summaryrefslogtreecommitdiff
path: root/tools/perf/util/evlist.c
diff options
context:
space:
mode:
authorJiri Olsa <jolsa@kernel.org>2020-12-27 02:20:35 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2021-01-20 20:34:21 +0300
commit991ae4eb36911fe9a99bef1c22b9578ceec3896a (patch)
treef0349a5cb01c3216a16fcc5e9af21a73539478e8 /tools/perf/util/evlist.c
parente8b2db07810a0449cb754095c2d85cdfb39e3f57 (diff)
downloadlinux-991ae4eb36911fe9a99bef1c22b9578ceec3896a.tar.xz
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>
Diffstat (limited to 'tools/perf/util/evlist.c')
-rw-r--r--tools/perf/util/evlist.c63
1 files changed, 60 insertions, 3 deletions
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;