From d6d35d0b0f4267612eb905305f3f2f7aa048bfd4 Mon Sep 17 00:00:00 2001 From: Maciej Wieczor-Retman Date: Mon, 16 Dec 2024 16:18:54 +0100 Subject: [PATCH] selftests/resctrl: Discover SNC kernel support and adjust messages Resctrl selftest prints a message on test failure that Sub-Numa Clustering (SNC) could be enabled and points the user to check their BIOS settings. No actual check is performed before printing that message so it is not very accurate in pinpointing a problem. When there is SNC support for kernel's resctrl subsystem and SNC is enabled then sub node files are created for each node in the resctrlfs. The sub node files exist in each regular node's L3 monitoring directory. The reliable path to check for existence of sub node files is /sys/fs/resctrl/mon_data/mon_L3_00/mon_sub_L3_00. Add helper that checks for mon_sub_L3_00 existence. Correct old messages to account for kernel support of SNC in resctrl. Signed-off-by: Maciej Wieczor-Retman Reviewed-by: Reinette Chatre Signed-off-by: Shuah Khan --- tools/testing/selftests/resctrl/cmt_test.c | 4 +-- tools/testing/selftests/resctrl/mba_test.c | 2 ++ tools/testing/selftests/resctrl/mbm_test.c | 4 +-- tools/testing/selftests/resctrl/resctrl.h | 1 + tools/testing/selftests/resctrl/resctrlfs.c | 32 +++++++++++++++++++++ 5 files changed, 39 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/resctrl/cmt_test.c b/tools/testing/selftests/resctrl/cmt_test.c index 3bbf3042fb06e..d09e693dc739c 100644 --- a/tools/testing/selftests/resctrl/cmt_test.c +++ b/tools/testing/selftests/resctrl/cmt_test.c @@ -169,8 +169,8 @@ static int cmt_run_test(const struct resctrl_test *test, const struct user_param return ret; ret = check_results(¶m, span, n); - if (ret && (get_vendor() == ARCH_INTEL)) - ksft_print_msg("Intel CMT may be inaccurate when Sub-NUMA Clustering is enabled. Check BIOS configuration.\n"); + if (ret && (get_vendor() == ARCH_INTEL) && !snc_kernel_support()) + ksft_print_msg("Kernel doesn't support Sub-NUMA Clustering but it is enabled on the system.\n"); return ret; } diff --git a/tools/testing/selftests/resctrl/mba_test.c b/tools/testing/selftests/resctrl/mba_test.c index 536d9089d2f6c..c7e9adc0368f3 100644 --- a/tools/testing/selftests/resctrl/mba_test.c +++ b/tools/testing/selftests/resctrl/mba_test.c @@ -201,6 +201,8 @@ static int mba_run_test(const struct resctrl_test *test, const struct user_param return ret; ret = check_results(); + if (ret && (get_vendor() == ARCH_INTEL) && !snc_kernel_support()) + ksft_print_msg("Kernel doesn't support Sub-NUMA Clustering but it is enabled on the system.\n"); return ret; } diff --git a/tools/testing/selftests/resctrl/mbm_test.c b/tools/testing/selftests/resctrl/mbm_test.c index 315b2ef3b3bcb..84d8bc2505392 100644 --- a/tools/testing/selftests/resctrl/mbm_test.c +++ b/tools/testing/selftests/resctrl/mbm_test.c @@ -160,8 +160,8 @@ static int mbm_run_test(const struct resctrl_test *test, const struct user_param return ret; ret = check_results(param.fill_buf ? param.fill_buf->buf_size : 0); - if (ret && (get_vendor() == ARCH_INTEL)) - ksft_print_msg("Intel MBM may be inaccurate when Sub-NUMA Clustering is enabled. Check BIOS configuration.\n"); + if (ret && (get_vendor() == ARCH_INTEL) && !snc_kernel_support()) + ksft_print_msg("Kernel doesn't support Sub-NUMA Clustering but it is enabled on the system.\n"); return ret; } diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index 35fa3afee9c3c..cd3adfc14969f 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -203,6 +203,7 @@ void ctrlc_handler(int signum, siginfo_t *info, void *ptr); int signal_handler_register(const struct resctrl_test *test); void signal_handler_unregister(void); unsigned int count_bits(unsigned long n); +int snc_kernel_support(void); void perf_event_attr_initialize(struct perf_event_attr *pea, __u64 config); void perf_event_initialize_read_format(struct perf_event_read *pe_read); diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c index dc7ce3cbdb271..195f04c4d1586 100644 --- a/tools/testing/selftests/resctrl/resctrlfs.c +++ b/tools/testing/selftests/resctrl/resctrlfs.c @@ -957,3 +957,35 @@ unsigned int count_bits(unsigned long n) return count; } + +/** + * snc_kernel_support - Check for existence of mon_sub_L3_00 file that indicates + * SNC resctrl support on the kernel side. + * + * Return: 0 if not supported, 1 if SNC is disabled or SNC discovery is + * unreliable or SNC is both enabled and supported. + */ +int snc_kernel_support(void) +{ + char node_path[PATH_MAX]; + struct stat statbuf; + int ret; + + ret = snc_nodes_per_l3_cache(); + /* + * If SNC is disabled then its kernel support isn't important. If SNC + * got disabled because the discovery process was unreliable the + * snc_unreliable variable was set. It can be used to verify the SNC + * discovery reliability elsewhere in the selftest. + */ + if (ret == 1) + return ret; + + snprintf(node_path, sizeof(node_path), "%s/%s", RESCTRL_PATH, + "mon_data/mon_L3_00/mon_sub_L3_00"); + + if (!stat(node_path, &statbuf)) + return 1; + + return 0; +}