[PATCH v2 2/8] perf tools: Support printing callchains with arrows

From: Namhyung Kim
Date: Wed Nov 16 2016 - 01:08:21 EST


The EVSEL__PRINT_CALLCHAIN_ARROW options can be used to print callchains
with arrows for readability. It will be used 'sched timehist' command
like below:

__schedule <- schedule <- schedule_timeout <- rcu_gp_kthread <- kthread <- ret_from_fork
__schedule <- schedule <- schedule_timeout <- rcu_gp_kthread <- kthread <- ret_from_fork
__schedule <- schedule <- worker_thread <- kthread <- ret_from_fork

Suggested-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/util/evsel.h | 1 +
tools/perf/util/evsel_fprintf.c | 6 ++++++
2 files changed, 7 insertions(+)

diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 8cd7cd227483..27fa3a343577 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -391,6 +391,7 @@ int perf_evsel__fprintf(struct perf_evsel *evsel,
#define EVSEL__PRINT_ONELINE (1<<4)
#define EVSEL__PRINT_SRCLINE (1<<5)
#define EVSEL__PRINT_UNKNOWN_AS_ADDR (1<<6)
+#define EVSEL__PRINT_CALLCHAIN_ARROW (1<<7)

struct callchain_cursor;

diff --git a/tools/perf/util/evsel_fprintf.c b/tools/perf/util/evsel_fprintf.c
index ccb602397b60..53bb614feafb 100644
--- a/tools/perf/util/evsel_fprintf.c
+++ b/tools/perf/util/evsel_fprintf.c
@@ -108,7 +108,9 @@ int sample__fprintf_callchain(struct perf_sample *sample, int left_alignment,
int print_oneline = print_opts & EVSEL__PRINT_ONELINE;
int print_srcline = print_opts & EVSEL__PRINT_SRCLINE;
int print_unknown_as_addr = print_opts & EVSEL__PRINT_UNKNOWN_AS_ADDR;
+ int print_arrow = print_opts & EVSEL__PRINT_CALLCHAIN_ARROW;
char s = print_oneline ? ' ' : '\t';
+ bool first = true;

if (sample->callchain) {
struct addr_location node_al;
@@ -124,6 +126,9 @@ int sample__fprintf_callchain(struct perf_sample *sample, int left_alignment,

printed += fprintf(fp, "%-*.*s", left_alignment, left_alignment, " ");

+ if (print_arrow && !first)
+ printed += fprintf(fp, " <-");
+
if (print_ip)
printed += fprintf(fp, "%c%16" PRIx64, s, node->ip);

@@ -158,6 +163,7 @@ int sample__fprintf_callchain(struct perf_sample *sample, int left_alignment,
printed += fprintf(fp, "\n");

callchain_cursor_advance(cursor);
+ first = false;
}
}

--
2.10.1