Merge tag 'linux_kselftest-next-7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull kselftest updates from Shuah Khan:
 "Several fixes and improvements to resctrl tests and a change to
  kselftest document to clarify the use of FORCE_TARGETS build variable"

* tag 'linux_kselftest-next-7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  kselftest: fix doc for ksft_test_result_report()
  selftests/resctrl: Reduce L2 impact on CAT test
  selftests/resctrl: Simplify perf usage in CAT test
  selftests/resctrl: Remove requirement on cache miss rate
  selftests/resctrl: Raise threshold at which MBM and PMU values are compared
  selftests/resctrl: Increase size of buffer used in MBM and MBA tests
  selftests/resctrl: Support multiple events associated with iMC
  selftests/resctrl: Prepare for parsing multiple events per iMC
  selftests/resctrl: Do not store iMC counter value in counter config structure
  selftests/resctrl: Reduce interference from L2 occupancy during cache occupancy test
  selftests/resctrl: Improve accuracy of cache occupancy test
  docs: kselftest: Document the FORCE_TARGETS build variable

Documentation/dev-tools/kselftest.rst

@@ -126,6 +126,18 @@ dedicated skiplist::
 See the top-level tools/testing/selftests/Makefile for the list of all
 possible targets.
 
+Requiring all targets to build successfully
+===========================================
+
+By default, the build succeeds as long as at least one target builds
+without error. Set ``FORCE_TARGETS=1`` to instead require every target to
+build successfully; make will abort as soon as any target fails::
+
+  $ make -C tools/testing/selftests FORCE_TARGETS=1
+
+This applies to both the ``all`` and ``install`` targets and is useful in
+CI environments where a silent partial build would be misleading.
+
 Running the full range hotplug selftests
 ========================================
 

tools/testing/selftests/kselftest.h

@@ -346,9 +346,9 @@ void ksft_test_result_code(int exit_code, const char *test_name,
 }
 
 /**
- * ksft_test_result() - Report test success based on truth of condition
+ * ksft_test_result_report() - Report test result based on a kselftest exit code
  *
- * @condition: if true, report test success, otherwise failure.
+ * @result: a kselftest exit code
  */
 #define ksft_test_result_report(result, fmt, ...) do {		\
 	switch (result) {					\

tools/testing/selftests/resctrl/cache.c

@@ -10,7 +10,6 @@ void perf_event_attr_initialize(struct perf_event_attr *pea, __u64 config)
 	memset(pea, 0, sizeof(*pea));
 	pea->type = PERF_TYPE_HARDWARE;
 	pea->size = sizeof(*pea);
-	pea->read_format = PERF_FORMAT_GROUP;
 	pea->exclude_kernel = 1;
 	pea->exclude_hv = 1;
 	pea->exclude_idle = 1;
@@ -37,19 +36,13 @@ int perf_event_reset_enable(int pe_fd)
 	return 0;
 }
 
-void perf_event_initialize_read_format(struct perf_event_read *pe_read)
-{
-	memset(pe_read, 0, sizeof(*pe_read));
-	pe_read->nr = 1;
-}
-
 int perf_open(struct perf_event_attr *pea, pid_t pid, int cpu_no)
 {
 	int pe_fd;
 
 	pe_fd = perf_event_open(pea, pid, cpu_no, -1, PERF_FLAG_FD_CLOEXEC);
 	if (pe_fd == -1) {
-		ksft_perror("Error opening leader");
+		ksft_perror("Unable to set up performance monitoring");
 		return -1;
 	}
 
@@ -132,9 +125,9 @@ static int print_results_cache(const char *filename, pid_t bm_pid, __u64 llc_val
  *
  * Return: =0 on success. <0 on failure.
  */
-int perf_event_measure(int pe_fd, struct perf_event_read *pe_read,
-		       const char *filename, pid_t bm_pid)
+int perf_event_measure(int pe_fd, const char *filename, pid_t bm_pid)
 {
+	__u64 value;
 	int ret;
 
 	/* Stop counters after one span to get miss rate */
@@ -142,13 +135,13 @@ int perf_event_measure(int pe_fd, struct perf_event_read *pe_read,
 	if (ret < 0)
 		return ret;
 
-	ret = read(pe_fd, pe_read, sizeof(*pe_read));
+	ret = read(pe_fd, &value, sizeof(value));
 	if (ret == -1) {
 		ksft_perror("Could not get perf value");
 		return -1;
 	}
 
-	return print_results_cache(filename, bm_pid, pe_read->values[0].value);
+	return print_results_cache(filename, bm_pid, value);
 }
 
 /*
@@ -173,6 +166,19 @@ int measure_llc_resctrl(const char *filename, pid_t bm_pid)
 	return print_results_cache(filename, bm_pid, llc_occu_resc);
 }
 
+/*
+ * Reduce L2 allocation to minimum when testing L3 cache allocation.
+ */
+int minimize_l2_occupancy(const struct resctrl_test *test,
+			  const struct user_params *uparams,
+			  const struct resctrl_val_param *param)
+{
+	if (!strcmp(test->resource, "L3") && resctrl_resource_exists("L2"))
+		return write_schemata(param->ctrlgrp, "0x1", uparams->cpu, "L2");
+
+	return 0;
+}
+
 /*
  * show_cache_info - Show generic cache test information
  * @no_of_bits:		Number of bits

tools/testing/selftests/resctrl/cat_test.c

@@ -14,42 +14,20 @@
 #define RESULT_FILE_NAME	"result_cat"
 #define NUM_OF_RUNS		5
 
-/*
- * Minimum difference in LLC misses between a test with n+1 bits CBM to the
- * test with n bits is MIN_DIFF_PERCENT_PER_BIT * (n - 1). With e.g. 5 vs 4
- * bits in the CBM mask, the minimum difference must be at least
- * MIN_DIFF_PERCENT_PER_BIT * (4 - 1) = 3 percent.
- *
- * The relationship between number of used CBM bits and difference in LLC
- * misses is not expected to be linear. With a small number of bits, the
- * margin is smaller than with larger number of bits. For selftest purposes,
- * however, linear approach is enough because ultimately only pass/fail
- * decision has to be made and distinction between strong and stronger
- * signal is irrelevant.
- */
-#define MIN_DIFF_PERCENT_PER_BIT	1UL
-
 static int show_results_info(__u64 sum_llc_val, int no_of_bits,
 			     unsigned long cache_span,
-			     unsigned long min_diff_percent,
 			     unsigned long num_of_runs, bool platform,
 			     __s64 *prev_avg_llc_val)
 {
 	__u64 avg_llc_val = 0;
-	float avg_diff;
 	int ret = 0;
 
 	avg_llc_val = sum_llc_val / num_of_runs;
 	if (*prev_avg_llc_val) {
-		float delta = (__s64)(avg_llc_val - *prev_avg_llc_val);
+		ret = platform && (avg_llc_val < *prev_avg_llc_val);
 
-		avg_diff = delta / *prev_avg_llc_val;
-		ret = platform && (avg_diff * 100) < (float)min_diff_percent;
-
-		ksft_print_msg("%s Check cache miss rate changed more than %.1f%%\n",
-			       ret ? "Fail:" : "Pass:", (float)min_diff_percent);
-
-		ksft_print_msg("Percent diff=%.1f\n", avg_diff * 100);
+		ksft_print_msg("%s Check cache miss rate increased\n",
+			       ret ? "Fail:" : "Pass:");
 	}
 	*prev_avg_llc_val = avg_llc_val;
 
@@ -58,10 +36,10 @@ static int show_results_info(__u64 sum_llc_val, int no_of_bits,
 	return ret;
 }
 
-/* Remove the highest bit from CBM */
+/* Remove the highest bits from CBM */
 static unsigned long next_mask(unsigned long current_mask)
 {
-	return current_mask & (current_mask >> 1);
+	return current_mask & (current_mask >> 2);
 }
 
 static int check_results(struct resctrl_val_param *param, const char *cache_type,
@@ -112,7 +90,6 @@ static int check_results(struct resctrl_val_param *param, const char *cache_type
 
 		ret = show_results_info(sum_llc_perf_miss, bits,
 					alloc_size / 64,
-					MIN_DIFF_PERCENT_PER_BIT * (bits - 1),
 					runs, get_vendor() == ARCH_INTEL,
 					&prev_avg_llc_val);
 		if (ret)
@@ -158,7 +135,6 @@ static int cat_test(const struct resctrl_test *test,
 		    struct resctrl_val_param *param,
 		    size_t span, unsigned long current_mask)
 {
-	struct perf_event_read pe_read;
 	struct perf_event_attr pea;
 	cpu_set_t old_affinity;
 	unsigned char *buf;
@@ -181,8 +157,11 @@ static int cat_test(const struct resctrl_test *test,
 	if (ret)
 		goto reset_affinity;
 
+	ret = minimize_l2_occupancy(test, uparams, param);
+	if (ret)
+		goto reset_affinity;
+
 	perf_event_attr_initialize(&pea, PERF_COUNT_HW_CACHE_MISSES);
-	perf_event_initialize_read_format(&pe_read);
 	pe_fd = perf_open(&pea, bm_pid, uparams->cpu);
 	if (pe_fd < 0) {
 		ret = -1;
@@ -215,7 +194,7 @@ static int cat_test(const struct resctrl_test *test,
 
 			fill_cache_read(buf, span, true);
 
-			ret = perf_event_measure(pe_fd, &pe_read, param->filename, bm_pid);
+			ret = perf_event_measure(pe_fd, param->filename, bm_pid);
 			if (ret)
 				goto free_buf;
 		}

tools/testing/selftests/resctrl/cmt_test.c

@@ -19,12 +19,40 @@
 #define CON_MON_LCC_OCCUP_PATH		\
 	"%s/%s/mon_data/mon_L3_%02d/llc_occupancy"
 
-static int cmt_init(const struct resctrl_val_param *param, int domain_id)
+/*
+ * Initialize capacity bitmasks (CBMs) of:
+ * - control group being tested per test parameters,
+ * - default resource group as inverse of control group being tested to prevent
+ *   other tasks from interfering with test,
+ * - L2 resource of control group being tested to minimize allocations into
+ *   L2 if possible to better predict L3 occupancy.
+ */
+static int cmt_init(const struct resctrl_test *test,
+		    const struct user_params *uparams,
+		    const struct resctrl_val_param *param, int domain_id)
 {
+	unsigned long full_mask;
+	char schemata[64];
+	int ret;
+
 	sprintf(llc_occup_path, CON_MON_LCC_OCCUP_PATH, RESCTRL_PATH,
 		param->ctrlgrp, domain_id);
 
-	return 0;
+	ret = get_full_cbm(test->resource, &full_mask);
+	if (ret)
+		return ret;
+
+	snprintf(schemata, sizeof(schemata), "%lx", ~param->mask & full_mask);
+	ret = write_schemata("", schemata, uparams->cpu, test->resource);
+	if (ret)
+		return ret;
+
+	snprintf(schemata, sizeof(schemata), "%lx", param->mask);
+	ret = write_schemata(param->ctrlgrp, schemata, uparams->cpu, test->resource);
+	if (ret)
+		return ret;
+
+	return minimize_l2_occupancy(test, uparams, param);
 }
 
 static int cmt_setup(const struct resctrl_test *test,
@@ -153,11 +181,11 @@ static int cmt_run_test(const struct resctrl_test *test, const struct user_param
 	span = cache_portion_size(cache_total_size, param.mask, long_mask);
 
 	if (uparams->fill_buf) {
-		fill_buf.buf_size = span;
+		fill_buf.buf_size = span * 2;
 		fill_buf.memflush = uparams->fill_buf->memflush;
 		param.fill_buf = &fill_buf;
 	} else if (!uparams->benchmark_cmd[0]) {
-		fill_buf.buf_size = span;
+		fill_buf.buf_size = span * 2;
 		fill_buf.memflush = true;
 		param.fill_buf = &fill_buf;
 	}

tools/testing/selftests/resctrl/fill_buf.c

@@ -139,6 +139,6 @@ ssize_t get_fill_buf_size(int cpu_no, const char *cache_type)
 	if (ret)
 		return ret;
 
-	return cache_total_size * 2 > MINIMUM_SPAN ?
-			cache_total_size * 2 : MINIMUM_SPAN;
+	return cache_total_size * 4 > MINIMUM_SPAN ?
+			cache_total_size * 4 : MINIMUM_SPAN;
 }

tools/testing/selftests/resctrl/mba_test.c

@@ -12,12 +12,14 @@
 
 #define RESULT_FILE_NAME	"result_mba"
 #define NUM_OF_RUNS		5
-#define MAX_DIFF_PERCENT	8
+#define MAX_DIFF_PERCENT	15
 #define ALLOCATION_MAX		100
 #define ALLOCATION_MIN		10
 #define ALLOCATION_STEP		10
 
-static int mba_init(const struct resctrl_val_param *param, int domain_id)
+static int mba_init(const struct resctrl_test *test,
+		    const struct user_params *uparams,
+		    const struct resctrl_val_param *param, int domain_id)
 {
 	int ret;
 

tools/testing/selftests/resctrl/mbm_test.c

@@ -11,7 +11,7 @@
 #include "resctrl.h"
 
 #define RESULT_FILE_NAME	"result_mbm"
-#define MAX_DIFF_PERCENT	8
+#define MAX_DIFF_PERCENT	15
 #define NUM_OF_RUNS		5
 
 static int
@@ -83,7 +83,9 @@ static int check_results(size_t span)
 	return ret;
 }
 
-static int mbm_init(const struct resctrl_val_param *param, int domain_id)
+static int mbm_init(const struct resctrl_test *test,
+		    const struct user_params *uparams,
+		    const struct resctrl_val_param *param, int domain_id)
 {
 	int ret;
 

tools/testing/selftests/resctrl/resctrl.h

@@ -55,7 +55,7 @@
  * and MBM respectively, for instance generating "overhead" traffic which
  * is not counted against any specific RMID.
  */
-#define THROTTLE_THRESHOLD	750
+#define THROTTLE_THRESHOLD	2500
 
 /*
  * fill_buf_param:	"fill_buf" benchmark parameters
@@ -135,7 +135,9 @@ struct resctrl_val_param {
 	char			filename[64];
 	unsigned long		mask;
 	int			num_of_runs;
-	int			(*init)(const struct resctrl_val_param *param,
+	int			(*init)(const struct resctrl_test *test,
+					const struct user_params *uparams,
+					const struct resctrl_val_param *param,
 					int domain_id);
 	int			(*setup)(const struct resctrl_test *test,
 					 const struct user_params *uparams,
@@ -146,13 +148,6 @@ struct resctrl_val_param {
 	struct fill_buf_param	*fill_buf;
 };
 
-struct perf_event_read {
-	__u64 nr;			/* The number of events */
-	struct {
-		__u64 value;		/* The value of the event */
-	} values[2];
-};
-
 /*
  * Memory location that consumes values compiler must not optimize away.
  * Volatile ensures writes to this location cannot be optimized away by
@@ -208,12 +203,13 @@ 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);
 int perf_open(struct perf_event_attr *pea, pid_t pid, int cpu_no);
 int perf_event_reset_enable(int pe_fd);
-int perf_event_measure(int pe_fd, struct perf_event_read *pe_read,
-		       const char *filename, pid_t bm_pid);
+int perf_event_measure(int pe_fd, const char *filename, pid_t bm_pid);
 int measure_llc_resctrl(const char *filename, pid_t bm_pid);
+int minimize_l2_occupancy(const struct resctrl_test *test,
+			  const struct user_params *uparams,
+			  const struct resctrl_val_param *param);
 void show_cache_info(int no_of_bits, __u64 avg_llc_val, size_t cache_span, bool lines);
 
 /*

tools/testing/selftests/resctrl/resctrl_val.c

@@ -11,10 +11,10 @@
 #include "resctrl.h"
 
 #define UNCORE_IMC		"uncore_imc"
-#define READ_FILE_NAME		"events/cas_count_read"
+#define READ_FILE_NAME		"cas_count_read"
 #define DYN_PMU_PATH		"/sys/bus/event_source/devices"
 #define SCALE			0.00006103515625
-#define MAX_IMCS		20
+#define MAX_IMCS		40
 #define MAX_TOKENS		5
 
 #define CON_MBM_LOCAL_BYTES_PATH		\
@@ -32,7 +32,6 @@ struct imc_counter_config {
 	__u64 event;
 	__u64 umask;
 	struct perf_event_attr pe;
-	struct membw_read_format return_value;
 	int fd;
 };
 
@@ -74,7 +73,7 @@ static void read_mem_bw_ioctl_perf_event_ioc_disable(int i)
  * @cas_count_cfg:	Config
  * @count:		iMC number
  */
-static void get_read_event_and_umask(char *cas_count_cfg, int count)
+static void get_read_event_and_umask(char *cas_count_cfg, unsigned int count)
 {
 	char *token[MAX_TOKENS];
 	int i = 0;
@@ -110,45 +109,114 @@ static int open_perf_read_event(int i, int cpu_no)
 	return 0;
 }
 
-/* Get type and config of an iMC counter's read event. */
-static int read_from_imc_dir(char *imc_dir, int count)
+static int parse_imc_read_bw_events(char *imc_dir, unsigned int type,
+				    unsigned int *count)
 {
-	char cas_count_cfg[1024], imc_counter_cfg[1024], imc_counter_type[1024];
+	char imc_events_dir[PATH_MAX], imc_counter_cfg[PATH_MAX];
+	unsigned int orig_count = *count;
+	char cas_count_cfg[1024];
+	struct dirent *ep;
+	int path_len;
+	int ret = -1;
+	int num_cfg;
 	FILE *fp;
+	DIR *dp;
+
+	path_len = snprintf(imc_events_dir, sizeof(imc_events_dir), "%sevents",
+			    imc_dir);
+	if (path_len >= sizeof(imc_events_dir)) {
+		ksft_print_msg("Unable to create path to %sevents\n", imc_dir);
+		return -1;
+	}
+
+	dp = opendir(imc_events_dir);
+	if (!dp) {
+		ksft_perror("Unable to open PMU events directory");
+		return -1;
+	}
+
+	while ((ep = readdir(dp))) {
+		/*
+		 * Parse all event files with READ_FILE_NAME prefix that
+		 * contain the event number and umask. Skip files containing
+		 * "." that contain unused properties of event.
+		 */
+		if (!strstr(ep->d_name, READ_FILE_NAME) ||
+		    strchr(ep->d_name, '.'))
+			continue;
+
+		path_len = snprintf(imc_counter_cfg, sizeof(imc_counter_cfg),
+				    "%s/%s", imc_events_dir, ep->d_name);
+		if (path_len >= sizeof(imc_counter_cfg)) {
+			ksft_print_msg("Unable to create path to %s/%s\n",
+				       imc_events_dir, ep->d_name);
+			goto out_close;
+		}
+		fp = fopen(imc_counter_cfg, "r");
+		if (!fp) {
+			ksft_perror("Failed to open iMC config file");
+			goto out_close;
+		}
+		num_cfg = fscanf(fp, "%1023s", cas_count_cfg);
+		fclose(fp);
+		if (num_cfg <= 0) {
+			ksft_perror("Could not get iMC cas count read");
+			goto out_close;
+		}
+		if (*count >= MAX_IMCS) {
+			ksft_print_msg("Maximum iMC count exceeded\n");
+			goto out_close;
+		}
+
+		imc_counters_config[*count].type = type;
+		get_read_event_and_umask(cas_count_cfg, *count);
+		/* Do not fail after incrementing *count. */
+		*count += 1;
+	}
+	if (*count == orig_count) {
+		ksft_print_msg("Unable to find events in %s\n", imc_events_dir);
+		goto out_close;
+	}
+	ret = 0;
+out_close:
+	closedir(dp);
+	return ret;
+}
+
+/* Get type and config of an iMC counter's read event. */
+static int read_from_imc_dir(char *imc_dir, unsigned int *count)
+{
+	char imc_counter_type[PATH_MAX];
+	unsigned int type;
+	int path_len;
+	FILE *fp;
+	int ret;
 
 	/* Get type of iMC counter */
-	sprintf(imc_counter_type, "%s%s", imc_dir, "type");
+	path_len = snprintf(imc_counter_type, sizeof(imc_counter_type),
+			    "%s%s", imc_dir, "type");
+	if (path_len >= sizeof(imc_counter_type)) {
+		ksft_print_msg("Unable to create path to %s%s\n",
+			       imc_dir, "type");
+		return -1;
+	}
 	fp = fopen(imc_counter_type, "r");
 	if (!fp) {
 		ksft_perror("Failed to open iMC counter type file");
 
 		return -1;
 	}
-	if (fscanf(fp, "%u", &imc_counters_config[count].type) <= 0) {
+	ret = fscanf(fp, "%u", &type);
+	fclose(fp);
+	if (ret <= 0) {
 		ksft_perror("Could not get iMC type");
-		fclose(fp);
-
 		return -1;
 	}
-	fclose(fp);
-
-	/* Get read config */
-	sprintf(imc_counter_cfg, "%s%s", imc_dir, READ_FILE_NAME);
-	fp = fopen(imc_counter_cfg, "r");
-	if (!fp) {
-		ksft_perror("Failed to open iMC config file");
-
-		return -1;
+	ret = parse_imc_read_bw_events(imc_dir, type, count);
+	if (ret) {
+		ksft_print_msg("Unable to parse bandwidth event and umask\n");
+		return ret;
 	}
-	if (fscanf(fp, "%1023s", cas_count_cfg) <= 0) {
-		ksft_perror("Could not get iMC cas count read");
-		fclose(fp);
-
-		return -1;
-	}
-	fclose(fp);
-
-	get_read_event_and_umask(cas_count_cfg, count);
 
 	return 0;
 }
@@ -197,13 +265,12 @@ static int num_of_imcs(void)
 			if (temp[0] >= '0' && temp[0] <= '9') {
 				sprintf(imc_dir, "%s/%s/", DYN_PMU_PATH,
 					ep->d_name);
-				ret = read_from_imc_dir(imc_dir, count);
+				ret = read_from_imc_dir(imc_dir, &count);
 				if (ret) {
 					closedir(dp);
 
 					return ret;
 				}
-				count++;
 			}
 		}
 		closedir(dp);
@@ -312,23 +379,23 @@ static int get_read_mem_bw_imc(float *bw_imc)
 	 * Take overflow into consideration before calculating total bandwidth.
 	 */
 	for (imc = 0; imc < imcs; imc++) {
+		struct membw_read_format measurement;
 		struct imc_counter_config *r =
 			&imc_counters_config[imc];
 
-		if (read(r->fd, &r->return_value,
-			 sizeof(struct membw_read_format)) == -1) {
+		if (read(r->fd, &measurement, sizeof(measurement)) == -1) {
 			ksft_perror("Couldn't get read bandwidth through iMC");
 			return -1;
 		}
 
-		__u64 r_time_enabled = r->return_value.time_enabled;
-		__u64 r_time_running = r->return_value.time_running;
+		__u64 r_time_enabled = measurement.time_enabled;
+		__u64 r_time_running = measurement.time_running;
 
 		if (r_time_enabled != r_time_running)
 			of_mul_read = (float)r_time_enabled /
 					(float)r_time_running;
 
-		reads += r->return_value.value * of_mul_read * SCALE;
+		reads += measurement.value * of_mul_read * SCALE;
 	}
 
 	*bw_imc = reads;
@@ -569,7 +636,7 @@ int resctrl_val(const struct resctrl_test *test,
 		goto reset_affinity;
 
 	if (param->init) {
-		ret = param->init(param, domain_id);
+		ret = param->init(test, uparams, param, domain_id);
 		if (ret)
 			goto reset_affinity;
 	}