diff options
| -rw-r--r-- | tools/perf/Documentation/perf-c2c.txt | 11 | ||||
| -rw-r--r-- | tools/perf/builtin-c2c.c | 12 |
2 files changed, 23 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-c2c.txt b/tools/perf/Documentation/perf-c2c.txt index e6150f21267d..2133eb320cb0 100644 --- a/tools/perf/Documentation/perf-c2c.txt +++ b/tools/perf/Documentation/perf-c2c.txt @@ -111,6 +111,17 @@ REPORT OPTIONS --display:: Switch to HITM type (rmt, lcl) to display and sort on. Total HITMs as default. +--stitch-lbr:: + Show callgraph with stitched LBRs, which may have more complete + callgraph. The perf.data file must have been obtained using + perf c2c 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. + C2C RECORD ---------- The perf c2c record command setup options related to HITM cacheline analysis diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c index 246ac0b4d54f..0d544c4fb4be 100644 --- a/tools/perf/builtin-c2c.c +++ b/tools/perf/builtin-c2c.c @@ -95,6 +95,7 @@ struct perf_c2c { bool use_stdio; bool stats_only; bool symbol_full; + bool stitch_lbr; /* HITM shared clines stats */ struct c2c_stats hitm_stats; @@ -273,6 +274,9 @@ static int process_sample_event(struct perf_tool *tool __maybe_unused, return -1; } + if (c2c.stitch_lbr) + al.thread->lbr_stitch_enable = true; + ret = sample__resolve_callchain(sample, &callchain_cursor, NULL, evsel, &al, sysctl_perf_event_max_stack); if (ret) @@ -2601,6 +2605,12 @@ static int setup_callchain(struct evlist *evlist) } } + if (c2c.stitch_lbr && (mode != CALLCHAIN_LBR)) { + ui__warning("Can't find LBR callchain. Switch off --stitch-lbr.\n" + "Please apply --call-graph lbr when recording.\n"); + c2c.stitch_lbr = false; + } + callchain_param.record_mode = mode; callchain_param.min_percent = 0; return 0; @@ -2752,6 +2762,8 @@ static int perf_c2c__report(int argc, const char **argv) OPT_STRING('c', "coalesce", &coalesce, "coalesce fields", "coalesce fields: pid,tid,iaddr,dso"), OPT_BOOLEAN('f', "force", &symbol_conf.force, "don't complain, do it"), + OPT_BOOLEAN(0, "stitch-lbr", &c2c.stitch_lbr, + "Enable LBR callgraph stitching approach"), OPT_PARENT(c2c_options), OPT_END() }; |