[tip:perf/core] perf report: Tag branch type/flag on "to" and tag cycles on "from"

From: tip-bot for Jin Yao
Date: Wed Jul 26 2017 - 13:29:14 EST

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Commit-ID: a1a8bed32de197801bb861fbf13cd01496df3e05
Gitweb: http://git.kernel.org/tip/a1a8bed32de197801bb861fbf13cd01496df3e05
Author: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
AuthorDate: Mon, 24 Jul 2017 19:09:07 +0800
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 25 Jul 2017 22:46:35 -0300

perf report: Tag branch type/flag on "to" and tag cycles on "from"

Current --branch-history LBR annotation displays confused data. For
example, each cycles report is duplicated on both "from" and "to"
entries.

For example:

perf report --branch-history --no-children --stdio

--2.32%--main div.c:39 (COND_BWD CROSS_2M predicted:49.7% cycles:1)
main div.c:44 (predicted:49.7% cycles:1)
main div.c:42 (RET CROSS_2M cycles:2)
compute_flag div.c:28 (cycles:2)
compute_flag div.c:27 (RET CROSS_2M cycles:1)
rand rand.c:28 (cycles:1)
rand rand.c:28 (RET CROSS_2M cycles:1)
__random random.c:298 (cycles:1)
__random random.c:297 (COND_BWD CROSS_2M cycles:1)
__random random.c:295 (cycles:1)
__random random.c:295 (COND_BWD CROSS_2M cycles:1)
__random random.c:295 (cycles:1)
__random random.c:295 (RET CROSS_2M cycles:9)

The cycles should be tagged only on the "from". It's for the code block
that ends with "from", not for "to".

Another issue is the "predicted:49.7%" is duplicated too (tag on both
"from" and "to").

This patch tags the branch type/flag on "to" and tag the cycles on
"from".

For example:

--2.32%--main div.c:39 (COND_BWD CROSS_2M predicted:49.7%)
main div.c:44 (cycles:1)
main div.c:42 (RET CROSS_2M)
compute_flag div.c:28 (cycles:2)
compute_flag div.c:27 (RET CROSS_2M)
rand rand.c:28 (cycles:1)
rand rand.c:28 (RET CROSS_2M)
__random random.c:298 (cycles:1)
__random random.c:297 (COND_BWD CROSS_2M)
__random random.c:295 (cycles:1)
__random random.c:295 (COND_BWD CROSS_2M)
__random random.c:295 (cycles:1)
__random random.c:295 (RET CROSS_2M)
|
--2.23%--__random_r random_r.c:392 (cycles:9)

In this example, The "main div.c:39 (COND_BWD CROSS_2M predicted:49.7%)"
is "to" of branch and "main div.c:44 (cycles:1)" is "from" of branch.
It should be easier for understanding than before.

Signed-off-by: Yao Jin <yao.jin@xxxxxxxxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1500894547-18411-1-git-send-email-yao.jin@xxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/branch.h | 11 ++--
tools/perf/util/callchain.c | 148 +++++++++++++++++++++++++++++++-------------
2 files changed, 111 insertions(+), 48 deletions(-)

diff --git a/tools/perf/util/branch.h b/tools/perf/util/branch.h
index 686f2b6..1e3c7c5 100644
--- a/tools/perf/util/branch.h
+++ b/tools/perf/util/branch.h
@@ -5,11 +5,12 @@
#include "../perf.h"

struct branch_type_stat {
- u64 counts[PERF_BR_MAX];
- u64 cond_fwd;
- u64 cond_bwd;
- u64 cross_4k;
- u64 cross_2m;
+ bool branch_to;
+ u64 counts[PERF_BR_MAX];
+ u64 cond_fwd;
+ u64 cond_bwd;
+ u64 cross_4k;
+ u64 cross_2m;
};

struct branch_flags;
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 1f53641..f320b07 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -563,20 +563,33 @@ fill_node(struct callchain_node *node, struct callchain_cursor *cursor)
if (cursor_node->branch) {
call->branch_count = 1;

- if (cursor_node->branch_flags.predicted)
- call->predicted_count = 1;
-
- if (cursor_node->branch_flags.abort)
- call->abort_count = 1;
-
- call->cycles_count = cursor_node->branch_flags.cycles;
- call->iter_count = cursor_node->nr_loop_iter;
- call->samples_count = cursor_node->samples;
-
- branch_type_count(&call->brtype_stat,
- &cursor_node->branch_flags,
- cursor_node->branch_from,
- cursor_node->ip);
+ if (cursor_node->branch_from) {
+ /*
+ * branch_from is set with value somewhere else
+ * to imply it's "to" of a branch.
+ */
+ call->brtype_stat.branch_to = true;
+
+ if (cursor_node->branch_flags.predicted)
+ call->predicted_count = 1;
+
+ if (cursor_node->branch_flags.abort)
+ call->abort_count = 1;
+
+ branch_type_count(&call->brtype_stat,
+ &cursor_node->branch_flags,
+ cursor_node->branch_from,
+ cursor_node->ip);
+ } else {
+ /*
+ * It's "from" of a branch
+ */
+ call->brtype_stat.branch_to = false;
+ call->cycles_count =
+ cursor_node->branch_flags.cycles;
+ call->iter_count = cursor_node->nr_loop_iter;
+ call->samples_count = cursor_node->samples;
+ }
}

list_add_tail(&call->list, &node->val);
@@ -685,20 +698,32 @@ static enum match_result match_chain(struct callchain_cursor_node *node,
if (node->branch) {
cnode->branch_count++;

- if (node->branch_flags.predicted)
- cnode->predicted_count++;
-
- if (node->branch_flags.abort)
- cnode->abort_count++;
-
- cnode->cycles_count += node->branch_flags.cycles;
- cnode->iter_count += node->nr_loop_iter;
- cnode->samples_count += node->samples;
-
- branch_type_count(&cnode->brtype_stat,
- &node->branch_flags,
- node->branch_from,
- node->ip);
+ if (node->branch_from) {
+ /*
+ * It's "to" of a branch
+ */
+ cnode->brtype_stat.branch_to = true;
+
+ if (node->branch_flags.predicted)
+ cnode->predicted_count++;
+
+ if (node->branch_flags.abort)
+ cnode->abort_count++;
+
+ branch_type_count(&cnode->brtype_stat,
+ &node->branch_flags,
+ node->branch_from,
+ node->ip);
+ } else {
+ /*
+ * It's "from" of a branch
+ */
+ cnode->brtype_stat.branch_to = false;
+ cnode->cycles_count +=
+ node->branch_flags.cycles;
+ cnode->iter_count += node->nr_loop_iter;
+ cnode->samples_count += node->samples;
+ }
}

return MATCH_EQ;
@@ -1236,27 +1261,26 @@ static int count_pri64_printf(int idx, const char *str, u64 value, char *bf, int
return printed;
}

-static int count_float_printf(int idx, const char *str, float value, char *bf, int bfsize)
+static int count_float_printf(int idx, const char *str, float value,
+ char *bf, int bfsize, float threshold)
{
int printed;

+ if (threshold != 0.0 && value < threshold)
+ return 0;
+
printed = scnprintf(bf, bfsize, "%s%s:%.1f%%", (idx) ? " " : " (", str, value);

return printed;
}

-static int counts_str_build(char *bf, int bfsize,
- u64 branch_count, u64 predicted_count,
- u64 abort_count, u64 cycles_count,
- u64 iter_count, u64 samples_count,
- struct branch_type_stat *brtype_stat)
+static int branch_to_str(char *bf, int bfsize,
+ u64 branch_count, u64 predicted_count,
+ u64 abort_count,
+ struct branch_type_stat *brtype_stat)
{
- u64 cycles;
int printed, i = 0;

- if (branch_count == 0)
- return scnprintf(bf, bfsize, " (calltrace)");
-
printed = branch_type_str(brtype_stat, bf, bfsize);
if (printed)
i++;
@@ -1264,15 +1288,29 @@ static int counts_str_build(char *bf, int bfsize,
if (predicted_count < branch_count) {
printed += count_float_printf(i++, "predicted",
predicted_count * 100.0 / branch_count,
- bf + printed, bfsize - printed);
+ bf + printed, bfsize - printed, 0.0);
}

if (abort_count) {
printed += count_float_printf(i++, "abort",
abort_count * 100.0 / branch_count,
- bf + printed, bfsize - printed);
+ bf + printed, bfsize - printed, 0.1);
}

+ if (i)
+ printed += scnprintf(bf + printed, bfsize - printed, ")");
+
+ return printed;
+}
+
+static int branch_from_str(char *bf, int bfsize,
+ u64 branch_count,
+ u64 cycles_count, u64 iter_count,
+ u64 samples_count)
+{
+ int printed = 0, i = 0;
+ u64 cycles;
+
cycles = cycles_count / branch_count;
if (cycles) {
printed += count_pri64_printf(i++, "cycles",
@@ -1287,10 +1325,34 @@ static int counts_str_build(char *bf, int bfsize,
}

if (i)
- return scnprintf(bf + printed, bfsize - printed, ")");
+ printed += scnprintf(bf + printed, bfsize - printed, ")");

- bf[0] = 0;
- return 0;
+ return printed;
+}
+
+static int counts_str_build(char *bf, int bfsize,
+ u64 branch_count, u64 predicted_count,
+ u64 abort_count, u64 cycles_count,
+ u64 iter_count, u64 samples_count,
+ struct branch_type_stat *brtype_stat)
+{
+ int printed;
+
+ if (branch_count == 0)
+ return scnprintf(bf, bfsize, " (calltrace)");
+
+ if (brtype_stat->branch_to) {
+ printed = branch_to_str(bf, bfsize, branch_count,
+ predicted_count, abort_count, brtype_stat);
+ } else {
+ printed = branch_from_str(bf, bfsize, branch_count,
+ cycles_count, iter_count, samples_count);
+ }
+
+ if (!printed)
+ bf[0] = 0;
+
+ return printed;
}

static int callchain_counts_printf(FILE *fp, char *bf, int bfsize,

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