1// SPDX-License-Identifier: GPL-2.0
  2
  3#include <subcmd/parse-options.h>
  4#include <linux/hw_breakpoint.h>
  5#include <linux/perf_event.h>
  6#include <linux/time64.h>
  7#include <sys/syscall.h>
  8#include <sys/ioctl.h>
  9#include <sys/time.h>
 10#include <pthread.h>
 11#include <stddef.h>
 12#include <stdlib.h>
 13#include <unistd.h>
 14#include <stdio.h>
 15#include <errno.h>
 16#include "bench.h"
 17#include "futex.h"
 18
 19struct {
 20	unsigned int nbreakpoints;
 21	unsigned int nparallel;
 22	unsigned int nthreads;
 23} thread_params = {
 24	.nbreakpoints = 1,
 25	.nparallel = 1,
 26	.nthreads = 1,
 27};
 28
 29static const struct option thread_options[] = {
 30	OPT_UINTEGER('b', "breakpoints", &thread_params.nbreakpoints,
 31		"Specify amount of breakpoints"),
 32	OPT_UINTEGER('p', "parallelism", &thread_params.nparallel, "Specify amount of parallelism"),
 33	OPT_UINTEGER('t', "threads", &thread_params.nthreads, "Specify amount of threads"),
 34	OPT_END()
 35};
 36
 37static const char * const thread_usage[] = {
 38	"perf bench breakpoint thread <options>",
 39	NULL
 40};
 41
 42struct breakpoint {
 43	int fd;
 44	char watched;
 45};
 46
 47static int breakpoint_setup(void *addr)
 48{
 49	struct perf_event_attr attr = { .size = 0, };
 50
 51	attr.type = PERF_TYPE_BREAKPOINT;
 52	attr.size = sizeof(attr);
 53	attr.inherit = 1;
 54	attr.exclude_kernel = 1;
 55	attr.exclude_hv = 1;
 56	attr.bp_addr = (unsigned long)addr;
 57	attr.bp_type = HW_BREAKPOINT_RW;
 58	attr.bp_len = HW_BREAKPOINT_LEN_1;
 59	return syscall(SYS_perf_event_open, &attr, 0, -1, -1, 0);
 60}
 61
 62static void *passive_thread(void *arg)
 63{
 64	unsigned int *done = (unsigned int *)arg;
 65
 66	while (!__atomic_load_n(done, __ATOMIC_RELAXED))
 67		futex_wait(done, 0, NULL, 0);
 68	return NULL;
 69}
 70
 71static void *active_thread(void *arg)
 72{
 73	unsigned int *done = (unsigned int *)arg;
 74
 75	while (!__atomic_load_n(done, __ATOMIC_RELAXED));
 76	return NULL;
 77}
 78
 79static void *breakpoint_thread(void *arg)
 80{
 81	unsigned int i, done;
 82	int *repeat = (int *)arg;
 83	pthread_t *threads;
 84
 85	threads = calloc(thread_params.nthreads, sizeof(threads[0]));
 86	if (!threads)
 87		exit((perror("calloc"), EXIT_FAILURE));
 88
 89	while (__atomic_fetch_sub(repeat, 1, __ATOMIC_RELAXED) > 0) {
 90		done = 0;
 91		for (i = 0; i < thread_params.nthreads; i++) {
 92			if (pthread_create(&threads[i], NULL, passive_thread, &done))
 93				exit((perror("pthread_create"), EXIT_FAILURE));
 94		}
 95		__atomic_store_n(&done, 1, __ATOMIC_RELAXED);
 96		futex_wake(&done, thread_params.nthreads, 0);
 97		for (i = 0; i < thread_params.nthreads; i++)
 98			pthread_join(threads[i], NULL);
 99	}
100	free(threads);
101	return NULL;
102}
103
104// The benchmark creates nbreakpoints inheritable breakpoints,
105// then starts nparallel threads which create and join bench_repeat batches of nthreads threads.
106int bench_breakpoint_thread(int argc, const char **argv)
107{
108	unsigned int i, result_usec;
109	int repeat = bench_repeat;
110	struct breakpoint *breakpoints;
111	pthread_t *parallel;
112	struct timeval start, stop, diff;
113
114	if (parse_options(argc, argv, thread_options, thread_usage, 0)) {
115		usage_with_options(thread_usage, thread_options);
116		exit(EXIT_FAILURE);
117	}
118	breakpoints = calloc(thread_params.nbreakpoints, sizeof(breakpoints[0]));
119	parallel = calloc(thread_params.nparallel, sizeof(parallel[0]));
120	if (!breakpoints || !parallel)
121		exit((perror("calloc"), EXIT_FAILURE));
122
123	for (i = 0; i < thread_params.nbreakpoints; i++) {
124		breakpoints[i].fd = breakpoint_setup(&breakpoints[i].watched);
125		if (breakpoints[i].fd == -1)
126			exit((perror("perf_event_open"), EXIT_FAILURE));
127	}
128	gettimeofday(&start, NULL);
129	for (i = 0; i < thread_params.nparallel; i++) {
130		if (pthread_create(&parallel[i], NULL, breakpoint_thread, &repeat))
131			exit((perror("pthread_create"), EXIT_FAILURE));
132	}
133	for (i = 0; i < thread_params.nparallel; i++)
134		pthread_join(parallel[i], NULL);
135	gettimeofday(&stop, NULL);
136	timersub(&stop, &start, &diff);
137	for (i = 0; i < thread_params.nbreakpoints; i++)
138		close(breakpoints[i].fd);
139	free(parallel);
140	free(breakpoints);
141	switch (bench_format) {
142	case BENCH_FORMAT_DEFAULT:
143		printf("# Created/joined %d threads with %d breakpoints and %d parallelism\n",
144			bench_repeat, thread_params.nbreakpoints, thread_params.nparallel);
145		printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
146			(long)diff.tv_sec, (long)(diff.tv_usec / USEC_PER_MSEC));
147		result_usec = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
148		printf(" %14lf usecs/op\n",
149			(double)result_usec / bench_repeat / thread_params.nthreads);
150		printf(" %14lf usecs/op/cpu\n",
151			(double)result_usec / bench_repeat /
152			thread_params.nthreads * thread_params.nparallel);
153		break;
154	case BENCH_FORMAT_SIMPLE:
155		printf("%lu.%03lu\n", (long)diff.tv_sec, (long)(diff.tv_usec / USEC_PER_MSEC));
156		break;
157	default:
158		fprintf(stderr, "Unknown format: %d\n", bench_format);
159		exit(EXIT_FAILURE);
160	}
161	return 0;
162}
163
164struct {
165	unsigned int npassive;
166	unsigned int nactive;
167} enable_params = {
168	.nactive = 0,
169	.npassive = 0,
170};
171
172static const struct option enable_options[] = {
173	OPT_UINTEGER('p', "passive", &enable_params.npassive, "Specify amount of passive threads"),
174	OPT_UINTEGER('a', "active", &enable_params.nactive, "Specify amount of active threads"),
175	OPT_END()
176};
177
178static const char * const enable_usage[] = {
179	"perf bench breakpoint enable <options>",
180	NULL
181};
182
183// The benchmark creates an inheritable breakpoint,
184// then starts npassive threads that block and nactive threads that actively spin
185// and then disables and enables the breakpoint bench_repeat times.
186int bench_breakpoint_enable(int argc, const char **argv)
187{
188	unsigned int i, nthreads, result_usec, done = 0;
189	char watched;
190	int fd;
191	pthread_t *threads;
192	struct timeval start, stop, diff;
193
194	if (parse_options(argc, argv, enable_options, enable_usage, 0)) {
195		usage_with_options(enable_usage, enable_options);
196		exit(EXIT_FAILURE);
197	}
198	fd = breakpoint_setup(&watched);
199	if (fd == -1)
200		exit((perror("perf_event_open"), EXIT_FAILURE));
201	nthreads = enable_params.npassive + enable_params.nactive;
202	threads = calloc(nthreads, sizeof(threads[0]));
203	if (!threads)
204		exit((perror("calloc"), EXIT_FAILURE));
205
206	for (i = 0; i < nthreads; i++) {
207		if (pthread_create(&threads[i], NULL,
208			i < enable_params.npassive ? passive_thread : active_thread, &done))
209			exit((perror("pthread_create"), EXIT_FAILURE));
210	}
211	usleep(10000);  // let the threads block
212	gettimeofday(&start, NULL);
213	for (i = 0; i < bench_repeat; i++) {
214		if (ioctl(fd, PERF_EVENT_IOC_DISABLE, 0))
215			exit((perror("ioctl(PERF_EVENT_IOC_DISABLE)"), EXIT_FAILURE));
216		if (ioctl(fd, PERF_EVENT_IOC_ENABLE, 0))
217			exit((perror("ioctl(PERF_EVENT_IOC_ENABLE)"), EXIT_FAILURE));
218	}
219	gettimeofday(&stop, NULL);
220	timersub(&stop, &start, &diff);
221	__atomic_store_n(&done, 1, __ATOMIC_RELAXED);
222	futex_wake(&done, enable_params.npassive, 0);
223	for (i = 0; i < nthreads; i++)
224		pthread_join(threads[i], NULL);
225	free(threads);
226	close(fd);
227	switch (bench_format) {
228	case BENCH_FORMAT_DEFAULT:
229		printf("# Enabled/disabled breakpoint %d time with %d passive and %d active threads\n",
230			bench_repeat, enable_params.npassive, enable_params.nactive);
231		printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
232			(long)diff.tv_sec, (long)(diff.tv_usec / USEC_PER_MSEC));
233		result_usec = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
234		printf(" %14lf usecs/op\n", (double)result_usec / bench_repeat);
235		break;
236	case BENCH_FORMAT_SIMPLE:
237		printf("%lu.%03lu\n", (long)diff.tv_sec, (long)(diff.tv_usec / USEC_PER_MSEC));
238		break;
239	default:
240		fprintf(stderr, "Unknown format: %d\n", bench_format);
241		exit(EXIT_FAILURE);
242	}
243	return 0;
244}