[PATCH v2 2/3] perf script: Print comm, fork and exit events also

From: Namhyung Kim
Date: Mon Nov 18 2013 - 00:35:34 EST


If --show-task option is given, also print internal COMM, FORK and
EXIT events. It would be helpful for debugging.

$ perf script --show-task
...
swapper 0 [009] 3350640.335261: sched:sched_switch: prev_comm=swapper/9
sleep 9486 [009] 3350640.335509: comm: perf --> sleep (9486)
sleep 9486 [009] 3350640.335806: sched:sched_stat_runtime: comm=sleep pid=9486
firefox 2635 [003] 3350641.275896: fork: firefox (2635 --> 9487)
firefox 2635 [003] 3350641.275896: sched:sched_process_fork: comm=firefox pid=2635
sleep 9486 [009] 3350641.336009: exit: sleep (9486)

Suggested-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/Documentation/perf-script.txt | 3 +
tools/perf/builtin-script.c | 115 +++++++++++++++++++++++++++++++
2 files changed, 118 insertions(+)

diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index e9cbfcddfa3f..9a9a7c3d592d 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -203,6 +203,9 @@ OPTIONS
--show-kernel-path::
Try to resolve the path of [kernel.kallsyms]

+--show-task
+ Display task related events (e.g. FORK, COMM, EXIT).
+
SEE ALSO
--------
linkperf:perf-record[1], linkperf:perf-script-perl[1],
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index b392770766dd..d05e6d835877 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -548,6 +548,7 @@ static int process_sample_event(struct perf_tool *tool __maybe_unused,
struct perf_script {
struct perf_tool tool;
struct perf_session *session;
+ bool show_task_events;
};

static int process_attr(struct perf_tool *tool, union perf_event *event,
@@ -578,6 +579,111 @@ static int process_attr(struct perf_tool *tool, union perf_event *event,
return perf_evsel__check_attr(evsel, scr->session);
}

+static int process_comm_event(struct perf_tool *tool,
+ union perf_event *event,
+ struct perf_sample *sample,
+ struct machine *machine)
+{
+ struct thread *thread;
+ struct perf_script *script = container_of(tool, struct perf_script, tool);
+ struct perf_session *session = script->session;
+ struct perf_evsel *evsel = perf_evlist__first(session->evlist);
+ char *oldname;
+ int ret = -1;
+
+ thread = machine__findnew_thread(machine, event->comm.pid, event->comm.tid);
+ if (thread == NULL) {
+ pr_debug("problem processing COMM event, skipping it.\n");
+ return -1;
+ }
+
+ oldname = strdup(thread__comm_str(thread));
+ if (oldname == NULL) {
+ pr_debug("problem processing COMM event, skipping it.\n");
+ return -1;
+ }
+
+ if (perf_event__process_comm(tool, event, sample, machine) < 0)
+ goto out;
+
+ if (!evsel->attr.sample_id_all) {
+ sample->cpu = 0;
+ sample->time = 0;
+ sample->tid = event->comm.tid;
+ sample->pid = event->comm.pid;
+ }
+ print_sample_start(sample, thread, evsel);
+ printf("comm: %s --> %s (%d)\n", oldname, event->comm.comm,
+ event->comm.tid);
+ ret = 0;
+
+out:
+ free(oldname);
+ return ret;
+}
+
+static int process_fork_event(struct perf_tool *tool,
+ union perf_event *event,
+ struct perf_sample *sample,
+ struct machine *machine)
+{
+ struct thread *thread;
+ struct perf_script *script = container_of(tool, struct perf_script, tool);
+ struct perf_session *session = script->session;
+ struct perf_evsel *evsel = perf_evlist__first(session->evlist);
+
+ if (perf_event__process_fork(tool, event, sample, machine) < 0)
+ return -1;
+
+ thread = machine__findnew_thread(machine, event->fork.pid, event->fork.tid);
+ if (thread == NULL) {
+ pr_debug("problem processing FORK event, skipping it.\n");
+ return -1;
+ }
+
+ if (!evsel->attr.sample_id_all) {
+ sample->cpu = 0;
+ sample->time = event->fork.time;
+ sample->tid = event->fork.tid;
+ sample->pid = event->fork.pid;
+ }
+ print_sample_start(sample, thread, evsel);
+ printf("fork: %s (%d --> %d)\n", thread__comm_str(thread),
+ event->fork.ptid, event->fork.tid);
+
+ return 0;
+}
+static int process_exit_event(struct perf_tool *tool,
+ union perf_event *event,
+ struct perf_sample *sample,
+ struct machine *machine)
+{
+ struct thread *thread;
+ struct perf_script *script = container_of(tool, struct perf_script, tool);
+ struct perf_session *session = script->session;
+ struct perf_evsel *evsel = perf_evlist__first(session->evlist);
+
+ thread = machine__findnew_thread(machine, event->fork.pid, event->fork.tid);
+ if (thread == NULL) {
+ pr_debug("problem processing EXIT event, skipping it.\n");
+ return -1;
+ }
+
+ if (!evsel->attr.sample_id_all) {
+ sample->cpu = 0;
+ sample->time = 0;
+ sample->tid = event->comm.tid;
+ sample->pid = event->comm.pid;
+ }
+ print_sample_start(sample, thread, evsel);
+ printf("exit: %s (%d)\n", thread__comm_str(thread), event->fork.tid);
+
+ if (perf_event__process_exit(tool, event, sample, machine) < 0)
+ return -1;
+
+ return 0;
+}
+
static void sig_handler(int sig __maybe_unused)
{
session_done = 1;
@@ -589,6 +695,13 @@ static int __cmd_script(struct perf_script *script)

signal(SIGINT, sig_handler);

+ /* override event processing functions */
+ if (script->show_task_events) {
+ script->tool.comm = process_comm_event;
+ script->tool.fork = process_fork_event;
+ script->tool.exit = process_exit_event;
+ }
+
ret = perf_session__process_events(script->session, &script->tool);

if (debug_mode)
@@ -1351,6 +1464,8 @@ int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
"display extended information from perf.data file"),
OPT_BOOLEAN('\0', "show-kernel-path", &symbol_conf.show_kernel_path,
"Show the path of [kernel.kallsyms]"),
+ OPT_BOOLEAN('\0', "show-task", &script.show_task_events,
+ "Show the fork/comm/exit events"),
OPT_END()
};
const char * const script_usage[] = {
--
1.7.11.7

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