perf tools: Allow to enable/disable events via control file

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

Committer testing:

If I use 'sched:*' and then enable all events, I can't get 'perf record'
to react to further commands, so I tested it with:

  [root@five ~]# perf record --control=fifo:control,ack -D -1 --no-buffering -e 'sched:sched_process_*' -o - > perf.pipe
  Events disabled
  Events enabled
  Events disabled

And then it works as expected, so we need to fix this pre-existing
problem.

Another issue, we need to check if a event is already enabled or
disabled and change the message to be clearer, i.e.:

  [root@five ~]# perf record --control=fifo:control,ack -D -1 --no-buffering -e 'sched:sched_process_*' -o - > perf.pipe
  Events disabled

If we receive a 'disable' command, then it should say:

  [root@five ~]# perf record --control=fifo:control,ack -D -1 --no-buffering -e 'sched:sched_process_*' -o - > perf.pipe
  Events disabled
  Events already disabled

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Budankov <abudankov@huawei.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20201226232038.390883-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jiri Olsa 2020-12-27 00:20:35 +01:00 committed by Arnaldo Carvalho de Melo
parent e8b2db0781
commit 991ae4eb36
4 changed files with 67 additions and 14 deletions

View File

@ -646,9 +646,11 @@ 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. Listen on ctl-fd descriptor for command to control measurement.
Available commands: Available commands:
'enable' : enable events 'enable' : enable events
'disable' : disable events 'disable' : disable events
'snapshot': AUX area tracing snapshot). '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 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 send control command completion ('ack\n') to ack-fd descriptor to synchronize with the

View File

@ -1938,18 +1938,14 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
if (evlist__ctlfd_process(rec->evlist, &cmd) > 0) { if (evlist__ctlfd_process(rec->evlist, &cmd) > 0) {
switch (cmd) { 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: case EVLIST_CTL_CMD_SNAPSHOT:
hit_auxtrace_snapshot_trigger(rec); hit_auxtrace_snapshot_trigger(rec);
evlist__ctlfd_ack(rec->evlist); evlist__ctlfd_ack(rec->evlist);
break; break;
case EVLIST_CTL_CMD_ACK: case EVLIST_CTL_CMD_ACK:
case EVLIST_CTL_CMD_UNSUPPORTED: case EVLIST_CTL_CMD_UNSUPPORTED:
case EVLIST_CTL_CMD_ENABLE:
case EVLIST_CTL_CMD_DISABLE:
default: default:
break; break;
} }

View File

@ -611,14 +611,12 @@ static void process_evlist(struct evlist *evlist, unsigned int interval)
if (evlist__ctlfd_process(evlist, &cmd) > 0) { if (evlist__ctlfd_process(evlist, &cmd) > 0) {
switch (cmd) { switch (cmd) {
case EVLIST_CTL_CMD_ENABLE: case EVLIST_CTL_CMD_ENABLE:
pr_info(EVLIST_ENABLED_MSG);
if (interval) if (interval)
process_interval(); process_interval();
break; break;
case EVLIST_CTL_CMD_DISABLE: case EVLIST_CTL_CMD_DISABLE:
if (interval) if (interval)
process_interval(); process_interval();
pr_info(EVLIST_DISABLED_MSG);
break; break;
case EVLIST_CTL_CMD_SNAPSHOT: case EVLIST_CTL_CMD_SNAPSHOT:
case EVLIST_CTL_CMD_ACK: case EVLIST_CTL_CMD_ACK:

View File

@ -1957,6 +1957,64 @@ int evlist__ctlfd_ack(struct evlist *evlist)
return err; 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 evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
{ {
int err = 0; int err = 0;
@ -1973,10 +2031,9 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
if (err > 0) { if (err > 0) {
switch (*cmd) { switch (*cmd) {
case EVLIST_CTL_CMD_ENABLE: case EVLIST_CTL_CMD_ENABLE:
evlist__enable(evlist);
break;
case EVLIST_CTL_CMD_DISABLE: case EVLIST_CTL_CMD_DISABLE:
evlist__disable(evlist); err = evlist__ctlfd_enable(evlist, cmd_data,
*cmd == EVLIST_CTL_CMD_ENABLE);
break; break;
case EVLIST_CTL_CMD_SNAPSHOT: case EVLIST_CTL_CMD_SNAPSHOT:
break; break;