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

Author: torvalds

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;
 	}
 
@@ -132,23 +125,23 @@ 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 */
 	ret = ioctl(pe_fd, PERF_EVENT_IOC_DISABLE, 0);
 	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);
-
-		avg_diff = delta / *prev_avg_llc_val;
-		ret = platform && (avg_diff * 100) < (float)min_diff_percent;
+		ret = platform && (avg_llc_val < *prev_avg_llc_val);
 
-		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);
 
 /*