From 991ae4eb36911fe9a99bef1c22b9578ceec3896a Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Sun, 27 Dec 2020 00:20:35 +0100 Subject: [PATCH] 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 ' 'disable ' when received the command, perf will scan the current evlist for 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 Tested-by: Arnaldo Carvalho de Melo Acked-by: Namhyung Kim Cc: Alexander Shishkin Cc: Alexei Budankov Cc: Ian Rogers Cc: Mark Rutland Cc: Michael Petlan Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lore.kernel.org/lkml/20201226232038.390883-2-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- 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 9087b22..5ab78dc 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -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. 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 7704c33..71061a9 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1938,18 +1938,14 @@ 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 3c054b8..3ec1236 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -611,14 +611,12 @@ 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 05363a7..c71c7e0 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; -- 2.7.4