diff options
| -rw-r--r-- | tools/perf/Documentation/perf-script.txt | 11 | ||||
| -rw-r--r-- | tools/perf/builtin-script.c | 12 |
2 files changed, 23 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt index 963487e82edc..372dfd110e6d 100644 --- a/tools/perf/Documentation/perf-script.txt +++ b/tools/perf/Documentation/perf-script.txt @@ -440,6 +440,17 @@ include::itrace.txt[] --show-on-off-events:: Show the --switch-on/off events too. +--stitch-lbr:: + Show callgraph with stitched LBRs, which may have more complete + callgraph. The perf.data file must have been obtained using + perf record --call-graph lbr. + Disabled by default. In common cases with call stack overflows, + it can recreate better call stacks than the default lbr call stack + output. But this approach is not full proof. There can be cases + where it creates incorrect call stacks from incorrect matches. + The known limitations include exception handing such as + setjmp/longjmp will have calls/returns not match. + SEE ALSO -------- linkperf:perf-record[1], linkperf:perf-script-perl[1], diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index 06b511c0a539..a2236542900d 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -1697,6 +1697,7 @@ struct perf_script { bool show_cgroup_events; bool allocated; bool per_event_dump; + bool stitch_lbr; struct evswitch evswitch; struct perf_cpu_map *cpus; struct perf_thread_map *threads; @@ -1923,6 +1924,9 @@ static void process_event(struct perf_script *script, if (PRINT_FIELD(IP)) { struct callchain_cursor *cursor = NULL; + if (script->stitch_lbr) + al->thread->lbr_stitch_enable = true; + if (symbol_conf.use_callchain && sample->callchain && thread__resolve_callchain(al->thread, &callchain_cursor, evsel, sample, NULL, NULL, scripting_max_stack) == 0) @@ -3170,6 +3174,12 @@ static void script__setup_sample_type(struct perf_script *script) else callchain_param.record_mode = CALLCHAIN_FP; } + + if (script->stitch_lbr && (callchain_param.record_mode != CALLCHAIN_LBR)) { + pr_warning("Can't find LBR callchain. Switch off --stitch-lbr.\n" + "Please apply --call-graph lbr when recording.\n"); + script->stitch_lbr = false; + } } static int process_stat_round_event(struct perf_session *session, @@ -3481,6 +3491,8 @@ int cmd_script(int argc, const char **argv) "file", "file saving guest os /proc/kallsyms"), OPT_STRING(0, "guestmodules", &symbol_conf.default_guest_modules, "file", "file saving guest os /proc/modules"), + OPT_BOOLEAN('\0', "stitch-lbr", &script.stitch_lbr, + "Enable LBR callgraph stitching approach"), OPTS_EVSWITCH(&script.evswitch), OPT_END() }; |