[RFC/PATCH v2 1/4] perf report: Support folded callchain mode on --stdio

From: Namhyung Kim
Date: Mon Nov 02 2015 - 07:58:25 EST


Add new call chain option (-g) 'folded' to print callchains in a line.
The callchains are separated by semicolons, a space, then the
(absolute) percent values like in 'flat' mode.

For example, following 20 lines can be printed in 3 lines with the
folded output mode;

$ perf report -g flat --no-children | grep -v ^# | head -20
60.48% swapper [kernel.vmlinux] [k] intel_idle
54.60%
intel_idle
cpuidle_enter_state
cpuidle_enter
call_cpuidle
cpu_startup_entry
start_secondary

5.88%
intel_idle
cpuidle_enter_state
cpuidle_enter
call_cpuidle
cpu_startup_entry
rest_init
start_kernel
x86_64_start_reservations
x86_64_start_kernel

$ perf report -g folded --no-children | grep -v ^# | head -3
60.48% swapper [kernel.vmlinux] [k] intel_idle
intel_idle;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary 54.60%
intel_idle;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;rest_init;start_kernel;x86_64_start_reservations;x86_64_start_kernel 5.88%

This mode is supported only for --stdio now and intended to be used by
some scripts like in FlameGraphs[1]. Support for other UI might be
added later.

[1] http://www.brendangregg.com/FlameGraphs/cpuflamegraphs.html

Requested-by: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/ui/stdio/hist.c | 53 +++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/callchain.c | 6 +++++
tools/perf/util/callchain.h | 3 ++-
3 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/tools/perf/ui/stdio/hist.c b/tools/perf/ui/stdio/hist.c
index dfcbc90146ef..2c7436241912 100644
--- a/tools/perf/ui/stdio/hist.c
+++ b/tools/perf/ui/stdio/hist.c
@@ -260,6 +260,56 @@ static size_t callchain__fprintf_flat(FILE *fp, struct rb_root *tree,
return ret;
}

+static size_t __callchain__fprintf_folded(FILE *fp, struct callchain_node *node)
+{
+ struct callchain_list *chain;
+ size_t ret = 0;
+ char bf[1024];
+ bool first;
+
+ if (!node)
+ return 0;
+
+ ret += __callchain__fprintf_folded(fp, node->parent);
+
+ first = (ret == 0);
+ list_for_each_entry(chain, &node->val, list) {
+ if (chain->ip >= PERF_CONTEXT_MAX)
+ continue;
+ ret += fprintf(fp, "%s%s", first ? "" : ";",
+ callchain_list__sym_name(chain,
+ bf, sizeof(bf), false));
+ first = false;
+ }
+
+ return ret;
+}
+
+static size_t callchain__fprintf_folded(FILE *fp, struct rb_root *tree,
+ u64 total_samples)
+{
+ size_t ret = 0;
+ u32 entries_printed = 0;
+ struct callchain_node *chain;
+ struct rb_node *rb_node = rb_first(tree);
+
+ while (rb_node) {
+ double percent;
+
+ chain = rb_entry(rb_node, struct callchain_node, rb_node);
+ percent = chain->hit * 100.0 / total_samples;
+
+ ret += __callchain__fprintf_folded(fp, chain);
+ ret += fprintf(fp, " %6.2f%%\n", percent);
+ if (++entries_printed == callchain_param.print_limit)
+ break;
+
+ rb_node = rb_next(rb_node);
+ }
+
+ return ret;
+}
+
static size_t hist_entry_callchain__fprintf(struct hist_entry *he,
u64 total_samples, int left_margin,
FILE *fp)
@@ -278,6 +328,9 @@ static size_t hist_entry_callchain__fprintf(struct hist_entry *he,
case CHAIN_FLAT:
return callchain__fprintf_flat(fp, &he->sorted_chain, total_samples);
break;
+ case CHAIN_FOLDED:
+ return callchain__fprintf_folded(fp, &he->sorted_chain, total_samples);
+ break;
case CHAIN_NONE:
break;
default:
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 735ad48e1858..08cb220ba5ea 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -44,6 +44,10 @@ static int parse_callchain_mode(const char *value)
callchain_param.mode = CHAIN_GRAPH_REL;
return 0;
}
+ if (!strncmp(value, "folded", strlen(value))) {
+ callchain_param.mode = CHAIN_FOLDED;
+ return 0;
+ }
return -1;
}

@@ -218,6 +222,7 @@ rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,

switch (mode) {
case CHAIN_FLAT:
+ case CHAIN_FOLDED:
if (rnode->hit < chain->hit)
p = &(*p)->rb_left;
else
@@ -338,6 +343,7 @@ int callchain_register_param(struct callchain_param *param)
param->sort = sort_chain_graph_rel;
break;
case CHAIN_FLAT:
+ case CHAIN_FOLDED:
param->sort = sort_chain_flat;
break;
case CHAIN_NONE:
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index fce8161e54db..2f305384531f 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -43,7 +43,8 @@ enum chain_mode {
CHAIN_NONE,
CHAIN_FLAT,
CHAIN_GRAPH_ABS,
- CHAIN_GRAPH_REL
+ CHAIN_GRAPH_REL,
+ CHAIN_FOLDED,
};

enum chain_order {
--
2.6.2

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