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Nothing in the suite checks it's reported correctly. Implement L3_BIT_USAGE to set the root group's CBM to a few masks and confirm that, for every portion, bit_usage marks it software-used exactly when it is in the CBM. With only the root group present this must track the mask bit-for-bit. Signed-off-by: Richard Cheng --- tools/testing/selftests/resctrl/cat_test.c | 153 ++++++++++++++++++ tools/testing/selftests/resctrl/resctrl.h | 1 + .../testing/selftests/resctrl/resctrl_tests.c | 1 + 3 files changed, 155 insertions(+) diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c index d236988916d9..62af8ac98109 100644 --- a/tools/testing/selftests/resctrl/cat_test.c +++ b/tools/testing/selftests/resctrl/cat_test.c @@ -682,3 +682,156 @@ struct resctrl_test l3_cat_validate_test = { .feature_check = test_resource_feature_check, .run_test = cat_validate_run_test, }; + +/* + * L3_BIT_USAGE - Verify info/L3/bit_usage reflects the allocation. + * + * bit_usage annotates each cache portion: 'X'/'S' mean a portion is used by + * software, 'H'/'0' mean it is not. With only the root group present, a + * portion is software-used exactly when it is in the root CBM, so bit_usage + * must track the CBM bit-for-bit. + */ +#define BIT_USAGE_LEN 256 + +static bool bit_usage_sw_used(char c) +{ + return c == 'X' || c == 'S'; +} + +static bool bit_usage_not_used(char c) +{ + return c == 'H' || c == '0'; +} + +static int bit_usage_for_domain(const char *resource, int domain_id, + char *out, size_t len) +{ + char path[1024], raw[BIT_USAGE_LEN], *tok, *save; + FILE *fp; + + snprintf(path, sizeof(path), "%s/%s/bit_usage", INFO_PATH, resource); + fp = fopen(path, "r"); + if (!fp) { + ksft_perror("Error opening bit_usage"); + return -1; + } + if (!fgets(raw, sizeof(raw), fp)) { + ksft_perror("Error reading bit_usage"); + fclose(fp); + return -1; + } + fclose(fp); + + /* bit_usage is "id=chars;id=chars;..."; return the chars for domain_id. */ + for (tok = strtok_r(raw, ";\n", &save); tok; tok = strtok_r(NULL, ";\n", &save)) { + char *eq = strchr(tok, '='); + + if (!eq) + continue; + *eq = '\0'; + if (atoi(tok) == domain_id) { + snprintf(out, len, "%s", eq + 1); + return 0; + } + } + + ksft_print_msg("No bit_usage entry for domain %d\n", domain_id); + return -1; +} + +static int bit_usage_check_mask(const struct resctrl_test *test, int cpu, + int domain_id, unsigned long mask, + int count_of_bits) +{ + char schemata[64], usage[BIT_USAGE_LEN]; + int i, ret; + + snprintf(schemata, sizeof(schemata), "%lx", mask); + ret = write_schemata("", schemata, cpu, test->resource); + if (ret) { + ksft_print_msg("Failed to set CBM 0x%lx\n", mask); + return ret; + } + + ret = bit_usage_for_domain(test->resource, domain_id, usage, sizeof(usage)); + if (ret) + return ret; + + if (strlen(usage) != count_of_bits) { + ksft_print_msg("bit_usage \"%s\" has %zu chars, expected %d\n", + usage, strlen(usage), count_of_bits); + return 1; + } + + /* bit_usage prints the highest portion first, so usage[0] is bit N-1. */ + for (i = 0; i < count_of_bits; i++) { + int bit = count_of_bits - 1 - i; + bool in_cbm = (mask >> bit) & 1; + char c = usage[i]; + + if (!bit_usage_sw_used(c) && !bit_usage_not_used(c)) { + ksft_print_msg("Unexpected bit_usage char '%c' for CBM 0x%lx\n", + c, mask); + return 1; + } + if (in_cbm != bit_usage_sw_used(c)) { + ksft_print_msg("CBM 0x%lx portion %d shows '%c', %s allocation\n", + mask, bit, c, in_cbm ? "in" : "not in"); + return 1; + } + } + + return 0; +} + +static int bit_usage_run_test(const struct resctrl_test *test, + const struct user_params *uparams) +{ + unsigned long full_mask, masks[3]; + char schemata[64]; + int count_of_bits, domain_id, i, ret; + + ret = get_full_cbm(test->resource, &full_mask); + if (ret) + return ret; + + ret = get_domain_id(test->resource, uparams->cpu, &domain_id); + if (ret < 0) + return ret; + + count_of_bits = count_bits(full_mask); + + masks[0] = full_mask; /* every portion */ + masks[1] = create_bit_mask(0, count_of_bits / 2); /* low half */ + masks[2] = full_mask & ~masks[1]; /* high half */ + + for (i = 0; i < 3; i++) { + ret = bit_usage_check_mask(test, uparams->cpu, domain_id, + masks[i], count_of_bits); + if (ret) + break; + } + + /* Restore the root group to the full CBM. */ + snprintf(schemata, sizeof(schemata), "%lx", full_mask); + write_schemata("", schemata, uparams->cpu, test->resource); + + if (!ret) + ksft_print_msg("Pass: bit_usage reflects the allocation\n"); + + return ret; +} + +static bool bit_usage_feature_check(const struct resctrl_test *test) +{ + return test_resource_feature_check(test) && + resource_info_file_exists(test->resource, "bit_usage"); +} + +struct resctrl_test l3_bit_usage_test = { + .name = "L3_BIT_USAGE", + .group = "CAT", + .resource = "L3", + .feature_check = bit_usage_feature_check, + .run_test = bit_usage_run_test, +}; diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index e2e3cf7833bc..270af2b26ba7 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -249,6 +249,7 @@ extern struct resctrl_test cmt_test; extern struct resctrl_test l3_cat_test; extern struct resctrl_test l3_cat_occup_test; extern struct resctrl_test l3_cat_validate_test; +extern struct resctrl_test l3_bit_usage_test; extern struct resctrl_test l3_noncont_cat_test; extern struct resctrl_test l2_noncont_cat_test; diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c index 66739e96f33c..e622928a2d7d 100644 --- a/tools/testing/selftests/resctrl/resctrl_tests.c +++ b/tools/testing/selftests/resctrl/resctrl_tests.c @@ -21,6 +21,7 @@ static struct resctrl_test *resctrl_tests[] = { &l3_cat_test, &l3_cat_occup_test, &l3_cat_validate_test, + &l3_bit_usage_test, &l3_noncont_cat_test, &l2_noncont_cat_test, }; -- 2.43.0