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>

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index c0ee766bca050ae88e1467cd057ef39f9a15fff4..f3161c9673e938ad77a6747a119b10e1aa4e12de 100644 (file)
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -652,6 +652,7 @@ Available commands:
   'disable name'     : disable event 'name'
   'snapshot'         : AUX area tracing snapshot).
   'stop'             : stop perf record
+  'ping'             : ping
 
   'evlist [-v|-g|-F] : display all events
                        -F  Show just the sample frequency used for each event.

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 36fc71097822ccfc4ada6999e8acce7b1d416d54..8a0127d4fb52193570df24310dc1476ed8f98f48 100644 (file)
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -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_DISABLE:
                        case EVLIST_CTL_CMD_EVLIST:
+                       case EVLIST_CTL_CMD_PING:
                        default:
                                break;
                        }

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 46a3f4ab13715858591692688c7f3aca1322c79a..a380e38ca937a9aa076c0a2dedcfc92f19965f0b 100644 (file)
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -623,6 +623,7 @@ static void process_evlist(struct evlist *evlist, unsigned int interval)
                case EVLIST_CTL_CMD_UNSUPPORTED:
                case EVLIST_CTL_CMD_EVLIST:
                case EVLIST_CTL_CMD_STOP:
+               case EVLIST_CTL_CMD_PING:
                default:
                        break;
                }

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index c6de70cefbaee6287ae7f2bcfab470c426ef8ace..61b2408821e57a92cbb24b5b100e3870146524b3 100644 (file)
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -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,
                                    (sizeof(EVLIST_CTL_CMD_STOP_TAG)-1))) {
                        *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;
                        case EVLIST_CTL_CMD_SNAPSHOT:
                        case EVLIST_CTL_CMD_STOP:
+                       case EVLIST_CTL_CMD_PING:
                                break;
                        case EVLIST_CTL_CMD_ACK:
                        case EVLIST_CTL_CMD_UNSUPPORTED:

diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 6f45c3630355bce1f75c701fdcf72c348c976b31..7c2521cb6b0957f4d41a465df48b1a2d24d52604 100644 (file)
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -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_EVLIST_TAG "evlist"
 #define EVLIST_CTL_CMD_STOP_TAG "stop"
+#define EVLIST_CTL_CMD_PING_TAG "ping"
 
 #define EVLIST_CTL_CMD_MAX_LEN 64
 
@@ -343,6 +344,7 @@ enum evlist_ctl_cmd {
        EVLIST_CTL_CMD_SNAPSHOT,
        EVLIST_CTL_CMD_EVLIST,
        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);