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