perf tools: Add FIFO file names as alternative options to --control

Enable the --control option to accept file names as an alternative to
file descriptors.

Example:

  $ mkfifo perf.control
  $ mkfifo perf.ack
  $ cat perf.ack &
  [1] 6808
  $ perf record --control fifo:perf.control,perf.ack -- sleep 300 &
  [2] 6810
  $ echo disable > perf.control
  $ Events disabled
  ack

  $ echo enable > perf.control
  $ Events enabled
  ack

  $ echo disable > perf.control
  $ Events disabled
  ack

  $ kill %2
  [ perf record: Woken up 4 times to write data ]
  $ [ perf record: Captured and wrote 0.018 MB perf.data (7 samples) ]

  [1]-  Done                    cat perf.ack
  [2]+  Terminated              perf record --control fifo:perf.control,perf.ack -- sleep 300
  $

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/20200902105707.11491-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 15 insertions, 3 deletions

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index ea072d47c560..14688710195c 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1047,7 +1047,17 @@ static int parse_control_option(const struct option *opt,
 {
 	struct perf_stat_config *config = opt->value;
 
-	return evlist__parse_control(str, &config->ctl_fd, &config->ctl_fd_ack);
+	return evlist__parse_control(str, &config->ctl_fd, &config->ctl_fd_ack, &config->ctl_fd_close);
+}
+
+static void close_control_option(struct perf_stat_config *config)
+{
+	if (config->ctl_fd_close) {
+		config->ctl_fd_close = false;
+		close(config->ctl_fd);
+		if (config->ctl_fd_ack >= 0)
+			close(config->ctl_fd_ack);
+	}
 }
 
 static struct option stat_options[] = {
@@ -1153,9 +1163,10 @@ static struct option stat_options[] = {
 		"libpfm4 event selector. use 'perf list' to list available events",
 		parse_libpfm_events_option),
 #endif
-	OPT_CALLBACK(0, "control", &stat_config, "fd:ctl-fd[,ack-fd]",
+	OPT_CALLBACK(0, "control", &stat_config, "fd:ctl-fd[,ack-fd] or fifo:ctl-fifo[,ack-fifo]",
 		     "Listen on ctl-fd descriptor for command to control measurement ('enable': enable events, 'disable': disable events).\n"
-		     "\t\t\t  Optionally send control command completion ('ack\\n') to ack-fd descriptor.",
+		     "\t\t\t  Optionally send control command completion ('ack\\n') to ack-fd descriptor.\n"
+		     "\t\t\t  Alternatively, ctl-fifo / ack-fifo will be opened and used as ctl-fd / ack-fd.",
 		      parse_control_option),
 	OPT_END()
 };
@@ -2398,6 +2409,7 @@ out:
 
 	metricgroup__rblist_exit(&stat_config.metric_events);
 	runtime_stat_delete(&stat_config);
+	close_control_option(&stat_config);
 
 	return status;
 }