perf tools: Add 'evlist' control command

Add a new 'evlist' control command to display all the evlist events.
When it is received, perf will scan and print current evlist into perf
record terminal.

The interface string for control file is:

  evlist [-v|-g|-F]

The syntax follows perf evlist command:
  -F  Show just the sample frequency used for each event.
  -v  Show all fields.
  -g  Show event group information.

Example session:

  terminal 1:
    # mkfifo control ack
    # perf record --control=fifo:control,ack -e '{cycles,instructions}'

  terminal 2:
    # echo evlist > control

  terminal 1:
    cycles
    instructions
    dummy:HG

  terminal 2:
    # echo 'evlist -v' > control

  terminal 1:
    cycles: size: 120, { sample_period, sample_freq }: 4000, sample_type:            \
    IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, inherit: 1, freq: 1,    \
    sample_id_all: 1, exclude_guest: 1
    instructions: size: 120, config: 0x1, { sample_period, sample_freq }: 4000,      \
    sample_type: IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, inherit: 1, freq: 1,    \
    sample_id_all: 1, exclude_guest: 1
    dummy:HG: type: 1, size: 120, config: 0x9, { sample_period, sample_freq }: 4000, \
    sample_type: IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, inherit: 1, mmap: 1,    \
    comm: 1, freq: 1, task: 1, sample_id_all: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, \
     bpf_event: 1

  terminal 2:
    # echo 'evlist -g' > control

  terminal 1:
    {cycles,instructions}
    dummy:HG

  terminal 2:
    # echo 'evlist -F' > control

  terminal 1:
    cycles: sample_freq=4000
    instructions: sample_freq=4000
    dummy:HG: sample_freq=4000

This new evlist command is handy to get real event names when
wildcards are used.

Adding evsel_fprintf.c object to python/perf.so build, because
it's now evlist.c dependency.

Adding PYTHON_PERF define for python/perf.so compilation, so we
can use it to compile in only evsel__fprintf from evsel_fprintf.c
object.

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/20201226232038.390883-3-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index c71c7e035641..9e890b482220 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -24,6 +24,7 @@
 #include "bpf-event.h"
 #include "util/string2.h"
 #include "util/perf_api_probe.h"
+#include "util/evsel_fprintf.h"
 #include <signal.h>
 #include <unistd.h>
 #include <sched.h>
@@ -1936,6 +1937,9 @@ static int evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd,
 				    (sizeof(EVLIST_CTL_CMD_SNAPSHOT_TAG)-1))) {
 			*cmd = EVLIST_CTL_CMD_SNAPSHOT;
 			pr_debug("is snapshot\n");
+		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_EVLIST_TAG,
+				    (sizeof(EVLIST_CTL_CMD_EVLIST_TAG)-1))) {
+			*cmd = EVLIST_CTL_CMD_EVLIST;
 		}
 	}
 
@@ -2015,6 +2019,40 @@ static int evlist__ctlfd_enable(struct evlist *evlist, char *cmd_data, bool enab
 	return 0;
 }
 
+static int evlist__ctlfd_list(struct evlist *evlist, char *cmd_data)
+{
+	struct perf_attr_details details = { .verbose = false, };
+	struct evsel *evsel;
+	char *arg;
+	int err;
+
+	err = get_cmd_arg(cmd_data,
+			  sizeof(EVLIST_CTL_CMD_EVLIST_TAG) - 1,
+			  &arg);
+	if (err < 0) {
+		pr_info("failed: wrong command\n");
+		return -1;
+	}
+
+	if (err) {
+		if (!strcmp(arg, "-v")) {
+			details.verbose = true;
+		} else if (!strcmp(arg, "-g")) {
+			details.event_group = true;
+		} else if (!strcmp(arg, "-F")) {
+			details.freq = true;
+		} else {
+			pr_info("failed: wrong command\n");
+			return -1;
+		}
+	}
+
+	evlist__for_each_entry(evlist, evsel)
+		evsel__fprintf(evsel, &details, stderr);
+
+	return 0;
+}
+
 int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
 {
 	int err = 0;
@@ -2035,6 +2073,9 @@ int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd)
 				err = evlist__ctlfd_enable(evlist, cmd_data,
 							   *cmd == EVLIST_CTL_CMD_ENABLE);
 				break;
+			case EVLIST_CTL_CMD_EVLIST:
+				err = evlist__ctlfd_list(evlist, cmd_data);
+				break;
 			case EVLIST_CTL_CMD_SNAPSHOT:
 				break;
 			case EVLIST_CTL_CMD_ACK: