tools/perf/bench/breakpoint.c - linux - Git at Google

 // 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"

 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;
 }

 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;
 }
	// 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"

	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;
	}

	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;
	}