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Subject: [PATCH v1 6/8] perf record: introduce control descriptors and
 --ctl-fd[-ack] options
From:   Alexey Budankov <alexey.budankov@linux.intel.com>
To:     Arnaldo Carvalho de Melo <acme@redhat.com>
Cc:     Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Andi Kleen <ak@linux.intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
References: <825a5132-b58d-c0b6-b050-5a6040386ec7@linux.intel.com>
Organization: Intel Corp.
Message-ID: <8f1b6db8-1d54-06d4-18b9-a1e24ff0e2cb@linux.intel.com>
Date:   Fri, 27 Mar 2020 11:49:49 +0300
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Introduce control file descriptors and --ctl-fd[-ack] options to pass
control descriptors from command line. Extend --delay option with -1
value to start collection in paused mode to be resumed later by resume
command provided via control file descriptor.

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
---
 tools/perf/builtin-record.c | 18 ++++++++++++++----
 tools/perf/builtin-trace.c  |  2 +-
 tools/perf/util/record.h    |  4 +++-
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 4c301466101b..f99751943b40 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1621,8 +1621,12 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 	}
 
 	if (opts->initial_delay) {
-		usleep(opts->initial_delay * USEC_PER_MSEC);
-		evlist__enable(rec->evlist);
+		pr_info(PERF_EVLIST__PAUSED_MSG);
+		if (opts->initial_delay > 0) {
+			usleep(opts->initial_delay * USEC_PER_MSEC);
+			evlist__enable(rec->evlist);
+			pr_info(PERF_EVLIST__RESUMED_MSG);
+		}
 	}
 
 	trigger_ready(&auxtrace_snapshot_trigger);
@@ -2218,6 +2222,8 @@ static struct record record = {
 			.default_per_cpu = true,
 		},
 		.mmap_flush          = MMAP_FLUSH_DEFAULT,
+		.ctl_fd              = -1,
+		.ctl_fd_ack          = -1,
 	},
 	.tool = {
 		.sample		= process_sample_event,
@@ -2320,8 +2326,8 @@ static struct option __record_options[] = {
 	OPT_CALLBACK('G', "cgroup", &record.evlist, "name",
 		     "monitor event in cgroup name only",
 		     parse_cgroups),
-	OPT_UINTEGER('D', "delay", &record.opts.initial_delay,
-		  "ms to wait before starting measurement after program start"),
+	OPT_INTEGER('D', "delay", &record.opts.initial_delay,
+		  "ms to wait before starting measurement after program start (-1: start paused)"),
 	OPT_BOOLEAN(0, "kcore", &record.opts.kcore, "copy /proc/kcore"),
 	OPT_STRING('u', "uid", &record.opts.target.uid_str, "user",
 		   "user to profile"),
@@ -2405,6 +2411,10 @@ static struct option __record_options[] = {
 #endif
 	OPT_CALLBACK(0, "max-size", &record.output_max_size,
 		     "size", "Limit the maximum size of the output file", parse_output_max_size),
+	OPT_INTEGER(0, "ctl-fd", &record.opts.ctl_fd,
+		    "Listen on fd descriptor for command to control measurement ('r': resume, 'p': pause)"),
+	OPT_INTEGER(0, "ctl-fd-ack", &record.opts.ctl_fd_ack,
+		    "Send control command completion ('a') to fd ack descriptor"),
 	OPT_END()
 };
 
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 01d542007c8b..4088d099f8bd 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -4778,7 +4778,7 @@ int cmd_trace(int argc, const char **argv)
 			"per thread proc mmap processing timeout in ms"),
 	OPT_CALLBACK('G', "cgroup", &trace, "name", "monitor event in cgroup name only",
 		     trace__parse_cgroups),
-	OPT_UINTEGER('D', "delay", &trace.opts.initial_delay,
+	OPT_INTEGER('D', "delay", &trace.opts.initial_delay,
 		     "ms to wait before starting measurement after program "
 		     "start"),
 	OPTS_EVSWITCH(&trace.evswitch),
diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h
index 5421fd2ad383..138f914f4ea9 100644
--- a/tools/perf/util/record.h
+++ b/tools/perf/util/record.h
@@ -59,7 +59,7 @@ struct record_opts {
 	const char    *auxtrace_snapshot_opts;
 	const char    *auxtrace_sample_opts;
 	bool	      sample_transaction;
-	unsigned      initial_delay;
+	int	      initial_delay;
 	bool	      use_clockid;
 	clockid_t     clockid;
 	u64	      clockid_res_ns;
@@ -67,6 +67,8 @@ struct record_opts {
 	int	      affinity;
 	int	      mmap_flush;
 	unsigned int  comp_level;
+	int	      ctl_fd;
+	int	      ctl_fd_ack;
 };
 
 extern const char * const *record_usage;
-- 
2.24.1