Commit 47fddcb4 authored Dec 27, 2020 by Jiri Olsa Committed by Arnaldo Carvalho de Melo Jan 20, 2021

perf tools: Add 'ping' control command



Add a control 'ping' command to detect if perf is up and its control
interface is operational.

It will be used in following daemon patches to synchronize with record
session - when control interface is up and running, we know that perf
record is monitoring and ready to receive signals.

Example session:

  terminal 1:

    # mkfifo control ack
    # perf record --control=fifo:control,ack

  terminal 2:

    # echo ping > control
    # cat ack
    ack

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/20201226232038.390883-5-jolsa@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent f186cd61

tools/perf/Documentation/perf-record.txt

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -652,6 +652,7 @@ Available commands:
	'disable name' : disable event 'name'		'disable name' : disable event 'name'
	'snapshot' : AUX area tracing snapshot).		'snapshot' : AUX area tracing snapshot).
	'stop' : stop perf record		'stop' : stop perf record
			'ping' : ping

	'evlist [-v\|-g\|-F] : display all events		'evlist [-v\|-g\|-F] : display all events
	-F Show just the sample frequency used for each event.		-F Show just the sample frequency used for each event.

tools/perf/builtin-record.c

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1950,6 +1950,7 @@ static int __cmd_record(struct record rec, int argc, const char *argv)
	case EVLIST_CTL_CMD_ENABLE:		case EVLIST_CTL_CMD_ENABLE:
	case EVLIST_CTL_CMD_DISABLE:		case EVLIST_CTL_CMD_DISABLE:
	case EVLIST_CTL_CMD_EVLIST:		case EVLIST_CTL_CMD_EVLIST:
			case EVLIST_CTL_CMD_PING:
	default:		default:
	break;		break;
	}		}

tools/perf/builtin-stat.c

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -623,6 +623,7 @@ static void process_evlist(struct evlist *evlist, unsigned int interval)
	case EVLIST_CTL_CMD_UNSUPPORTED:		case EVLIST_CTL_CMD_UNSUPPORTED:
	case EVLIST_CTL_CMD_EVLIST:		case EVLIST_CTL_CMD_EVLIST:
	case EVLIST_CTL_CMD_STOP:		case EVLIST_CTL_CMD_STOP:
			case EVLIST_CTL_CMD_PING:
	default:		default:
	break;		break;
	}		}

tools/perf/util/evlist.c

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1943,6 +1943,9 @@ static int evlist__ctlfd_recv(struct evlist evlist, enum evlist_ctl_cmd cmd,
	} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_STOP_TAG,		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_STOP_TAG,
	(sizeof(EVLIST_CTL_CMD_STOP_TAG)-1))) {		(sizeof(EVLIST_CTL_CMD_STOP_TAG)-1))) {
	*cmd = EVLIST_CTL_CMD_STOP;		*cmd = EVLIST_CTL_CMD_STOP;
			} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_PING_TAG,
			(sizeof(EVLIST_CTL_CMD_PING_TAG)-1))) {
			*cmd = EVLIST_CTL_CMD_PING;
	}		}
	}		}

	@@ -2081,6 +2084,7 @@ int evlist__ctlfd_process(struct evlist evlist, enum evlist_ctl_cmd cmd)
	break;		break;
	case EVLIST_CTL_CMD_SNAPSHOT:		case EVLIST_CTL_CMD_SNAPSHOT:
	case EVLIST_CTL_CMD_STOP:		case EVLIST_CTL_CMD_STOP:
			case EVLIST_CTL_CMD_PING:
	break;		break;
	case EVLIST_CTL_CMD_ACK:		case EVLIST_CTL_CMD_ACK:
	case EVLIST_CTL_CMD_UNSUPPORTED:		case EVLIST_CTL_CMD_UNSUPPORTED:

tools/perf/util/evlist.h

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -332,6 +332,7 @@ struct evsel evlist__reset_weak_group(struct evlist evlist, struct evsel *evse
	#define EVLIST_CTL_CMD_SNAPSHOT_TAG "snapshot"		#define EVLIST_CTL_CMD_SNAPSHOT_TAG "snapshot"
	#define EVLIST_CTL_CMD_EVLIST_TAG "evlist"		#define EVLIST_CTL_CMD_EVLIST_TAG "evlist"
	#define EVLIST_CTL_CMD_STOP_TAG "stop"		#define EVLIST_CTL_CMD_STOP_TAG "stop"
			#define EVLIST_CTL_CMD_PING_TAG "ping"

	#define EVLIST_CTL_CMD_MAX_LEN 64		#define EVLIST_CTL_CMD_MAX_LEN 64

	@@ -343,6 +344,7 @@ enum evlist_ctl_cmd {
	EVLIST_CTL_CMD_SNAPSHOT,		EVLIST_CTL_CMD_SNAPSHOT,
	EVLIST_CTL_CMD_EVLIST,		EVLIST_CTL_CMD_EVLIST,
	EVLIST_CTL_CMD_STOP,		EVLIST_CTL_CMD_STOP,
			EVLIST_CTL_CMD_PING,
	};		};

	int evlist__parse_control(const char str, int ctl_fd, int ctl_fd_ack, bool ctl_fd_close);		int evlist__parse_control(const char str, int ctl_fd, int ctl_fd_ack, bool ctl_fd_close);