diff options
| -rw-r--r-- | t/helper/test-path-utils.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/t/helper/test-path-utils.c b/t/helper/test-path-utils.c index 94846550f7..16d8e689c8 100644 --- a/t/helper/test-path-utils.c +++ b/t/helper/test-path-utils.c @@ -176,6 +176,99 @@ static int is_dotgitmodules(const char *path) return is_hfs_dotgitmodules(path) || is_ntfs_dotgitmodules(path); } +/* + * A very simple, reproducible pseudo-random generator. Copied from + * `test-genrandom.c`. + */ +static uint64_t my_random_value = 1234; + +static uint64_t my_random(void) +{ + my_random_value = my_random_value * 1103515245 + 12345; + return my_random_value; +} + +/* + * A fast approximation of the square root, without requiring math.h. + * + * It uses Newton's method to approximate the solution of 0 = x^2 - value. + */ +static double my_sqrt(double value) +{ + const double epsilon = 1e-6; + double x = value; + + if (value == 0) + return 0; + + for (;;) { + double delta = (value / x - x) / 2; + if (delta < epsilon && delta > -epsilon) + return x + delta; + x += delta; + } +} + +static int protect_ntfs_hfs_benchmark(int argc, const char **argv) +{ + size_t i, j, nr, min_len = 3, max_len = 20; + char **names; + int repetitions = 15, file_mode = 0100644; + uint64_t begin, end; + double m[3][2], v[3][2]; + uint64_t cumul; + double cumul2; + + if (argc > 1 && !strcmp(argv[1], "--with-symlink-mode")) { + file_mode = 0120000; + argc--; + argv++; + } + + nr = argc > 1 ? strtoul(argv[1], NULL, 0) : 1000000; + ALLOC_ARRAY(names, nr); + + if (argc > 2) { + min_len = strtoul(argv[2], NULL, 0); + if (argc > 3) + max_len = strtoul(argv[3], NULL, 0); + if (min_len > max_len) + die("min_len > max_len"); + } + + for (i = 0; i < nr; i++) { + size_t len = min_len + (my_random() % (max_len + 1 - min_len)); + + names[i] = xmallocz(len); + while (len > 0) + names[i][--len] = (char)(' ' + (my_random() % ('\x7f' - ' '))); + } + + for (protect_ntfs = 0; protect_ntfs < 2; protect_ntfs++) + for (protect_hfs = 0; protect_hfs < 2; protect_hfs++) { + cumul = 0; + cumul2 = 0; + for (i = 0; i < repetitions; i++) { + begin = getnanotime(); + for (j = 0; j < nr; j++) + verify_path(names[j], file_mode); + end = getnanotime(); + printf("protect_ntfs = %d, protect_hfs = %d: %lfms\n", protect_ntfs, protect_hfs, (end-begin) / (double)1e6); + cumul += end - begin; + cumul2 += (end - begin) * (end - begin); + } + m[protect_ntfs][protect_hfs] = cumul / (double)repetitions; + v[protect_ntfs][protect_hfs] = my_sqrt(cumul2 / (double)repetitions - m[protect_ntfs][protect_hfs] * m[protect_ntfs][protect_hfs]); + printf("mean: %lfms, stddev: %lfms\n", m[protect_ntfs][protect_hfs] / (double)1e6, v[protect_ntfs][protect_hfs] / (double)1e6); + } + + for (protect_ntfs = 0; protect_ntfs < 2; protect_ntfs++) + for (protect_hfs = 0; protect_hfs < 2; protect_hfs++) + printf("ntfs=%d/hfs=%d: %lf%% slower\n", protect_ntfs, protect_hfs, (m[protect_ntfs][protect_hfs] - m[0][0]) * 100 / m[0][0]); + + return 0; +} + int cmd_main(int argc, const char **argv) { if (argc == 3 && !strcmp(argv[1], "normalize_path_copy")) { @@ -290,6 +383,9 @@ int cmd_main(int argc, const char **argv) return !!res; } + if (argc > 1 && !strcmp(argv[1], "protect_ntfs_hfs")) + return !!protect_ntfs_hfs_benchmark(argc - 1, argv + 1); + fprintf(stderr, "%s: unknown function name: %s\n", argv[0], argv[1] ? argv[1] : "(there was none)"); return 1; |