dedupe.c

   1 #include "fio.h"
   2
   3 int init_dedupe_working_set_seeds(struct thread_data *td)
   4 {
   5         unsigned long long i, j, num_seed_advancements;
   6         struct frand_state dedupe_working_set_state = {0};
   7
   8         if (!td->o.dedupe_percentage || !(td->o.dedupe_mode == DEDUPE_MODE_WORKING_SET))
   9                 return 0;
  10
  11         num_seed_advancements = td->o.min_bs[DDIR_WRITE] /
  12                 min_not_zero(td->o.min_bs[DDIR_WRITE], (unsigned long long) td->o.compress_chunk);
  13         /*
  14          * The dedupe working set keeps seeds of unique data (generated by buf_state).
  15          * Dedupe-ed pages will be generated using those seeds.
  16          */
  17         td->num_unique_pages = (td->o.size * (unsigned long long)td->o.dedupe_working_set_percentage / 100) / td->o.min_bs[DDIR_WRITE];
  18         td->dedupe_working_set_states = malloc(sizeof(struct frand_state) * td->num_unique_pages);
  19         if (!td->dedupe_working_set_states) {
  20                 log_err("fio: could not allocate dedupe working set\n");
  21                 return 1;
  22         }
  23         frand_copy(&dedupe_working_set_state, &td->buf_state);
  24         for (i = 0; i < td->num_unique_pages; i++) {
  25                 frand_copy(&td->dedupe_working_set_states[i], &dedupe_working_set_state);
  26                 /*
  27                  * When compression is used the seed is advanced multiple times to
  28                  * generate the buffer. We want to regenerate the same buffer when
  29                  * deduping against this page
  30                  */
  31                 for (j = 0; j < num_seed_advancements; j++)
  32                         __get_next_seed(&dedupe_working_set_state);
  33         }
  34
  35         return 0;
  36 }