scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 234 insertions, 0 deletions

diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c
new file mode 100644
index 000000000..9283f4784
--- /dev/null
+++ b/samples/bpf/sampleip_user.c
@@ -0,0 +1,234 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sampleip: sample instruction pointer and frequency count in a BPF map.
+ *
+ * Copyright 2016 Netflix, Inc.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <linux/perf_event.h>
+#include <linux/ptrace.h>
+#include <linux/bpf.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+#include "perf-sys.h"
+#include "trace_helpers.h"
+
+#define DEFAULT_FREQ	99
+#define DEFAULT_SECS	5
+#define MAX_IPS		8192
+
+static int map_fd;
+static int nr_cpus;
+static long _text_addr;
+
+static void usage(void)
+{
+	printf("USAGE: sampleip [-F freq] [duration]\n");
+	printf("       -F freq    # sample frequency (Hertz), default 99\n");
+	printf("       duration   # sampling duration (seconds), default 5\n");
+}
+
+static int sampling_start(int freq, struct bpf_program *prog,
+			  struct bpf_link *links[])
+{
+	int i, pmu_fd;
+
+	struct perf_event_attr pe_sample_attr = {
+		.type = PERF_TYPE_SOFTWARE,
+		.freq = 1,
+		.sample_period = freq,
+		.config = PERF_COUNT_SW_CPU_CLOCK,
+		.inherit = 1,
+	};
+
+	for (i = 0; i < nr_cpus; i++) {
+		pmu_fd = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i,
+					    -1 /* group_fd */, 0 /* flags */);
+		if (pmu_fd < 0) {
+			fprintf(stderr, "ERROR: Initializing perf sampling\n");
+			return 1;
+		}
+		links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
+		if (libbpf_get_error(links[i])) {
+			fprintf(stderr, "ERROR: Attach perf event\n");
+			links[i] = NULL;
+			close(pmu_fd);
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+static void sampling_end(struct bpf_link *links[])
+{
+	int i;
+
+	for (i = 0; i < nr_cpus; i++)
+		bpf_link__destroy(links[i]);
+}
+
+struct ipcount {
+	__u64 ip;
+	__u32 count;
+};
+
+/* used for sorting */
+struct ipcount counts[MAX_IPS];
+
+static int count_cmp(const void *p1, const void *p2)
+{
+	return ((struct ipcount *)p1)->count - ((struct ipcount *)p2)->count;
+}
+
+static void print_ip_map(int fd)
+{
+	struct ksym *sym;
+	__u64 key, next_key;
+	__u32 value;
+	int i, max;
+
+	printf("%-19s %-32s %s\n", "ADDR", "KSYM", "COUNT");
+
+	/* fetch IPs and counts */
+	key = 0, i = 0;
+	while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
+		bpf_map_lookup_elem(fd, &next_key, &value);
+		counts[i].ip = next_key;
+		counts[i++].count = value;
+		key = next_key;
+	}
+	max = i;
+
+	/* sort and print */
+	qsort(counts, max, sizeof(struct ipcount), count_cmp);
+	for (i = 0; i < max; i++) {
+		if (counts[i].ip > _text_addr) {
+			sym = ksym_search(counts[i].ip);
+			if (!sym) {
+				printf("ksym not found. Is kallsyms loaded?\n");
+				continue;
+			}
+
+			printf("0x%-17llx %-32s %u\n", counts[i].ip, sym->name,
+			       counts[i].count);
+		} else {
+			printf("0x%-17llx %-32s %u\n", counts[i].ip, "(user)",
+			       counts[i].count);
+		}
+	}
+
+	if (max == MAX_IPS) {
+		printf("WARNING: IP hash was full (max %d entries); ", max);
+		printf("may have dropped samples\n");
+	}
+}
+
+static void int_exit(int sig)
+{
+	printf("\n");
+	print_ip_map(map_fd);
+	exit(0);
+}
+
+int main(int argc, char **argv)
+{
+	int opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS, error = 1;
+	struct bpf_object *obj = NULL;
+	struct bpf_program *prog;
+	struct bpf_link **links;
+	char filename[256];
+
+	/* process arguments */
+	while ((opt = getopt(argc, argv, "F:h")) != -1) {
+		switch (opt) {
+		case 'F':
+			freq = atoi(optarg);
+			break;
+		case 'h':
+		default:
+			usage();
+			return 0;
+		}
+	}
+	if (argc - optind == 1)
+		secs = atoi(argv[optind]);
+	if (freq == 0 || secs == 0) {
+		usage();
+		return 1;
+	}
+
+	/* initialize kernel symbol translation */
+	if (load_kallsyms()) {
+		fprintf(stderr, "ERROR: loading /proc/kallsyms\n");
+		return 2;
+	}
+
+	/* used to determine whether the address is kernel space */
+	_text_addr = ksym_get_addr("_text");
+	if (!_text_addr) {
+		fprintf(stderr, "ERROR: no '_text' in /proc/kallsyms\n");
+		return 3;
+	}
+
+	/* create perf FDs for each CPU */
+	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+	links = calloc(nr_cpus, sizeof(struct bpf_link *));
+	if (!links) {
+		fprintf(stderr, "ERROR: malloc of links\n");
+		goto cleanup;
+	}
+
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		obj = NULL;
+		goto cleanup;
+	}
+
+	prog = bpf_object__find_program_by_name(obj, "do_sample");
+	if (!prog) {
+		fprintf(stderr, "ERROR: finding a prog in obj file failed\n");
+		goto cleanup;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map");
+	if (map_fd < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	signal(SIGINT, int_exit);
+	signal(SIGTERM, int_exit);
+
+	/* do sampling */
+	printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",
+	       freq, secs);
+	if (sampling_start(freq, prog, links) != 0)
+		goto cleanup;
+
+	sleep(secs);
+	error = 0;
+
+cleanup:
+	sampling_end(links);
+	/* output sample counts */
+	if (!error)
+		print_ip_map(map_fd);
+
+	free(links);
+	bpf_object__close(obj);
+	return error;
+}