Star64_linux/tools/perf/Documentation
Namhyung Kim 1a61046d0c perf intel-pt: Do not try to queue auxtrace data on pipe
[ Upstream commit aeb802f872 ]

When it processes AUXTRACE_INFO, it calls to auxtrace_queue_data() to
collect AUXTRACE data first.  That won't work with pipe since it needs
lseek() to read the scattered aux data.

  $ perf record -o- -e intel_pt// true | perf report -i- --itrace=i100
  # To display the perf.data header info, please use --header/--header-only options.
  #
  0x4118 [0xa0]: failed to process type: 70
  Error:
  failed to process sample

For the pipe mode, it can handle the aux data as it gets.  But there's
no guarantee it can get the aux data in time.  So the following warning
will be shown at the beginning:

  WARNING: Intel PT with pipe mode is not recommended.
           The output cannot relied upon.  In particular,
           time stamps and the order of events may be incorrect.

Fixes: dbd134322e ("perf intel-pt: Add support for decoding AUX area samples")
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20230131023350.1903992-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-19 17:59:59 +08:00
..
android.txt
asciidoc.conf
asciidoctor-extensions.rb
build-docdep.perl
build-xed.txt
Build.txt
callchain-overhead-calculation.txt
cat-texi.perl
db-export.txt
examples.txt
intel-bts.txt
intel-hybrid.txt
intel-pt.txt
itrace.txt
jit-interface.txt
jitdump-specification.txt
Makefile
manpage-1.72.xsl
manpage-base.xsl
manpage-bold-literal.xsl
manpage-normal.xsl
manpage-suppress-sp.xsl
perf-annotate.txt
perf-archive.txt
perf-bench.txt
perf-buildid-cache.txt
perf-buildid-list.txt
perf-c2c.txt
perf-config.txt
perf-daemon.txt
perf-data.txt
perf-diff.txt
perf-dlfilter.txt
perf-evlist.txt
perf-ftrace.txt
perf-help.txt
perf-inject.txt
perf-intel-pt.txt perf intel-pt: Do not try to queue auxtrace data on pipe 2023-04-19 17:59:59 +08:00
perf-iostat.txt
perf-kallsyms.txt
perf-kmem.txt
perf-kvm.txt
perf-list.txt
perf-lock.txt
perf-mem.txt
perf-probe.txt
perf-record.txt
perf-report.txt
perf-sched.txt
perf-script-perl.txt
perf-script-python.txt
perf-script.txt
perf-stat.txt
perf-test.txt
perf-timechart.txt
perf-top.txt
perf-trace.txt
perf-version.txt
perf.data-directory-format.txt
perf.data-file-format.txt
perf.txt
perfconfig.example
security.txt
tips.txt
topdown.txt