test-ssd-write.c

   1 /*
   2  * test-ssd-write.c
   3  *
   4  * Hard disk write workload: write random (or zeroed) data at random
   5  * locations in a file, and optionally validate by re-reading some
   6  * blocks after a while.
   7  *
   8  * Compile with:
   9  * gcc -O2 -Wall -o test-ssd-write test-ssd-write.c
  10  *
  11  * Hard disks known to stop responding with this program (requires a
  12  * warm machine reboot to get the drive to respond, as soft reset is not
  13  * enough):
  14  *
  15  * Vendor         Model          Firmware   Controller     # drives tested
  16  * Intel (Lenovo) SSDSC2BW180A3L LE1i       SandForce 2281 1
  17  * Intel (Lenovo) SSDSC2BW180A3L LF1i       SandForce 2281 3
  18  *
  19  * We ensured that the problem is not coming from other parts by running
  20  * this test on other SSD drives, which don't show this problem:
  21  *
  22  * Vendor         Model          Firmware   Controller     # drives tested
  23  * Intel          SSDSA2M160G2GC 2CV102HD   Intel          1
  24  * Intel          SSDSA2CW300G310 ???????   Intel          1 (over USB on 3.8 kernel)
  25  * Intel          SSDSA2CT040G3  4PC10302   Intel          1 (3.2 kernel)
  26  * Intel          SSDSA2CT040G3  4PC10362   Intel          1 (3.2 kernel)
  27  * Intel          SSDSC2CT120A3K5 ???????   SandForce 2281 1 (on HP SmartArray P212 with 3.2 kernel)
  28  *
  29  * Under Linux (Debian, Ubuntu, various kernels), after about 5 minutes,
  30  * we get this result:
  31  *
  32  * ata1.00: exception Emask 0x0 SAct 0x1 SErr 0x0 action 0x6 frozen
  33  * ata1.00: failed command: WRITE FPDMA QUEUED
  34  * ata1.00: cmd 61/28:00:a8:a9:7f/00:00:02:00:00/40 tag 0 ncq 20480 out
  35  *          res 40/00:00:00:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
  36  * ata1.00: status: { DRDY }
  37  * ata1.00: COMRESET failed (errno=-16)
  38  * ata1.00: COMRESET failed (errno=-16)
  39  *
  40  * This happens with random data, zeroed data (-z), and has been tested
  41  * with file sizes of 1MB, 200MB, 3.1GB and 21GB. The error happens with
  42  * and without the validation (-v) option.
  43  *
  44  * Copyright 2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  45  *
  46  * Permission is hereby granted, free of charge, to any person obtaining
  47  * a copy of this software and associated documentation files (the
  48  * "Software"), to deal in the Software without restriction, including
  49  * without limitation the rights to use, copy, modify, merge, publish,
  50  * distribute, sublicense, and/or sell copies of the Software, and to
  51  * permit persons to whom the Software is furnished to do so, subject to
  52  * the following conditions:
  53  *
  54  * The above copyright notice and this permission notice shall be
  55  * included in all copies or substantial portions of the Software.
  56  *
  57  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  58  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  59  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  60  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  61  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  62  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  63  * SOFTWARE.
  64  */
  65
  66 #include <stdio.h>
  67 #include <sys/types.h>
  68 #include <sys/stat.h>
  69 #include <fcntl.h>
  70 #include <assert.h>
  71 #include <stdlib.h>
  72 #include <unistd.h>
  73 #include <stdint.h>
  74 #include <inttypes.h>
  75 #include <string.h>
  76
  77 enum write_mode {
  78         WRITE_RANDOM = 0,
  79         WRITE_ZEROES,
  80 };
  81
  82 static enum write_mode write_mode;
  83 static int verify_mode;
  84
  85 #define PRINT_FREQ      100000
  86 #define VALIDATE_FREQ   10000
  87 #define BUFLEN          4096
  88
  89 static void rand_buf(char *buf, size_t buflen)
  90 {
  91         size_t i;
  92
  93         for (i = 0; i < buflen; i += sizeof(int)) {
  94                 union {
  95                         int i;
  96                         char c[sizeof(int)];
  97                 } u;
  98                 u.i = rand();
  99                 memcpy(&buf[i], u.c, sizeof(int));
 100         }
 101 }
 102
 103 static uint64_t validate(int fd, const char *validate_buf, off_t offset)
 104 {
 105         char buf[BUFLEN];
 106         ssize_t rret;
 107         off_t pos;
 108         int i;
 109         uint64_t diffcnt = 0;
 110
 111         if (!verify_mode)
 112                 return 0;
 113
 114         pos = lseek(fd, offset, SEEK_SET);
 115         if (pos < 0) {
 116                 perror("lseek");
 117                 exit(EXIT_FAILURE);
 118         }
 119         rret = read(fd, buf, BUFLEN);
 120         if (rret != BUFLEN) {
 121                 fprintf(stderr, "Error at read from offset: %zu\n",
 122                         pos);
 123                 perror("read");
 124                 exit(EXIT_FAILURE);
 125         }
 126         for (i = 0; i < BUFLEN; i++) {
 127                 if (buf[i] != validate_buf[i]) {
 128                         diffcnt++;
 129                 }
 130         }
 131         return diffcnt;
 132 }
 133
 134 static int rand_write(int fd, size_t len)
 135 {
 136         off_t pos, offset;
 137         uint64_t write_nr = 0;
 138         ssize_t wret;
 139         char buf[BUFLEN];
 140         char validate_buf[BUFLEN];
 141         off_t validate_offset = 0;
 142         uint64_t valcount;
 143         int ret;
 144
 145         memset(buf, 0, BUFLEN);
 146
 147         for (;;) {
 148                 if (len > UINT32_MAX) {
 149                         offset = (((size_t) rand() << 32) + (size_t) rand()) % len;
 150                 } else {
 151                         offset = rand() % len;
 152                 }
 153
 154                 if ((offset >= validate_offset &&
 155                         offset < validate_offset + BUFLEN)
 156                         || (validate_offset >= offset &&
 157                                 validate_offset < offset + BUFLEN)) {
 158                         /* Don't overwrite the range we want to validate. */
 159                         continue;
 160                 }
 161                 if (write_mode == WRITE_RANDOM)
 162                         rand_buf(buf, BUFLEN);
 163                 /* Save validation buffer and position */
 164                 if (write_nr % VALIDATE_FREQ == 0 && verify_mode) {
 165                         memcpy(validate_buf, buf, BUFLEN);
 166                         validate_offset = offset;
 167                 }
 168                 pos = lseek(fd, offset, SEEK_SET);
 169                 if (pos < 0) {
 170                         perror("lseek");
 171                         exit(EXIT_FAILURE);
 172                 }
 173                 wret = write(fd, buf, BUFLEN);
 174                 if (wret != BUFLEN) {
 175                         fprintf(stderr, "Error at write to offset: %zu\n",
 176                                 pos);
 177                         perror("write");
 178                         exit(EXIT_FAILURE);
 179                 }
 180
 181                 /*
 182                  * Advise that we won't be re-reading the blocks. This
 183                  * will ask the kernel to drop pages related to this
 184                  * file quickly from its page cache, thus forcing a read
 185                  * from disk.
 186                  */
 187                 ret = fdatasync(fd);
 188                 if (ret) {
 189                         perror("fdatasync");
 190                         exit(EXIT_FAILURE);
 191                 }
 192                 ret = posix_fadvise(fd, offset, BUFLEN, POSIX_FADV_DONTNEED);
 193                 if (ret) {
 194                         perror("posix_fadvise");
 195                         exit(EXIT_FAILURE);
 196                 }
 197
 198                 write_nr++;
 199                 if (write_nr % PRINT_FREQ == 0) {
 200                         printf("Status: %" PRIu64 " writes.\n", write_nr);
 201                 }
 202
 203                 /*
 204                  * Use the validation buffer and position saved
 205                  * VALIDATE_FREQ operations earlier.
 206                  */
 207                 if (write_nr % VALIDATE_FREQ == 0 && verify_mode) {
 208                         valcount = validate(fd, validate_buf, validate_offset);
 209                         if (valcount) {
 210                                 printf("VALIDATION ERROR at offset %zu, %" PRIu64 " bytes differ\n",
 211                                         validate_offset, valcount);
 212                         }
 213                 }
 214         }
 215         return 0;
 216 }
 217
 218 int main(int argc, char **argv)
 219 {
 220         int fd, ret, i, seed;
 221         size_t len;
 222         off_t pos;
 223         ssize_t wret;
 224
 225         if (argc < 4) {
 226                 printf("Usage: %s <output file> <len (64-bit)> <seed (32-bit)> <-z to write zeroes> <-v to verify written data>\n", argv[0]);
 227                 exit(EXIT_FAILURE);
 228         }
 229
 230         fd = open(argv[1], O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
 231         if (fd < 0) {
 232                 perror("open");
 233                 exit(EXIT_FAILURE);
 234         }
 235
 236         len = atoll(argv[2]);
 237         seed = atoi(argv[3]);
 238         srand(seed);
 239
 240         printf("Creating file %s of length %zu, random seed %u\n", argv[1], len,
 241                 seed);
 242
 243         for (i = 4; i < argc; i++) {
 244                 if (strcmp(argv[i], "-z") == 0) {
 245                         write_mode = WRITE_ZEROES;
 246                 } else if (strcmp(argv[i], "-v") == 0) {
 247                         verify_mode = 1;
 248                 }
 249         }
 250
 251         switch (write_mode) {
 252         case WRITE_RANDOM:
 253                 printf("Generating random data\n");
 254                 break;
 255         case WRITE_ZEROES:
 256                 printf("Filling with zeroes (compressible pattern)\n");
 257                 break;
 258         default:
 259                 printf("Unsupported write-mode\n");
 260                 exit(EXIT_FAILURE);
 261         }
 262
 263         if (verify_mode) {
 264                 printf("Verification mode activated.\n");
 265         }
 266
 267         /* Grow file */
 268         pos = lseek(fd, len - 1, SEEK_SET);
 269         if (pos < 0) {
 270                 perror("lseek");
 271                 exit(EXIT_FAILURE);
 272         }
 273         wret = write(fd, "", 1);
 274         if (wret < 0) {
 275                 perror("write");
 276                 exit(EXIT_FAILURE);
 277         }
 278
 279         /* Advise the OS that we are performing random accesses */
 280         ret = posix_fadvise(fd, 0, len, POSIX_FADV_RANDOM);
 281         if (ret) {
 282                 perror("posix_fadvise");
 283                 exit(EXIT_FAILURE);
 284         }
 285
 286         ret = rand_write(fd, len);
 287         if (ret) {
 288                 exit(EXIT_FAILURE);
 289         }
 290
 291         ret = close(fd);
 292         assert(!ret);
 293         exit(EXIT_SUCCESS);
 294 }