* it overloads any global configuration.
*/
apply_config_terms(evsel, opts);
+
+ evsel->ignore_missing_thread = opts->ignore_missing_thread;
}
static int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
return fprintf(fp, " %-32s %s\n", name, val);
}
-static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
- struct thread_map *threads)
+static bool ignore_missing_thread(struct perf_evsel *evsel,
+ struct thread_map *threads,
+ int thread, int err)
+{
+ if (!evsel->ignore_missing_thread)
+ return false;
+
+ /* The system wide setup does not work with threads. */
+ if (evsel->system_wide)
+ return false;
+
+ /* The -ESRCH is perf event syscall errno for pid's not found. */
+ if (err != -ESRCH)
+ return false;
+
+ /* If there's only one thread, let it fail. */
+ if (threads->nr == 1)
+ return false;
+
+ if (thread_map__remove(threads, thread))
+ return false;
+
+ pr_warning("WARNING: Ignored open failure for pid %d\n",
+ thread_map__pid(threads, thread));
+ return true;
+}
+
+int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
+ struct thread_map *threads)
{
int cpu, thread, nthreads;
unsigned long flags = PERF_FLAG_FD_CLOEXEC;
if (perf_missing_features.write_backward && evsel->attr.write_backward)
return -EINVAL;
+ if (cpus == NULL) {
+ static struct cpu_map *empty_cpu_map;
+
+ if (empty_cpu_map == NULL) {
+ empty_cpu_map = cpu_map__dummy_new();
+ if (empty_cpu_map == NULL)
+ return -ENOMEM;
+ }
+
+ cpus = empty_cpu_map;
+ }
+
+ if (threads == NULL) {
+ static struct thread_map *empty_thread_map;
+
+ if (empty_thread_map == NULL) {
+ empty_thread_map = thread_map__new_by_tid(-1);
+ if (empty_thread_map == NULL)
+ return -ENOMEM;
+ }
+
+ threads = empty_thread_map;
+ }
+
if (evsel->system_wide)
nthreads = 1;
else
for (cpu = 0; cpu < cpus->nr; cpu++) {
for (thread = 0; thread < nthreads; thread++) {
- int group_fd;
+ int fd, group_fd;
if (!evsel->cgrp && !evsel->system_wide)
pid = thread_map__pid(threads, thread);
pr_debug2("sys_perf_event_open: pid %d cpu %d group_fd %d flags %#lx",
pid, cpus->map[cpu], group_fd, flags);
- FD(evsel, cpu, thread) = sys_perf_event_open(&evsel->attr,
- pid,
- cpus->map[cpu],
- group_fd, flags);
- if (FD(evsel, cpu, thread) < 0) {
+ fd = sys_perf_event_open(&evsel->attr, pid, cpus->map[cpu],
+ group_fd, flags);
+
+ FD(evsel, cpu, thread) = fd;
+
+ if (fd < 0) {
err = -errno;
+
+ if (ignore_missing_thread(evsel, threads, thread, err)) {
+ /*
+ * We just removed 1 thread, so take a step
+ * back on thread index and lower the upper
+ * nthreads limit.
+ */
+ nthreads--;
+ thread--;
+
+ /* ... and pretend like nothing have happened. */
+ err = 0;
+ continue;
+ }
+
pr_debug2("\nsys_perf_event_open failed, error %d\n",
err);
goto try_fallback;
}
- pr_debug2(" = %d\n", FD(evsel, cpu, thread));
+ pr_debug2(" = %d\n", fd);
if (evsel->bpf_fd >= 0) {
- int evt_fd = FD(evsel, cpu, thread);
+ int evt_fd = fd;
int bpf_fd = evsel->bpf_fd;
err = ioctl(evt_fd,
perf_evsel__free_fd(evsel);
}
-static struct {
- struct cpu_map map;
- int cpus[1];
-} empty_cpu_map = {
- .map.nr = 1,
- .cpus = { -1, },
-};
-
-static struct {
- struct thread_map map;
- int threads[1];
-} empty_thread_map = {
- .map.nr = 1,
- .threads = { -1, },
-};
-
-int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
- struct thread_map *threads)
-{
- if (cpus == NULL) {
- /* Work around old compiler warnings about strict aliasing */
- cpus = &empty_cpu_map.map;
- }
-
- if (threads == NULL)
- threads = &empty_thread_map.map;
-
- return __perf_evsel__open(evsel, cpus, threads);
-}
-
int perf_evsel__open_per_cpu(struct perf_evsel *evsel,
struct cpu_map *cpus)
{
- return __perf_evsel__open(evsel, cpus, &empty_thread_map.map);
+ return perf_evsel__open(evsel, cpus, NULL);
}
int perf_evsel__open_per_thread(struct perf_evsel *evsel,
struct thread_map *threads)
{
- return __perf_evsel__open(evsel, &empty_cpu_map.map, threads);
+ return perf_evsel__open(evsel, NULL, threads);
}
static int perf_evsel__parse_id_sample(const struct perf_evsel *evsel,
" -1: Allow use of (almost) all events by all users\n"
">= 0: Disallow raw tracepoint access by users without CAP_IOC_LOCK\n"
">= 1: Disallow CPU event access by users without CAP_SYS_ADMIN\n"
- ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN",
+ ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN\n\n"
+ "To make this setting permanent, edit /etc/sysctl.conf too, e.g.:\n\n"
+ " kernel.perf_event_paranoid = -1\n" ,
target->system_wide ? "system-wide " : "",
perf_event_paranoid());
case ENOENT:
projects / linux.git / blobdiff