Andrew's git - gitweb.git/blob - t/helper/test-hash-speed.c

   1#include "test-tool.h"
   2#include "cache.h"
   3
   4#define NUM_SECONDS 3
   5
   6static 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
  13int 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        exit(0);
  61}