git/t/helper/test-hash-speed.c

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#include "test-tool.h"
#include "cache.h"
#define NUM_SECONDS 3
static inline void compute_hash(const struct git_hash_algo *algo, git_hash_ctx *ctx, uint8_t *final, const void *p, size_t len)
{
algo->init_fn(ctx);
algo->update_fn(ctx, p, len);
algo->final_fn(final, ctx);
}
int cmd__hash_speed(int ac, const char **av)
{
git_hash_ctx ctx;
unsigned char hash[GIT_MAX_RAWSZ];
clock_t initial, start, end;
unsigned bufsizes[] = { 64, 256, 1024, 8192, 16384 };
int i;
void *p;
const struct git_hash_algo *algo = NULL;
if (ac == 2) {
for (i = 1; i < GIT_HASH_NALGOS; i++) {
if (!strcmp(av[1], hash_algos[i].name)) {
algo = &hash_algos[i];
break;
}
}
}
if (!algo)
die("usage: test-tool hash-speed algo_name");
/* Use this as an offset to make overflow less likely. */
initial = clock();
printf("algo: %s\n", algo->name);
for (i = 0; i < ARRAY_SIZE(bufsizes); i++) {
unsigned long j, kb;
double kb_per_sec;
p = xcalloc(1, bufsizes[i]);
start = end = clock() - initial;
for (j = 0; ((end - start) / CLOCKS_PER_SEC) < NUM_SECONDS; j++) {
compute_hash(algo, &ctx, hash, p, bufsizes[i]);
/*
* Only check elapsed time every 128 iterations to avoid
* dominating the runtime with system calls.
*/
if (!(j & 127))
end = clock() - initial;
}
kb = j * bufsizes[i];
kb_per_sec = kb / (1024 * ((double)end - start) / CLOCKS_PER_SEC);
printf("size %u: %lu iters; %lu KiB; %0.2f KiB/s\n", bufsizes[i], j, kb, kb_per_sec);
free(p);
}
return 0;
}