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Kan Liang b1d1429b18 perf report: 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.

  # To display the perf.data header info, please use
  # --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 6K of event 'cycles'
  # Event count (approx.): 6492797701
  #
  # Children      Self  Command          Shared Object       Symbol
  # ........  ........  ...............  ..................
  # .................................
  #
    99.99%    99.99%  tchain_edit      tchain_edit        [.] f43
            |
            ---main
               f1
               f2
               f3
               f4
               f5
               f6
               f7
               f8
               f9
               f10
               f11
               f12
               f13
               f14
               f15
               f16
               f17
               f18
               f19
               f20
               f21
               f22
               f23
               f24
               f25
               f26
               f27
               f28
               f29
               f30
               f31
               |
                --99.65%--f32
                          f33
                          f34
                          f35
                          f36
                          f37
                          f38
                          f39
                          f40
                          f41
                          f42
                          f43

Committer testing:

  $ perf record --call-graph lbr /wb/tchain_edit
  [ perf record: Woken up 23 times to write data ]
  [ perf record: Captured and wrote 5.578 MB perf.data (6839 samples) ]
  $ perf report --header-only | egrep 'cpu(desc|.*capabilities)'
  # cpudesc : Intel(R) Core(TM) i5-7500 CPU @ 3.40GHz
  # cpu pmu capabilities: branches=32, max_precise=3, pmu_name=skylake
  $

Before:

  $ perf report --no-children --stdio
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 6K of event 'cycles:u'
  # Event count (approx.): 6459523879
  #
  # Overhead  Command      Shared Object     Symbol
  # ........  ...........  ................  .......................
  #
      99.95%  tchain_edit  tchain_edit       [.] f43
              |
               --99.92%--f43
                         f42
                         f41
                         f40
                         f39
                         f38
                         f37
                         f36
                         f35
                         f34
                         f33
                         f32
                         f31
                         f30
                         f29
                         f28
                         f27
                         f26
                         f25
                         f24
                         f23
                         f22
                         f21
                         f20
                         f19
                         f18
                         f17
                         f16
                         f15
                         f14
                         f13
                         f12
                         f11

       0.03%  tchain_edit  tchain_edit       [.] f42
       0.01%  tchain_edit  tchain_edit       [.] f41
       0.00%  tchain_edit  tchain_edit       [.] f31
       0.00%  tchain_edit  ld-2.29.so        [.] _dl_relocate_object
       0.00%  tchain_edit  ld-2.29.so        [.] memmove
       0.00%  tchain_edit  [unknown]         [k] 0xffffffff93a00b17

After:

  $ perf report --stitch-lbr --no-children --stdio
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 6K of event 'cycles:u'
  # Event count (approx.): 6459496645
  #
  # Overhead  Command      Shared Object     Symbol
  # ........  ...........  ................  ........................
  #
      99.97%  tchain_edit  tchain_edit       [.] f43
              |
               --99.93%--f43
                         f42
                         f41
                         f40
                         f39
                         f38
                         f37
                         f36
                         f35
                         f34
                         f33
                         f32
                         f31
                         f30
                         f29
                         f28
                         f27
                         f26
                         f25
                         f24
                         f23
                         f22
                         f21
                         f20
                         f19
                         f18
                         f17
                         f16
                         f15
                         f14
                         f13
                         f12
                         f11
                         f10
                         f9
                         f8
                         f7
                         f6
                         f5
                         f4
                         f3
                         f2
                         f1
                         main
                         __libc_start_main

       0.02%  tchain_edit  [unknown]         [k] 0xffffffff93a00b17
       0.01%  tchain_edit  tchain_edit       [.] f31
       0.00%  tchain_edit  ld-2.29.so        [.] _dl_important_hwcaps

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/20200319202517.23423-14-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-04-18 09:05:01 -03:00
..
android.txt
asciidoc.conf perf docs: Allow man page date to be specified 2019-09-27 09:26:14 -03:00
asciidoctor-extensions.rb perf Documentation: Support for asciidoctor 2018-04-26 13:47:10 -03:00
build-xed.txt perf script: Add --insn-trace for instruction decoding 2018-10-24 15:29:50 -03:00
Build.txt perf tools: Add doc about how to build perf with Asan and UBSan 2019-03-19 16:52:04 -03:00
callchain-overhead-calculation.txt
db-export.txt perf db-export: Add brief documentation 2019-06-05 09:47:57 -03:00
examples.txt
intel-bts.txt
intel-pt.txt perf intel-pt: Update intel-pt.txt file with new location of the documentation 2020-03-11 11:00:33 -03:00
itrace.txt perf auxtrace: Add an option to synthesize callchains for regular events 2020-04-16 12:19:15 -03:00
jit-interface.txt
jitdump-specification.txt perf docs: Correct and clarify jitdump spec 2019-09-30 17:29:51 -03:00
Makefile perf doc: allow ASCIIDOC_EXTRA to be an argument 2020-04-18 09:05:00 -03:00
manpage-1.72.xsl
manpage-base.xsl
manpage-bold-literal.xsl
manpage-normal.xsl
manpage-suppress-sp.xsl
perf-annotate.txt perf tools: Support --prefix/--prefix-strip 2020-01-14 12:02:19 -03:00
perf-archive.txt
perf-bench.txt perf bench: Add event synthesis benchmark 2020-04-16 12:19:12 -03:00
perf-buildid-cache.txt perf buildid-cache: Support --purge-all option 2018-04-26 09:30:26 -03:00
perf-buildid-list.txt
perf-c2c.txt perf mem/c2c: Fix perf_mem_events to support powerpc 2019-02-04 11:32:14 -03:00
perf-config.txt perf callchain: Update docs regarding kernel/user space unwinding 2020-03-25 16:13:21 -03:00
perf-data.txt perf tools: Correct title markers for asciidoctor 2018-03-07 10:26:32 -03:00
perf-diff.txt perf diff: Report noisy for cycles diff 2019-10-11 10:57:00 -03:00
perf-evlist.txt perf evlist: Document missing --force option 2017-11-16 14:50:07 -03:00
perf-ftrace.txt perf tools: Correct title markers for asciidoctor 2018-03-07 10:26:32 -03:00
perf-help.txt
perf-inject.txt perf intel-pt: Add Intel PT man page references 2020-03-11 11:00:09 -03:00
perf-intel-pt.txt perf intel-pt: Add Intel PT man page references 2020-03-11 11:00:09 -03:00
perf-kallsyms.txt perf tools: Correct title markers for asciidoctor 2018-03-07 10:26:32 -03:00
perf-kmem.txt perf kmem: Document a missing option & an argument 2018-02-16 14:55:42 -03:00
perf-kvm.txt perf kvm: Clarify the 'perf kvm' -i and -o command line options 2019-12-02 15:38:59 -03:00
perf-list.txt perf parser: Add support to specify rXXX event with pmu 2020-04-18 09:05:00 -03:00
perf-lock.txt perf lock: Document missing options 2017-11-16 14:50:04 -03:00
perf-mem.txt perf mem/c2c: Fix perf_mem_events to support powerpc 2019-02-04 11:32:14 -03:00
perf-probe.txt perf-probe: Add user memory access attribute support 2019-05-25 23:04:42 -04:00
perf-record.txt perf record: Add --all-cgroups option 2020-04-03 09:37:55 -03:00
perf-report.txt perf report: Add option to enable the LBR stitching approach 2020-04-18 09:05:01 -03:00
perf-sched.txt perf sched timehist: Add support for filtering on CPU 2020-01-06 11:46:09 -03:00
perf-script-perl.txt perf tools: Correct title markers for asciidoctor 2018-03-07 10:26:32 -03:00
perf-script-python.txt perf script python: Add dict fields introduction to Documentation 2018-06-06 15:40:10 -03:00
perf-script.txt perf script: add -S/--symbols documentation 2020-04-03 09:37:56 -03:00
perf-stat.txt perf stat: Show percore counts in per CPU output 2020-03-04 10:34:09 -03:00
perf-test.txt
perf-timechart.txt perf timechart: Document missing --force option 2017-11-16 14:50:06 -03:00
perf-top.txt perf top: Support --group-sort-idx to change the sort order 2020-04-03 09:37:55 -03:00
perf-trace.txt perf trace: Introduce --errno-summary 2019-10-15 13:03:49 -03:00
perf-version.txt perf version: Add man page 2018-04-02 13:52:23 -03:00
perf.data-directory-format.txt perf record: Put a copy of kcore into the perf.data directory 2019-11-06 15:43:05 -03:00
perf.data-file-format.txt perf header: Support CPU PMU capabilities 2020-04-18 09:05:00 -03:00
perf.txt perf tool: Provide an option to print perf_event_open args and return value 2019-11-12 08:32:27 -03:00
perfconfig.example
tips.txt perf tools: Fix typos / broken sentences 2019-07-02 16:08:16 -03:00