[PATCH 1/4] perf tools: Allow to enable/disable events via control file
From: Jiri Olsa
Date: Sat Dec 26 2020 - 18:23:48 EST
Adding new control events to enable/disable specific event.
The interface string for control file are:
'enable <EVENT NAME>'
'disable <EVENT NAME>'
when received the command, perf will scan the current evlist
for <EVENT NAME> and if found it's enabled/disabled.
Example session:
terminal 1:
# mkfifo control ack perf.pipe
# perf record --control=fifo:control,ack -D -1 --no-buffering -e 'sched:*' -o - > perf.pipe
terminal 2:
# cat perf.pipe | perf --no-pager script -i -
terminal 1:
Events disabled
NOTE Above message will show only after read side of the pipe ('>')
is started on 'terminal 2'. The 'terminal 1's bash does not execute
perf before that, hence the delyaed perf record message.
terminal 3:
# echo 'enable sched:sched_process_fork' > control
terminal 1:
event sched:sched_process_fork enabled
terminal 2:
bash 33349 [034] 149587.674295: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34056
bash 33349 [034] 149588.239521: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34057
terminal 3:
# echo 'enable sched:sched_wakeup_new' > control
terminal 1:
event sched:sched_wakeup_new enabled
terminal 2:
bash 33349 [034] 149632.228023: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34059
bash 33349 [034] 149632.228050: sched:sched_wakeup_new: bash:34059 [120] success=1 CPU:036
bash 33349 [034] 149633.950005: sched:sched_process_fork: comm=bash pid=33349 child_comm=bash child_pid=34060
bash 33349 [034] 149633.950030: sched:sched_wakeup_new: bash:34060 [120] success=1 CPU:036
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
tools/perf/Documentation/perf-record.txt | 8 +--
tools/perf/builtin-record.c | 8 +--
tools/perf/builtin-stat.c | 2 -
tools/perf/util/evlist.c | 63 ++++++++++++++++++++++--
4 files changed, 67 insertions(+), 14 deletions(-)
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 34cf651ee237..05a85da0f7c5 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -640,9 +640,11 @@ ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as follows.
Listen on ctl-fd descriptor for command to control measurement.
Available commands:
- 'enable' : enable events
- 'disable' : disable events
- 'snapshot': AUX area tracing snapshot).
+ 'enable' : enable events
+ 'disable' : disable events
+ 'enable name' : enable event 'name'
+ 'disable name' : disable event 'name'
+ 'snapshot' : AUX area tracing snapshot).
Measurements can be started with events disabled using --delay=-1 option. Optionally
send control command completion ('ack\n') to ack-fd descriptor to synchronize with the
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index fd3911650612..7302e7527d40 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1937,18 +1937,14 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
if (evlist__ctlfd_process(rec->evlist, &cmd) > 0) {
switch (cmd) {
- case EVLIST_CTL_CMD_ENABLE:
- pr_info(EVLIST_ENABLED_MSG);
- break;
- case EVLIST_CTL_CMD_DISABLE:
- pr_info(EVLIST_DISABLED_MSG);
- break;
case EVLIST_CTL_CMD_SNAPSHOT:
hit_auxtrace_snapshot_trigger(rec);
evlist__ctlfd_ack(rec->evlist);
break;
case EVLIST_CTL_CMD_ACK:
case EVLIST_CTL_CMD_UNSUPPORTED:
+ case EVLIST_CTL_CMD_ENABLE:
+ case EVLIST_CTL_CMD_DISABLE:
default:
break;
}
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 8cc24967bc27..3c6712ed5af7 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -578,14 +578,12 @@ static void process_evlist(struct evlist *evlist, unsigned int interval)
if (evlist__ctlfd_process(evlist, &cmd) > 0) {
switch (cmd) {
case EVLIST_CTL_CMD_ENABLE:
- pr_info(EVLIST_ENABLED_MSG);
if (interval)
process_interval();
break;
case EVLIST_CTL_CMD_DISABLE:
if (interval)
process_interval();
- pr_info(EVLIST_DISABLED_MSG);
break;
case EVLIST_CTL_CMD_SNAPSHOT:
case EVLIST_CTL_CMD_ACK:
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 05363a7247c4..c71c7e035641 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1957,6 +1957,64 @@ int evlist__ctlfd_ack(struct evlist *evlist)
return err;
}
+static int get_cmd_arg(char *cmd_data, size_t cmd_size, char **arg)
+{
+ char *data = cmd_data + cmd_size;
+
+ /* no argument */
+ if (!*data)
+ return 0;
+
+ /* there's argument */
+ if (*data == ' ') {
+ *arg = data + 1;
+ return 1;
+ }
+
+ /* malformed */
+ return -1;
+}
+
+static int evlist__ctlfd_enable(struct evlist *evlist, char *cmd_data, bool enable)
+{
+ struct evsel *evsel;
+ char *name;
+ int err;
+
+ err = get_cmd_arg(cmd_data,
+ enable ? sizeof(EVLIST_CTL_CMD_ENABLE_TAG) - 1 :
+ sizeof(EVLIST_CTL_CMD_DISABLE_TAG) - 1,
+ &name);
+ if (err < 0) {
+ pr_info("failed: wrong command\n");
+ return -1;
+ }
+
+ if (err) {
+ evsel = evlist__find_evsel_by_str(evlist, name);
+ if (evsel) {
+ if (enable)
+ evlist__enable_evsel(evlist, name);
+ else
+ evlist__disable_evsel(evlist, name);
+ pr_info("Event %s %s\n", evsel->name,
+ enable ? "enabled" : "disabled");
+ } else {
+ pr_info("failed: can't find '%s' event\n", name);
+ }
+ } else {
+ if (enable) {
+ evlist__enable(evlist);
+ pr_info(EVLIST_ENABLED_MSG);
+ } else {
+ evlist__disable(evlist);
+ pr_info(EVLIST_DISABLED_MSG);
+ }
+ }
+
+ return 0;
+}
+
int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
{
int err = 0;
@@ -1973,10 +2031,9 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
if (err > 0) {
switch (*cmd) {
case EVLIST_CTL_CMD_ENABLE:
- evlist__enable(evlist);
- break;
case EVLIST_CTL_CMD_DISABLE:
- evlist__disable(evlist);
+ err = evlist__ctlfd_enable(evlist, cmd_data,
+ *cmd == EVLIST_CTL_CMD_ENABLE);
break;
case EVLIST_CTL_CMD_SNAPSHOT:
break;
--
2.26.2