[PATCH -tip v2 2/6] perf bts: Introduce new sub command 'perf bts trace'

[Akihiro Nagai <akihiro.nagai.hw@hitachi.com>]

Introduce new sub command 'perf bts trace'.
This command can parse and print bts log recorded by
'perf bts record'.

Usage:
 - First, record the bts log 'perf bts record <command>'
 - Second, parse and print bts log 'perf bts trace'

Output:
0xffffffff8146fe0e => 0x0000003806200b20
0x0000003806200b23 => 0x0000003806204910
0xffffffff8146fe0e => 0x0000003806204910
0xffffffff8146fe0e => 0x0000003806204936
0xffffffff8146fe0e => 0x000000380620493d
0x0000003806204981 => 0x00000038062049a3
0x00000038062049a7 => 0x0000003806204988
...

Changes in V2:
 - Update to the latest -tip tree

Signed-off-by: Akihiro Nagai <akihiro.nagai.hw@hitachi.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
---

 tools/perf/Documentation/perf-bts.txt |   14 ++++++--
 tools/perf/builtin-bts.c              |   56 +++++++++++++++++++++++++++++++--
 2 files changed, 64 insertions(+), 6 deletions(-)

diff --git a/tools/perf/Documentation/perf-bts.txt b/tools/perf/Documentation/perf-bts.txt
index 55a2fe6..5920dcc 100644
--- a/tools/perf/Documentation/perf-bts.txt
+++ b/tools/perf/Documentation/perf-bts.txt
@@ -3,22 +3,30 @@ perf-bts(1)
 
 NAME
 ----
-perf-bts - Record branch-trace-store log
+perf-bts - Record and print branch-trace-store log
 
 SYNOPSIS
 --------
 [verse]
-'perf bts' record <command>
+'perf bts' [<options>] {record|trace}
 
 DESCRIPTION
 -----------
-This command can record branch-trace-store log.
+This command can record and print branch-trace-store log.
 Branch-trace-store is a facility of processors. It can record
 address of branch to/from on every branch instruction and interrupt.
 
 'perf bts record <command>' records branch-trace-store log while specified
 command is executing. And, save to the file "perf.data".
 
+'perf bts trace' parses recorded branch-trace-store log and prints it.
+
+OPTIONS
+-------
+-i::
+--input=::
+        Specify input file name to analyze.
+
 SEE ALSO
 --------
 linkperf:perf-record[1]
diff --git a/tools/perf/builtin-bts.c b/tools/perf/builtin-bts.c
index 587cfad..0d546d8 100644
--- a/tools/perf/builtin-bts.c
+++ b/tools/perf/builtin-bts.c
@@ -1,10 +1,26 @@
 #include "builtin.h"
 #include "perf.h"
 #include "util/parse-options.h"
+#include "util/session.h"
+#include "util/cache.h"
+#include "util/trace-event.h"
+#include <inttypes.h>
+
+/* format string of specifying min width to print address */
+#if __WORDSIZE == 32
+#define FMT_ADDR_WIDTH	"10"		/* length of "0x" + 32bit address */
+#else
+#define FMT_ADDR_WIDTH	"18"		/* length of "0x" + 64bit address */
+#endif
+/* format string to print address */
+#define FMT_ADDR	"%#0" FMT_ADDR_WIDTH "llx"
+
+/* default input file name to analyze */
+static const char *input_name = "perf.data";
 
 static const char * const bts_usage[] = {
-	"perf bts record <command>",
-	NULL,
+	"perf bts [<options>] {record|trace}",
+	NULL
 };
 
 /* arguments to call 'perf record' */
@@ -16,11 +32,41 @@ static const char * const record_args[] = {
 	"-d",
 };
 
-/* dummy struct option to call parse_options() */
 static const struct option bts_options[] = {
+	OPT_STRING('i', "input", &input_name, "file", "input file name"),
 	OPT_END()
 };
 
+static int process_sample_event(event_t *event __unused,
+	struct sample_data *sample, struct perf_session *session __unused)
+{
+	/* sample->ip is 'from address', sample->addr is 'to address' */
+	printf(FMT_ADDR " => " FMT_ADDR "\n", sample->ip, sample->addr);
+
+	return 0;
+}
+
+static struct perf_event_ops event_ops = {
+	.sample			= process_sample_event,
+	.ordered_samples	= false,
+};
+
+static int __cmd_trace(void)
+{
+	struct perf_session *session;
+
+	session = perf_session__new(input_name, O_RDONLY, 0, false);
+	if (!session) {
+		fprintf(stderr, "failed to create perf_session.\n");
+		return -ENOMEM;
+	}
+
+	perf_session__process_events(session, &event_ops);
+	perf_session__delete(session);
+
+	return 0;
+}
+
 static int __cmd_record(int argc, const char **argv)
 {
 	unsigned int rec_argc, i, j;
@@ -55,6 +101,10 @@ int cmd_bts(int argc, const char **argv, const char *prefix __used)
 
 	if (!strncmp(argv[0], "record", 6))
 		return __cmd_record(argc, argv);
+	else if (!strncmp(argv[0], "trace", 5)) {
+		setup_pager();
+		return __cmd_trace();
+	}
 	else
 		usage_with_options(bts_usage, bts_options);