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, 262 insertions, 0 deletions

diff --git a/tools/perf/bench/breakpoint.c b/tools/perf/bench/breakpoint.c
new file mode 100644
index 000000000..1b7cd4481
--- /dev/null
+++ b/tools/perf/bench/breakpoint.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <subcmd/parse-options.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/perf_event.h>
+#include <linux/time64.h>
+#include <sys/syscall.h>
+#include <sys/ioctl.h>
+#include <sys/time.h>
+#include <pthread.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include "bench.h"
+#include "futex.h"
+
+static struct {
+	unsigned int nbreakpoints;
+	unsigned int nparallel;
+	unsigned int nthreads;
+} thread_params = {
+	.nbreakpoints = 1,
+	.nparallel = 1,
+	.nthreads = 1,
+};
+
+static const struct option thread_options[] = {
+	OPT_UINTEGER('b', "breakpoints", &thread_params.nbreakpoints,
+		"Specify amount of breakpoints"),
+	OPT_UINTEGER('p', "parallelism", &thread_params.nparallel, "Specify amount of parallelism"),
+	OPT_UINTEGER('t', "threads", &thread_params.nthreads, "Specify amount of threads"),
+	OPT_END()
+};
+
+static const char * const thread_usage[] = {
+	"perf bench breakpoint thread <options>",
+	NULL
+};
+
+struct breakpoint {
+	int fd;
+	char watched;
+};
+
+static int breakpoint_setup(void *addr)
+{
+	struct perf_event_attr attr = { .size = 0, };
+	int fd;
+
+	attr.type = PERF_TYPE_BREAKPOINT;
+	attr.size = sizeof(attr);
+	attr.inherit = 1;
+	attr.exclude_kernel = 1;
+	attr.exclude_hv = 1;
+	attr.bp_addr = (unsigned long)addr;
+	attr.bp_type = HW_BREAKPOINT_RW;
+	attr.bp_len = HW_BREAKPOINT_LEN_1;
+	fd = syscall(SYS_perf_event_open, &attr, 0, -1, -1, 0);
+
+	if (fd < 0)
+		fd = -errno;
+
+	return fd;
+}
+
+static void *passive_thread(void *arg)
+{
+	unsigned int *done = (unsigned int *)arg;
+
+	while (!__atomic_load_n(done, __ATOMIC_RELAXED))
+		futex_wait(done, 0, NULL, 0);
+	return NULL;
+}
+
+static void *active_thread(void *arg)
+{
+	unsigned int *done = (unsigned int *)arg;
+
+	while (!__atomic_load_n(done, __ATOMIC_RELAXED));
+	return NULL;
+}
+
+static void *breakpoint_thread(void *arg)
+{
+	unsigned int i, done;
+	int *repeat = (int *)arg;
+	pthread_t *threads;
+
+	threads = calloc(thread_params.nthreads, sizeof(threads[0]));
+	if (!threads)
+		exit((perror("calloc"), EXIT_FAILURE));
+
+	while (__atomic_fetch_sub(repeat, 1, __ATOMIC_RELAXED) > 0) {
+		done = 0;
+		for (i = 0; i < thread_params.nthreads; i++) {
+			if (pthread_create(&threads[i], NULL, passive_thread, &done))
+				exit((perror("pthread_create"), EXIT_FAILURE));
+		}
+		__atomic_store_n(&done, 1, __ATOMIC_RELAXED);
+		futex_wake(&done, thread_params.nthreads, 0);
+		for (i = 0; i < thread_params.nthreads; i++)
+			pthread_join(threads[i], NULL);
+	}
+	free(threads);
+	return NULL;
+}
+
+// The benchmark creates nbreakpoints inheritable breakpoints,
+// then starts nparallel threads which create and join bench_repeat batches of nthreads threads.
+int bench_breakpoint_thread(int argc, const char **argv)
+{
+	unsigned int i, result_usec;
+	int repeat = bench_repeat;
+	struct breakpoint *breakpoints;
+	pthread_t *parallel;
+	struct timeval start, stop, diff;
+
+	if (parse_options(argc, argv, thread_options, thread_usage, 0)) {
+		usage_with_options(thread_usage, thread_options);
+		exit(EXIT_FAILURE);
+	}
+	breakpoints = calloc(thread_params.nbreakpoints, sizeof(breakpoints[0]));
+	parallel = calloc(thread_params.nparallel, sizeof(parallel[0]));
+	if (!breakpoints || !parallel)
+		exit((perror("calloc"), EXIT_FAILURE));
+
+	for (i = 0; i < thread_params.nbreakpoints; i++) {
+		breakpoints[i].fd = breakpoint_setup(&breakpoints[i].watched);
+
+		if (breakpoints[i].fd < 0) {
+			if (breakpoints[i].fd == -ENODEV) {
+				printf("Skipping perf bench breakpoint thread: No hardware support\n");
+				return 0;
+			}
+			exit((perror("perf_event_open"), EXIT_FAILURE));
+		}
+	}
+	gettimeofday(&start, NULL);
+	for (i = 0; i < thread_params.nparallel; i++) {
+		if (pthread_create(&parallel[i], NULL, breakpoint_thread, &repeat))
+			exit((perror("pthread_create"), EXIT_FAILURE));
+	}
+	for (i = 0; i < thread_params.nparallel; i++)
+		pthread_join(parallel[i], NULL);
+	gettimeofday(&stop, NULL);
+	timersub(&stop, &start, &diff);
+	for (i = 0; i < thread_params.nbreakpoints; i++)
+		close(breakpoints[i].fd);
+	free(parallel);
+	free(breakpoints);
+	switch (bench_format) {
+	case BENCH_FORMAT_DEFAULT:
+		printf("# Created/joined %d threads with %d breakpoints and %d parallelism\n",
+			bench_repeat, thread_params.nbreakpoints, thread_params.nparallel);
+		printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
+			(long)diff.tv_sec, (long)(diff.tv_usec / USEC_PER_MSEC));
+		result_usec = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
+		printf(" %14lf usecs/op\n",
+			(double)result_usec / bench_repeat / thread_params.nthreads);
+		printf(" %14lf usecs/op/cpu\n",
+			(double)result_usec / bench_repeat /
+			thread_params.nthreads * thread_params.nparallel);
+		break;
+	case BENCH_FORMAT_SIMPLE:
+		printf("%lu.%03lu\n", (long)diff.tv_sec, (long)(diff.tv_usec / USEC_PER_MSEC));
+		break;
+	default:
+		fprintf(stderr, "Unknown format: %d\n", bench_format);
+		exit(EXIT_FAILURE);
+	}
+	return 0;
+}
+
+static struct {
+	unsigned int npassive;
+	unsigned int nactive;
+} enable_params = {
+	.nactive = 0,
+	.npassive = 0,
+};
+
+static const struct option enable_options[] = {
+	OPT_UINTEGER('p', "passive", &enable_params.npassive, "Specify amount of passive threads"),
+	OPT_UINTEGER('a', "active", &enable_params.nactive, "Specify amount of active threads"),
+	OPT_END()
+};
+
+static const char * const enable_usage[] = {
+	"perf bench breakpoint enable <options>",
+	NULL
+};
+
+// The benchmark creates an inheritable breakpoint,
+// then starts npassive threads that block and nactive threads that actively spin
+// and then disables and enables the breakpoint bench_repeat times.
+int bench_breakpoint_enable(int argc, const char **argv)
+{
+	unsigned int i, nthreads, result_usec, done = 0;
+	char watched;
+	int fd;
+	pthread_t *threads;
+	struct timeval start, stop, diff;
+
+	if (parse_options(argc, argv, enable_options, enable_usage, 0)) {
+		usage_with_options(enable_usage, enable_options);
+		exit(EXIT_FAILURE);
+	}
+	fd = breakpoint_setup(&watched);
+
+	if (fd < 0) {
+		if (fd == -ENODEV) {
+			printf("Skipping perf bench breakpoint enable: No hardware support\n");
+			return 0;
+		}
+		exit((perror("perf_event_open"), EXIT_FAILURE));
+	}
+	nthreads = enable_params.npassive + enable_params.nactive;
+	threads = calloc(nthreads, sizeof(threads[0]));
+	if (!threads)
+		exit((perror("calloc"), EXIT_FAILURE));
+
+	for (i = 0; i < nthreads; i++) {
+		if (pthread_create(&threads[i], NULL,
+			i < enable_params.npassive ? passive_thread : active_thread, &done))
+			exit((perror("pthread_create"), EXIT_FAILURE));
+	}
+	usleep(10000);  // let the threads block
+	gettimeofday(&start, NULL);
+	for (i = 0; i < bench_repeat; i++) {
+		if (ioctl(fd, PERF_EVENT_IOC_DISABLE, 0))
+			exit((perror("ioctl(PERF_EVENT_IOC_DISABLE)"), EXIT_FAILURE));
+		if (ioctl(fd, PERF_EVENT_IOC_ENABLE, 0))
+			exit((perror("ioctl(PERF_EVENT_IOC_ENABLE)"), EXIT_FAILURE));
+	}
+	gettimeofday(&stop, NULL);
+	timersub(&stop, &start, &diff);
+	__atomic_store_n(&done, 1, __ATOMIC_RELAXED);
+	futex_wake(&done, enable_params.npassive, 0);
+	for (i = 0; i < nthreads; i++)
+		pthread_join(threads[i], NULL);
+	free(threads);
+	close(fd);
+	switch (bench_format) {
+	case BENCH_FORMAT_DEFAULT:
+		printf("# Enabled/disabled breakpoint %d time with %d passive and %d active threads\n",
+			bench_repeat, enable_params.npassive, enable_params.nactive);
+		printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
+			(long)diff.tv_sec, (long)(diff.tv_usec / USEC_PER_MSEC));
+		result_usec = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
+		printf(" %14lf usecs/op\n", (double)result_usec / bench_repeat);
+		break;
+	case BENCH_FORMAT_SIMPLE:
+		printf("%lu.%03lu\n", (long)diff.tv_sec, (long)(diff.tv_usec / USEC_PER_MSEC));
+		break;
+	default:
+		fprintf(stderr, "Unknown format: %d\n", bench_format);
+		exit(EXIT_FAILURE);
+	}
+	return 0;
+}