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| author | Kan Liang <kan.liang@linux.intel.com> | 2020-03-19 23:25:15 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-04-18 15:05:01 +0300 |
| commit | 13e0c844fa097f657bd8204fd574477c34f47a0c (patch) | |
| tree | 4f6f4d1c0b86b211267dcfa80e99e91b87b60749 /tools/perf/Documentation/perf-top.txt | |
| parent | 680d125cd522d460b24ccc8b29f03cdb62dea23e (diff) | |
| download | linux-13e0c844fa097f657bd8204fd574477c34f47a0c.tar.xz | |
perf top: 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.
The option must be used with --call-graph lbr.
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>
Tested-by: Arnaldo Carvalho de Melo <acme@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/20200319202517.23423-16-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/Documentation/perf-top.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-top.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt index 487737a725e9..20227dabc208 100644 --- a/tools/perf/Documentation/perf-top.txt +++ b/tools/perf/Documentation/perf-top.txt @@ -319,6 +319,15 @@ Default is to monitor all CPUS. go straight to the histogram browser, just like 'perf top' with no events explicitely specified does. +--stitch-lbr:: + Show callgraph with stitched LBRs, which may have more complete + callgraph. The option must be used with --call-graph lbr recording. + 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. INTERACTIVE PROMPTING KEYS -------------------------- |