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-rw-r--r--tools/perf/bench/breakpoint.c262
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 0000000000..dfd18f5db9
--- /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"
+
+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;
+}