[PATCH 2/9] perf, tools: Add --branch-history option to report v3

[Andi Kleen]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Add a --branch-history option to perf report that changes all
the settings necessary for using the branches in callstacks.

This is just a short cut to make this nicer to use, it does
not enable any functionality by itself.

v2: Change sort order. Rename option to --branch-history to
be less confusing.
v3: Updates
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 tools/perf/Documentation/perf-report.txt |  5 +++++
 tools/perf/builtin-report.c              | 33 +++++++++++++++++++++++++++-----
 tools/perf/util/machine.c                | 12 ++++++------
 3 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index 4f0f3d9..23bce9b 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -231,6 +231,11 @@ OPTIONS
 	branch stacks and it will automatically switch to the branch view mode,
 	unless --no-branch-stack is used.
 
+--branch-history::
+	Add the addresses of sampled taken branches to the callstack.
+	This allows to examine the path the program took to each sample.
+	The data collection must have used -b (or -j) and -g.
+
 --objdump=<path>::
         Path to objdump binary.
 
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 1a2d7fc..e6d8ed0 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -315,8 +315,9 @@ static int report__setup_sample_type(struct report *rep)
 			return -EINVAL;
 		}
 		if (symbol_conf.use_callchain) {
-			ui__error("Selected -g but no callchain data. Did "
-				    "you call 'perf record' without -g?\n");
+			ui__error("Selected -g or --branch-history but no "
+				  "callchain data. Did\n"
+				  "you call 'perf record' without -g?\n");
 			return -1;
 		}
 	} else if (!rep->dont_use_callchains &&
@@ -631,6 +632,16 @@ parse_branch_mode(const struct option *opt __maybe_unused,
 }
 
 static int
+parse_branch_call_mode(const struct option *opt __maybe_unused,
+		  const char *str __maybe_unused, int unset)
+{
+	int *branch_mode = opt->value;
+
+	*branch_mode = !unset;
+	return 0;
+}
+
+static int
 parse_percent_limit(const struct option *opt, const char *str,
 		    int unset __maybe_unused)
 {
@@ -645,7 +656,7 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
 	struct perf_session *session;
 	struct stat st;
 	bool has_br_stack = false;
-	int branch_mode = -1;
+	int branch_mode = -1, branch_call_mode = -1;
 	int ret = -1;
 	char callchain_default_opt[] = "fractal,0.5,callee";
 	const char * const report_usage[] = {
@@ -754,7 +765,11 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
 	OPT_BOOLEAN(0, "group", &symbol_conf.event_group,
 		    "Show event group information together"),
 	OPT_CALLBACK_NOOPT('b', "branch-stack", &branch_mode, "",
-		    "use branch records for histogram filling", parse_branch_mode),
+		    "use branch records for per branch histogram filling",
+		    parse_branch_mode),
+	OPT_CALLBACK_NOOPT(0, "branch-history", &branch_call_mode, "",
+		    "add last branch records to call history",
+		    parse_branch_call_mode),
 	OPT_STRING(0, "objdump", &objdump_path, "path",
 		   "objdump binary to use for disassembly and annotations"),
 	OPT_BOOLEAN(0, "demangle", &symbol_conf.demangle,
@@ -804,8 +819,16 @@ repeat:
 	has_br_stack = perf_header__has_feat(&session->header,
 					     HEADER_BRANCH_STACK);
 
-	if (branch_mode == -1 && has_br_stack)
+	if (branch_mode == -1 && has_br_stack && branch_call_mode == -1)
 		sort__mode = SORT_MODE__BRANCH;
+	if (branch_call_mode != -1) {
+		callchain_param.branch_callstack = 1;
+		callchain_param.key = CCKEY_ADDRESS;
+		symbol_conf.use_callchain = true;
+		callchain_register_param(&callchain_param);
+		if (sort_order == default_sort_order)
+			sort_order = "srcline,symbol,dso";
+	}
 
 	/* sort__mode could be NORMAL if --no-branch-stack */
 	if (sort__mode == SORT_MODE__BRANCH) {
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 5238506..f828c87 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1379,15 +1379,15 @@ static int machine__resolve_callchain_sample(struct machine *machine,
 	 * - No annotations (should annotate somehow)
 	 */
 
-	if (branch->nr > PERF_MAX_BRANCH_DEPTH) {
-		pr_warning("corrupted branch chain. skipping...\n");
-		return 0;
-	}
-
-	if (callchain_param.branch_callstack) {
+	if (branch && callchain_param.branch_callstack) {
 		int nr = min(max_stack, (int)branch->nr);
 		struct branch_entry be[nr];
 
+		if (branch->nr > PERF_MAX_BRANCH_DEPTH) {
+			pr_warning("corrupted branch chain. skipping...\n");
+			return 0;
+		}
+
 		for (i = 0; i < nr; i++) {
 			if (callchain_param.order == ORDER_CALLEE) {
 				be[i] = branch->entries[i];
-- 
1.9.0

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