diff options
Diffstat (limited to 'tools/perf')
| -rw-r--r-- | tools/perf/util/evsel.c | 79 |
1 files changed, 78 insertions, 1 deletions
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 697428efa644..bc144388f892 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -3581,6 +3581,78 @@ static bool find_process(const char *name) return ret ? false : true; } +static int dump_perf_event_processes(char *msg, size_t size) +{ + DIR *proc_dir; + struct dirent *proc_entry; + int printed = 0; + + proc_dir = opendir(procfs__mountpoint()); + if (!proc_dir) + return 0; + + /* Walk through the /proc directory. */ + while ((proc_entry = readdir(proc_dir)) != NULL) { + char buf[256]; + DIR *fd_dir; + struct dirent *fd_entry; + int fd_dir_fd; + + if (proc_entry->d_type != DT_DIR || + !isdigit(proc_entry->d_name[0]) || + strlen(proc_entry->d_name) > sizeof(buf) - 4) + continue; + + scnprintf(buf, sizeof(buf), "%s/fd", proc_entry->d_name); + fd_dir_fd = openat(dirfd(proc_dir), buf, O_DIRECTORY); + if (fd_dir_fd == -1) + continue; + fd_dir = fdopendir(fd_dir_fd); + if (!fd_dir) { + close(fd_dir_fd); + continue; + } + while ((fd_entry = readdir(fd_dir)) != NULL) { + ssize_t link_size; + + if (fd_entry->d_type != DT_LNK) + continue; + link_size = readlinkat(fd_dir_fd, fd_entry->d_name, buf, sizeof(buf)); + if (link_size < 0) + continue; + /* Take care as readlink doesn't null terminate the string. */ + if (!strncmp(buf, "anon_inode:[perf_event]", link_size)) { + int cmdline_fd; + ssize_t cmdline_size; + + scnprintf(buf, sizeof(buf), "%s/cmdline", proc_entry->d_name); + cmdline_fd = openat(dirfd(proc_dir), buf, O_RDONLY); + if (cmdline_fd == -1) + continue; + cmdline_size = read(cmdline_fd, buf, sizeof(buf) - 1); + close(cmdline_fd); + if (cmdline_size < 0) + continue; + buf[cmdline_size] = '\0'; + for (ssize_t i = 0; i < cmdline_size; i++) { + if (buf[i] == '\0') + buf[i] = ' '; + } + + if (printed == 0) + printed += scnprintf(msg, size, "Possible processes:\n"); + + printed += scnprintf(msg + printed, size - printed, + "%s %s\n", proc_entry->d_name, buf); + break; + } + } + closedir(fd_dir); + } + closedir(proc_dir); + return printed; +} + int __weak arch_evsel__open_strerror(struct evsel *evsel __maybe_unused, char *msg __maybe_unused, size_t size __maybe_unused) @@ -3614,7 +3686,7 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target, printed += scnprintf(msg, size, "No permission to enable %s event.\n\n", evsel__name(evsel)); - return scnprintf(msg + printed, size - printed, + return printed + scnprintf(msg + printed, size - printed, "Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open\n" "access to performance monitoring and observability operations for processes\n" "without CAP_PERFMON, CAP_SYS_PTRACE or CAP_SYS_ADMIN Linux capability.\n" @@ -3681,6 +3753,11 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target, return scnprintf(msg, size, "The PMU counters are busy/taken by another profiler.\n" "We found oprofile daemon running, please stop it and try again."); + printed += scnprintf( + msg, size, + "The PMU %s counters are busy and in use by another process.\n", + evsel->pmu ? evsel->pmu->name : ""); + return printed + dump_perf_event_processes(msg + printed, size - printed); break; case EINVAL: if (evsel->core.attr.sample_type & PERF_SAMPLE_CODE_PAGE_SIZE && perf_missing_features.code_page_size) |