perf report: Support folded callchain mode on --stdio

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

For example, the 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
  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

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-and-Tested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1447047946-1691-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/tools/perf/ui/stdio/hist.c b/tools/perf/ui/stdio/hist.c
index dfcbc90146ef..ea7984932d9a 100644
--- a/tools/perf/ui/stdio/hist.c
+++ b/tools/perf/ui/stdio/hist.c
@@ -260,6 +260,58 @@ 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)
+{
+        const char *sep = symbol_conf.field_sep ?: ";";
+        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 ? "" : sep,
+                               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 += fprintf(fp, "%.2f%% ", percent);
+                ret += __callchain__fprintf_folded(fp, chain);
+                ret += fprintf(fp, "\n");
+                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 +330,9 @@ 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: