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perf tools: Add 'ping' control command

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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>
This commit is contained in:
Jiri Olsa 2020-12-27 00:20:38 +01:00 committed by Arnaldo Carvalho de Melo
parent f186cd6148
commit 47fddcb479
5 changed files with 9 additions and 0 deletions
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1
tools/perf/Documentation/perf-record.txt
View File

@ -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.

1
tools/perf/builtin-record.c
View File

@ -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;
}

1
tools/perf/builtin-stat.c
View File

@ -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;
}

4
tools/perf/util/evlist.c
View File

@ -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:

2
tools/perf/util/evlist.h
View File

@ -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);