diff options
| -rw-r--r-- | tools/perf/builtin-record.c | 109 |
1 files changed, 71 insertions, 38 deletions
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 65301c5ca1de..9b7c6d887d5a 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -402,7 +402,7 @@ static void atexit_header(void) perf_header__write(&session->header, output, true); } -static int __cmd_record(int argc, const char **argv) +static int __cmd_record(int argc __used, const char **argv) { int i, counter; struct stat st; @@ -410,6 +410,8 @@ static int __cmd_record(int argc, const char **argv) int flags; int err; unsigned long waking = 0; + int child_ready_pipe[2], go_pipe[2]; + char buf; page_size = sysconf(_SC_PAGE_SIZE); nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); @@ -420,6 +422,11 @@ static int __cmd_record(int argc, const char **argv) signal(SIGCHLD, sig_handler); signal(SIGINT, sig_handler); + if (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0) { + perror("failed to create pipes"); + exit(-1); + } + if (!stat(output_name, &st) && st.st_size) { if (!force) { if (!append_file) { @@ -476,19 +483,65 @@ static int __cmd_record(int argc, const char **argv) atexit(atexit_header); - if (!system_wide) { - pid = target_pid; - if (pid == -1) - pid = getpid(); + if (target_pid == -1) { + pid = fork(); + if (pid < 0) { + perror("failed to fork"); + exit(-1); + } - open_counters(profile_cpu, pid); - } else { - if (profile_cpu != -1) { - open_counters(profile_cpu, target_pid); - } else { - for (i = 0; i < nr_cpus; i++) - open_counters(i, target_pid); + if (!pid) { + close(child_ready_pipe[0]); + close(go_pipe[1]); + fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC); + + /* + * Do a dummy execvp to get the PLT entry resolved, + * so we avoid the resolver overhead on the real + * execvp call. + */ + execvp("", (char **)argv); + + /* + * Tell the parent we're ready to go + */ + close(child_ready_pipe[1]); + + /* + * Wait until the parent tells us to go. + */ + if (read(go_pipe[0], &buf, 1) == -1) + perror("unable to read pipe"); + + execvp(argv[0], (char **)argv); + + perror(argv[0]); + exit(-1); } + + child_pid = pid; + + if (!system_wide) + target_pid = pid; + + close(child_ready_pipe[1]); + close(go_pipe[0]); + /* + * wait for child to settle + */ + if (read(child_ready_pipe[0], &buf, 1) == -1) { + perror("unable to read pipe"); + exit(-1); + } + close(child_ready_pipe[0]); + } + + + if (!system_wide || profile_cpu != -1) { + open_counters(profile_cpu, target_pid); + } else { + for (i = 0; i < nr_cpus; i++) + open_counters(i, target_pid); } if (file_new) { @@ -503,31 +556,6 @@ static int __cmd_record(int argc, const char **argv) else event__synthesize_threads(process_synthesized_event, session); - if (target_pid == -1 && argc) { - pid = fork(); - if (pid < 0) - die("failed to fork"); - - if (!pid) { - if (execvp(argv[0], (char **)argv)) { - perror(argv[0]); - exit(-1); - } - } else { - /* - * Wait a bit for the execv'ed child to appear - * and be updated in /proc - * FIXME: Do you know a less heuristical solution? - */ - usleep(1000); - event__synthesize_thread(pid, - process_synthesized_event, - session); - } - - child_pid = pid; - } - if (realtime_prio) { struct sched_param param; @@ -538,6 +566,11 @@ static int __cmd_record(int argc, const char **argv) } } + /* + * Let the child rip + */ + close(go_pipe[1]); + for (;;) { int hits = samples; @@ -634,7 +667,7 @@ int cmd_record(int argc, const char **argv, const char *prefix __used) argc = parse_options(argc, argv, options, record_usage, PARSE_OPT_STOP_AT_NON_OPTION); - if (!argc && target_pid == -1 && !system_wide) + if (!argc && target_pid == -1 && (!system_wide || profile_cpu == -1)) usage_with_options(record_usage, options); symbol__init(); |