[PATCH] selftests/resctrl: Skip MBM&CMT tests when Intel Sub-NUMA

[Shaopeng Tan]

From: "Tan, Shaopeng" <tan.shaopeng@xxxxxxxxxxxxxx>

When the Intel Sub-NUMA Clustering(SNC) feature is enabled,
the CMT and MBM counters may not be accurate.
In this case, skip MBM&CMT tests.

Signed-off-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
---
Hello,

According to the Intel RDT reference Manual, 
when the sub-numa clustering feature is enabled, the CMT and MBM counters may not be accurate.
When running CMT tests and MBM tests on Intel processor, the result is "not ok".
So, fix it to skip the CMT & MBM test When the Intel Sub-NUMA Clustering(SNC) feature is enabled.

Thanks,

 tools/testing/selftests/resctrl/resctrl.h       |  1 +
 tools/testing/selftests/resctrl/resctrl_tests.c | 51 +++++++++++++++++++++++++
 tools/testing/selftests/resctrl/resctrlfs.c     | 26 +++++++++++++
 3 files changed, 78 insertions(+)

diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h
index 1ad10c4..8e82ce3 100644
--- a/tools/testing/selftests/resctrl/resctrl.h
+++ b/tools/testing/selftests/resctrl/resctrl.h
@@ -85,6 +85,7 @@ struct resctrl_val_param {
 int validate_bw_report_request(char *bw_report);
 bool validate_resctrl_feature_request(const char *resctrl_val);
 char *fgrep(FILE *inf, const char *str);
+char *fgrep_last_match_line(FILE *inf, const char *str);
 int taskset_benchmark(pid_t bm_pid, int cpu_no);
 void run_benchmark(int signum, siginfo_t *info, void *ucontext);
 int write_schemata(char *ctrlgrp, char *schemata, int cpu_no,
diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c
index 973f09a..122aab6 100644
--- a/tools/testing/selftests/resctrl/resctrl_tests.c
+++ b/tools/testing/selftests/resctrl/resctrl_tests.c
@@ -8,12 +8,15 @@
  *    Sai Praneeth Prakhya <sai.praneeth.prakhya@xxxxxxxxx>,
  *    Fenghua Yu <fenghua.yu@xxxxxxxxx>
  */
+#include <numa.h>
+#include <string.h>
 #include "resctrl.h"
 
 #define BENCHMARK_ARGS		64
 #define BENCHMARK_ARG_SIZE	64
 
 bool is_amd;
+bool sub_numa_cluster_enable;
 
 void detect_amd(void)
 {
@@ -34,6 +37,35 @@ void detect_amd(void)
 	fclose(inf);
 }
 
+void check_sub_numa_cluster(void)
+{
+	FILE *inf = fopen("/proc/cpuinfo", "r");
+	char *res, *s;
+	int socket_num = 0;
+	int numa_nodes = 0;
+
+	if (!inf)
+		return;
+
+	res = fgrep_last_match_line(inf, "physical id");
+
+	if (res) {
+		s = strpbrk(res, "1234567890");
+		socket_num = atoi(s) + 1;
+		free(res);
+	}
+	fclose(inf);
+
+	numa_nodes = numa_max_node() + 1;
+
+	/*
+	 * when the Sub-NUMA Clustering(SNC) feature is enabled,
+	 * the number of numa nodes is twice the number of sockets.
+	 */
+	if (numa_nodes == (2 * socket_num))
+		sub_numa_cluster_enable = true;
+}
+
 static void cmd_help(void)
 {
 	printf("usage: resctrl_tests [-h] [-b \"benchmark_cmd [options]\"] [-t test list] [-n no_of_bits]\n");
@@ -61,6 +93,13 @@ static void run_mbm_test(bool has_ben, char **benchmark_cmd, int span,
 
 	ksft_print_msg("Starting MBM BW change ...\n");
 
+	/* when the Sub-NUMA Clustering(SNC) feature is enabled,
+	 * the CMT and MBM counters may not be accurate
+	 */
+	if (sub_numa_cluster_enable) {
+		ksft_test_result_skip("Sub-NUMA Clustering(SNC) feature is enabled, the MBM counters may not be accurate.\n");
+		return;
+	}
 	if (!validate_resctrl_feature_request(MBM_STR)) {
 		ksft_test_result_skip("Hardware does not support MBM or MBM is disabled\n");
 		return;
@@ -97,6 +136,14 @@ static void run_cmt_test(bool has_ben, char **benchmark_cmd, int cpu_no)
 	int res;
 
 	ksft_print_msg("Starting CMT test ...\n");
+
+	/* when the Sub-NUMA Clustering(SNC) feature is enabled,
+	 * the CMT and MBM counters may not be accurate
+	 */
+	if (sub_numa_cluster_enable) {
+		ksft_test_result_skip("Sub-NUMA Clustering(SNC) feature is enabled, the CMT counters may not be accurate.\n");
+		return;
+	}
 	if (!validate_resctrl_feature_request(CMT_STR)) {
 		ksft_test_result_skip("Hardware does not support CMT or CMT is disabled\n");
 		return;
@@ -210,6 +257,10 @@ int main(int argc, char **argv)
 	/* Detect AMD vendor */
 	detect_amd();
 
+	/* check whether sub numa clustering is enable or not */
+	if (!is_amd)
+		check_sub_numa_cluster();
+
 	if (has_ben) {
 		/* Extract benchmark command from command line. */
 		for (i = ben_ind; i < argc; i++) {
diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
index 5f5a166..1908ecb 100644
--- a/tools/testing/selftests/resctrl/resctrlfs.c
+++ b/tools/testing/selftests/resctrl/resctrlfs.c
@@ -606,6 +606,32 @@ char *fgrep(FILE *inf, const char *str)
 }
 
 /*
+ * Find the last matched line.
+ * Return a pointer to the string of the matched line,
+ * else retuen NULL if no matched line
+ */
+char *fgrep_last_match_line(FILE *inf, const char *str)
+{
+	char line[256];
+	char result_line[256];
+	int slen = strlen(str);
+
+	while (!feof(inf)) {
+		if (!fgets(line, 256, inf))
+			break;
+		if (strncmp(line, str, slen))
+			continue;
+
+		strcpy(result_line, line);
+	}
+
+	if (strlen(result_line) >= slen)
+		return strdup(result_line);
+
+	return NULL;
+}
+
+/*
  * validate_resctrl_feature_request - Check if requested feature is valid.
  * @resctrl_val:	Requested feature
  *
-- 
1.8.3.1