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: Kan Liang <kan.liang@intel.com>
Tested-by: Arnaldo 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: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index 7b07d19e2d54023d4820d702a19c4da202bda3a2..a18ba757a0ed9b8b6dabbfce1d2a02b870c5fdd7 100644 (file)
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -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

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index f301e865001f7f25f989523ced1c48b8cb1db113..62b285e32aa551093d9869798827a5be2cf3e1e5 100644 (file)
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -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 = {

diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
index f296b7348449e1b4d27d51ad5299d2e769d37ceb..10c7ec041039e15e63b2dece4fb173755e4ef7b5 100644 (file)
--- a/tools/perf/ui/browsers/hists.c
+++ b/tools/perf/ui/browsers/hists.c
@@ -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)

diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 1cd785b5b56eaa3729318464d3d5f49f0c5d7aa6..08b6cd945f1ece736249318835c044a735c6e29c 100644 (file)
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -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);
 

diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index b98ce51af1422f8e22415d6a104b4a19810940cc..a4cde92afbadf323c0a8e5b9200271b0ea79bb02 100644 (file)
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -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,