t/helper/test-hash-speed.c

   1 #include "test-tool.h"
   2 #include "cache.h"
   3
   4 #define NUM_SECONDS 3
   5
   6 static inline void compute_hash(const struct git_hash_algo *algo, git_hash_ctx *ctx, uint8_t *final, const void *p, size_t len)
   7 {
   8         algo->init_fn(ctx);
   9         algo->update_fn(ctx, p, len);
  10         algo->final_fn(final, ctx);
  11 }
  12
  13 int cmd__hash_speed(int ac, const char **av)
  14 {
  15         git_hash_ctx ctx;
  16         unsigned char hash[GIT_MAX_RAWSZ];
  17         clock_t initial, start, end;
  18         unsigned bufsizes[] = { 64, 256, 1024, 8192, 16384 };
  19         int i;
  20         void *p;
  21         const struct git_hash_algo *algo = NULL;
  22
  23         if (ac == 2) {
  24                 for (i = 1; i < GIT_HASH_NALGOS; i++) {
  25                         if (!strcmp(av[1], hash_algos[i].name)) {
  26                                 algo = &hash_algos[i];
  27                                 break;
  28                         }
  29                 }
  30         }
  31         if (!algo)
  32                 die("usage: test-tool hash-speed algo_name");
  33
  34         /* Use this as an offset to make overflow less likely. */
  35         initial = clock();
  36
  37         printf("algo: %s\n", algo->name);
  38
  39         for (i = 0; i < ARRAY_SIZE(bufsizes); i++) {
  40                 unsigned long j, kb;
  41                 double kb_per_sec;
  42                 p = xcalloc(1, bufsizes[i]);
  43                 start = end = clock() - initial;
  44                 for (j = 0; ((end - start) / CLOCKS_PER_SEC) < NUM_SECONDS; j++) {
  45                         compute_hash(algo, &ctx, hash, p, bufsizes[i]);
  46
  47                         /*
  48                          * Only check elapsed time every 128 iterations to avoid
  49                          * dominating the runtime with system calls.
  50                          */
  51                         if (!(j & 127))
  52                                 end = clock() - initial;
  53                 }
  54                 kb = j * bufsizes[i];
  55                 kb_per_sec = kb / (1024 * ((double)end - start) / CLOCKS_PER_SEC);
  56                 printf("size %u: %lu iters; %lu KiB; %0.2f KiB/s\n", bufsizes[i], j, kb, kb_per_sec);
  57                 free(p);
  58         }
  59
  60         return 0;
  61 }