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 c0ee766..f3161c9 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -652,6 +652,7 @@
'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 36fc710..8a0127d 100644
--- 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 46a3f4ab..a380e38 100644
--- 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 c6de70c..61b2408 100644
--- 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 6f45c36..7c2521c 100644
--- 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);