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| author | Kan Liang <kan.liang@linux.intel.com> | 2020-03-19 23:25:16 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-04-18 15:05:01 +0300 |
| commit | d80da766d181555d0c846298b8c619c384c7d179 (patch) | |
| tree | 58ae9526bda2dd618a9f154055a20b1b4cecb956 /tools/perf/builtin-c2c.c | |
| parent | 13e0c844fa097f657bd8204fd574477c34f47a0c (diff) | |
| download | linux-d80da766d181555d0c846298b8c619c384c7d179.tar.xz | |
perf c2c: Add option to enable the LBR stitching approach
With the LBR stitching approach, the reconstructed LBR call stack can
break the HW limitation. However, it may reconstruct invalid call stacks
in some cases, e.g. exception handing such as setjmp/longjmp. Also, it
may impact the processing time especially when the number of samples
with stitched LBRs are huge.
Add an option to enable the approach.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Pavel Gerasimov <pavel.gerasimov@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vitaly Slobodskoy <vitaly.slobodskoy@intel.com>
Link: http://lore.kernel.org/lkml/20200319202517.23423-17-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-c2c.c')
| -rw-r--r-- | tools/perf/builtin-c2c.c | 12 |
1 files changed, 12 insertions, 0 deletions
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() }; |