 2010
 =====================================
   Fix the way regions are marked complete to avoid slow --nosync cmirror I/O.

diff --git a/lib/config/config.c b/lib/config/config.c
index 333ff78af98a3af97f9c1a89a04f7dcf9aedcb63..72f306d7120e40ec27fb77d61ae179b3877358cb 100644 (file)
--- a/lib/config/config.c
+++ b/lib/config/config.c
@@ -239,8 +239,8 @@ int read_config_fd(struct config_tree *cft, struct device *dev,
        }
 
        if (checksum_fn && checksum !=
-           (checksum_fn(checksum_fn(INITIAL_CRC, p->fb, size),
-                        p->fb + size, size2))) {
+           (checksum_fn(checksum_fn(INITIAL_CRC, (uint8_t *)p->fb, size),
+                        (uint8_t *)(p->fb + size), size2))) {
                log_error("%s: Checksum error", dev_name(dev));
                goto out;
        }

diff --git a/lib/config/config.h b/lib/config/config.h
index da2956b947ad8b7fe5aca35c9d25eafa3b969f19..2d16abdde1669dc8c1feef2ae6e29b04cb723dfb 100644 (file)
--- a/lib/config/config.h
+++ b/lib/config/config.h
@@ -60,7 +60,7 @@ int override_config_tree_from_string(struct cmd_context *cmd,
                                     const char *config_settings);
 void destroy_config_tree(struct config_tree *cft);
 
-typedef uint32_t (*checksum_fn_t) (uint32_t initial, const void *buf, uint32_t size);
+typedef uint32_t (*checksum_fn_t) (uint32_t initial, const uint8_t *buf, uint32_t size);
 
 int read_config_fd(struct config_tree *cft, struct device *dev,
                   off_t offset, size_t size, off_t offset2, size_t size2,

diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c
index 69233608c2386334ea0cbbbae468a4386476a2ee..1a03e84e93a0432796c36d38ffa844c1a420baeb 100644 (file)
--- a/lib/format_text/format-text.c
+++ b/lib/format_text/format-text.c
@@ -332,7 +332,7 @@ struct mda_header *raw_read_mda_header(const struct format_type *fmt,
        if (!dev_read(dev_area->dev, dev_area->start, MDA_HEADER_SIZE, mdah))
                goto_bad;
 
-       if (mdah->checksum_xl != xlate32(calc_crc(INITIAL_CRC, mdah->magic,
+       if (mdah->checksum_xl != xlate32(calc_crc(INITIAL_CRC, (uint8_t *)mdah->magic,
                                                  MDA_HEADER_SIZE -
                                                  sizeof(mdah->checksum_xl)))) {
                log_error("Incorrect metadata area header checksum on %s"
@@ -380,7 +380,7 @@ static int _raw_write_mda_header(const struct format_type *fmt,
        mdah->start = start_byte;
 
        _xlate_mdah(mdah);
-       mdah->checksum_xl = xlate32(calc_crc(INITIAL_CRC, mdah->magic,
+       mdah->checksum_xl = xlate32(calc_crc(INITIAL_CRC, (uint8_t *)mdah->magic,
                                             MDA_HEADER_SIZE -
                                             sizeof(mdah->checksum_xl)));
 
@@ -650,12 +650,12 @@ static int _vg_write_raw(struct format_instance *fid, struct volume_group *vg,
                        goto_out;
        }
 
-       mdac->rlocn.checksum = calc_crc(INITIAL_CRC, fidtc->raw_metadata_buf,
+       mdac->rlocn.checksum = calc_crc(INITIAL_CRC, (uint8_t *)fidtc->raw_metadata_buf,
                                        (uint32_t) (mdac->rlocn.size -
                                                    new_wrap));
        if (new_wrap)
                mdac->rlocn.checksum = calc_crc(mdac->rlocn.checksum,
-                                               fidtc->raw_metadata_buf +
+                                               (uint8_t *)fidtc->raw_metadata_buf +
                                                mdac->rlocn.size -
                                                new_wrap, (uint32_t) new_wrap);
 

diff --git a/lib/label/label.c b/lib/label/label.c
index 9fa505416ecca992f2ab8be5fdb8a1d79a6f1875..9a10d066400c6ace4f14e190d93a5d95f551c4fe 100644 (file)
--- a/lib/label/label.c
+++ b/lib/label/label.c
@@ -142,8 +142,8 @@ static struct labeller *_find_labeller(struct device *dev, char *buf,
                                         sector + scan_sector);
                                continue;
                        }
-                       if (calc_crc(INITIAL_CRC, &lh->offset_xl, LABEL_SIZE -
-                                    ((uintptr_t) &lh->offset_xl - (uintptr_t) lh)) !=
+                       if (calc_crc(INITIAL_CRC, (uint8_t *)&lh->offset_xl, LABEL_SIZE -
+                                    ((uint8_t *) &lh->offset_xl - (uint8_t *) lh)) !=
                            xlate32(lh->crc_xl)) {
                                log_info("Label checksum incorrect on %s - "
                                         "ignoring", dev_name(dev));
@@ -323,8 +323,8 @@ int label_write(struct device *dev, struct label *label)
        if (!(label->labeller->ops->write)(label, buf))
                return_0;
 
-       lh->crc_xl = xlate32(calc_crc(INITIAL_CRC, &lh->offset_xl, LABEL_SIZE -
-                                     ((uintptr_t) &lh->offset_xl - (uintptr_t) lh)));
+       lh->crc_xl = xlate32(calc_crc(INITIAL_CRC, (uint8_t *)&lh->offset_xl, LABEL_SIZE -
+                                     ((uint8_t *) &lh->offset_xl - (uint8_t *) lh)));
 
        if (!dev_open(dev))
                return_0;

diff --git a/lib/misc/crc.c b/lib/misc/crc.c
index c69ee9303f22afd4484ff3e7bfe7db4c41d0573f..75d1c60e11ba507033de44dafcade57ff9a2af8e 100644 (file)
--- a/lib/misc/crc.c
+++ b/lib/misc/crc.c
@@ -18,7 +18,73 @@
 #include "crc.h"
 
 /* Calculate an endian-independent CRC of supplied buffer */
-uint32_t calc_crc(uint32_t initial, const void *buf, uint32_t size)
+#ifndef DEBUG_CRC32
+uint32_t calc_crc(uint32_t initial, const uint8_t *buf, uint32_t size)
+#else
+static uint32_t _calc_crc_new(uint32_t initial, const uint8_t *buf, uint32_t size)
+#endif
+{
+       /* CRC-32 byte lookup table generated by crcgen.c */
+       static const uint32_t crctab[] = {
+               0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
+               0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
+               0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+               0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
+               0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+               0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+               0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
+               0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
+               0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+               0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+               0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
+               0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+               0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
+               0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
+               0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+               0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
+               0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
+               0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+               0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
+               0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+               0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+               0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
+               0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
+               0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+               0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+               0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
+               0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+               0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
+               0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
+               0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+               0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
+               0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d,
+       };
+       uint32_t *start = (uint32_t *) buf;
+       uint32_t *end = (uint32_t *) (buf + (size & 0xfffffffc));
+       uint32_t crc = initial;
+   
+       /* Process 4 bytes per iteration */
+       while (start < end) {
+               crc = crc ^ *start++;
+               crc = crctab[crc & 0xff] ^ crc >> 8;
+               crc = crctab[crc & 0xff] ^ crc >> 8;
+               crc = crctab[crc & 0xff] ^ crc >> 8;
+               crc = crctab[crc & 0xff] ^ crc >> 8;
+       }
+
+       /* Process any bytes left over */
+       buf = (uint8_t *) start;
+       size = size & 0x3;
+       while (size--) {
+               crc = crc ^ *buf++;
+               crc = crctab[crc & 0xff] ^ crc >> 8;
+       }
+
+       return crc;
+}
+
+#ifdef DEBUG_CRC32
+static uint32_t _calc_crc_old(uint32_t initial, const uint8_t *buf, uint32_t size)
 {
        static const uint32_t crctab[] = {
                0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
@@ -27,12 +93,24 @@ uint32_t calc_crc(uint32_t initial, const void *buf, uint32_t size)
                0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
        };
        uint32_t i, crc = initial;
-       const uint8_t *data = (const uint8_t *) buf;
 
        for (i = 0; i < size; i++) {
-               crc ^= *data++;
+               crc ^= *buf++;
                crc = (crc >> 4) ^ crctab[crc & 0xf];
                crc = (crc >> 4) ^ crctab[crc & 0xf];
        }
        return crc;
 }
+
+uint32_t calc_crc(uint32_t initial, const uint8_t *buf, uint32_t size)
+{
+       uint32_t new_crc = _calc_crc_new(initial, buf, size);
+       uint32_t old_crc = _calc_crc_old(initial, buf, size);
+
+       if (new_crc != old_crc)
+               log_error(INTERNAL_ERROR "Old and new crc32 algorithms mismatch: 0x%08x != 0x%08x", old_crc, new_crc);
+
+       return old_crc;
+}
+
+#endif /* DEBUG_CRC32 */

diff --git a/lib/misc/crc.h b/lib/misc/crc.h
index f7f99423a0b778627e2429f10199659e981b90b9..2910bc55bf31a7240106c03b098f40ab2c93b375 100644 (file)
--- a/lib/misc/crc.h
+++ b/lib/misc/crc.h
@@ -18,6 +18,6 @@
 
 #define INITIAL_CRC 0xf597a6cf
 
-uint32_t calc_crc(uint32_t initial, const void *buf, uint32_t size);
+uint32_t calc_crc(uint32_t initial, const uint8_t *buf, uint32_t size);
 
 #endif

diff --git a/lib/misc/crc_gen.c b/lib/misc/crc_gen.c
new file mode 100644 (file)
index 0000000..846cca9
--- /dev/null
+++ b/lib/misc/crc_gen.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2010 Red Hat, Inc. All rights reserved.
+ *
+ * This file is part of LVM2.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License v.2.1.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+/*
+ * Helper program to generate table included in crc.c.
+ */
+#include "lib.h"
+
+int main(int argc, char **argv)
+{
+       uint32_t crc, i, j;
+
+       printf("\t/* CRC-32 byte lookup table generated by crcgen.c */\n");
+       printf("\tstatic const uint32_t crctab[] = {");
+
+       for (i = 0; i < 256; i++) {
+               crc = i;
+               for (j = 0; j < 8; j++) {
+                       if (crc & 1)
+                               crc = 0xedb88320L ^ (crc >> 1);
+                       else
+                               crc = crc >> 1;
+               }
+
+               if (i % 8)
+                       printf(" ");
+               else
+                       printf("\n\t\t");
+
+               printf("0x%08.8x,", crc);
+       }
+
+       printf("\n\t};\n");
+
+       return 0;
+}

diff --git a/make.tmpl.in b/make.tmpl.in
index 7cb0f6f09a6bbd69bf7fa111a3e8750dd494d6b9..d30da1a8b57b38d7474634ff17edbaef5ac88cc1 100644 (file)
--- a/make.tmpl.in
+++ b/make.tmpl.in
@@ -113,6 +113,7 @@ CFLAGS += -fPIC -Wall -Wundef -Wshadow -Wcast-align -Wwrite-strings -Wmissing-pr
 
 #CFLAGS += -W -Wconversion -Wpointer-arith -Wbad-function-cast -Wcast-qual
 #CFLAGS += -pedantic -std=gnu99
+#CFLAGS += -DDEBUG_CRC32
 
 CFLAGS += @COPTIMISE_FLAG@