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Commit 9e207ddf authored by Kan Liang's avatar Kan Liang Committed by Arnaldo Carvalho de Melo
Browse files

perf report: Show call graph from reference events 



Introduce --show-ref-call-graph for perf report to print reference
callgraph for no callgraph event.

Here is an example.

 perf report --show-ref-call-graph --stdio

 # To display the perf.data header info, please use
 --header/--header-only options.
 #
 #
 # Total Lost Samples: 0
 #
 # Samples: 5  of event 'cpu/cpu-cycles,call-graph=fp/'
 # Event count (approx.): 144985
 #
 # Children      Self  Command  Shared Object     Symbol
 # ........  ........  .......  ................  ........................................
 #
    72.30%     0.00%  sleep    [kernel.vmlinux]  [k] entry_SYSCALL_64_fastpath
              |
              ---entry_SYSCALL_64_fastpath
                 |
                 |--22.62%-- __GI___libc_nanosleep
                  --77.38%-- [...]

......

 # Samples: 6  of event 'cpu/instructions,call-graph=no/', show reference callgraph
 # Event count (approx.): 172780
 #
 # Children      Self  Command  Shared Object     Symbol
 # ........  ........  .......  ................  ........................................
 #
    73.16%     0.00%  sleep    [kernel.vmlinux]  [k] entry_SYSCALL_64_fastpath
              |
              ---entry_SYSCALL_64_fastpath
                 |
                 |--31.44%-- __GI___libc_nanosleep
                  --68.56%-- [...]

Signed-off-by: default avatarKan Liang <kan.liang@intel.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1439289050-40510-3-git-send-email-kan.liang@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent f9db0d0f

tools/perf/Documentation/perf-report.txt

+11 −0
Original line number Diff line number Diff line
@@ -359,6 +359,17 @@ OPTIONS 
--full-source-path::

	Show the full path for source files for srcline output.



--show-ref-call-graph::

	When multiple events are sampled, it may not be needed to collect

	callgraphs for all of them. The sample sites are usually nearby,

	and it's enough to collect the callgraphs on a reference event.

	So user can use "call-graph=no" event modifier to disable callgraph

	for other events to reduce the overhead.

	However, perf report cannot show callgraphs for the event which

	disable the callgraph.

	This option extends the perf report to show reference callgraphs,

	which collected by reference event, in no callgraph event.



include::callchain-overhead-calculation.txt[]



SEE ALSO

tools/perf/builtin-report.c

+7 −0
Original line number Diff line number Diff line
@@ -316,6 +316,11 @@ static size_t hists__fprintf_nr_sample_events(struct hists *hists, struct report 
	if (evname != NULL)

		ret += fprintf(fp, " of event '%s'", evname);



	if (symbol_conf.show_ref_callgraph &&

	    strstr(evname, "call-graph=no")) {

		ret += fprintf(fp, ", show reference callgraph");

	}



	if (rep->mem_mode) {

		ret += fprintf(fp, "\n# Total weight : %" PRIu64, nr_events);

		ret += fprintf(fp, "\n# Sort order   : %s", sort_order ? : default_mem_sort_order);
@@ -740,6 +745,8 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused) 
			    itrace_parse_synth_opts),

	OPT_BOOLEAN(0, "full-source-path", &srcline_full_filename,

			"Show full source file name path for source lines"),

	OPT_BOOLEAN(0, "show-ref-call-graph", &symbol_conf.show_ref_callgraph,

		    "Show callgraph from reference event"),

	OPT_END()

	};

	struct perf_data_file file = {

tools/perf/ui/browsers/hists.c

+7 −2
Original line number Diff line number Diff line
@@ -1267,6 +1267,8 @@ static int hists__browser_title(struct hists *hists, 
	const char *ev_name = perf_evsel__name(evsel);

	char buf[512];

	size_t buflen = sizeof(buf);

	char ref[30] = " show reference callgraph, ";

	bool enable_ref = false;



	if (symbol_conf.filter_relative) {

		nr_samples = hists->stats.nr_non_filtered_samples;
@@ -1292,10 +1294,13 @@ static int hists__browser_title(struct hists *hists, 
		}

	}



	if (symbol_conf.show_ref_callgraph &&

	    strstr(ev_name, "call-graph=no"))

		enable_ref = true;

	nr_samples = convert_unit(nr_samples, &unit);

	printed = scnprintf(bf, size,

			   "Samples: %lu%c of event '%s', Event count (approx.): %" PRIu64,

			   nr_samples, unit, ev_name, nr_events);

			   "Samples: %lu%c of event '%s',%sEvent count (approx.): %" PRIu64,

			   nr_samples, unit, ev_name, enable_ref ? ref : " ", nr_events);





	if (hists->uid_filter_str)

tools/perf/util/hist.c

+6 −1
Original line number Diff line number Diff line
@@ -1141,7 +1141,12 @@ void hists__output_resort(struct hists *hists, struct ui_progress *prog) 
	struct hist_entry *n;

	u64 min_callchain_hits;

	struct perf_evsel *evsel = hists_to_evsel(hists);

	bool use_callchain = evsel ? (evsel->attr.sample_type & PERF_SAMPLE_CALLCHAIN) : symbol_conf.use_callchain;

	bool use_callchain;



	if (evsel && !symbol_conf.show_ref_callgraph)

		use_callchain = evsel->attr.sample_type & PERF_SAMPLE_CALLCHAIN;

	else

		use_callchain = symbol_conf.use_callchain;



	min_callchain_hits = hists->stats.total_period * (callchain_param.min_percent / 100);

tools/perf/util/symbol.h

+2 −1
Original line number Diff line number Diff line
@@ -106,7 +106,8 @@ struct symbol_conf { 
			filter_relative,

			show_hist_headers,

			branch_callstack,

			has_filter;

			has_filter,

			show_ref_callgraph;

	const char	*vmlinux_name,

			*kallsyms_name,

			*source_prefix,