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Groups > linux.kernel > #1236816

[PATCH 04/16] perf report: Amend documentation about max_stack and synthesized callchains

From Arnaldo Carvalho de Melo <acme@kernel.org>
Newsgroups linux.kernel
Subject [PATCH 04/16] perf report: Amend documentation about max_stack and synthesized callchains
Date 2015-10-01 00:00 +0200
Message-ID <qexzR-LW-35@gated-at.bofh.it> (permalink)
References <qexzQ-LW-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: Adrian Hunter <adrian.hunter@intel.com>

The --max_stack option was added as an optimization to reduce processing time,
so people specifying --max-stack might get a increased processing time if
combined with synthesized callchains, but otherwise no real harm.

A warning about setting both --max_stack and the synthesized callchains max
depth seems like overkill.  Amend the documentation.

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/560A5155.4060105@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Documentation/perf-report.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index b941d5e07e28..ce499035e6d8 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -205,6 +205,8 @@ OPTIONS
 	beyond the specified depth will be ignored. This is a trade-off
 	between information loss and faster processing especially for
 	workloads that can have a very long callchain stack.
+	Note that when using the --itrace option the synthesized callchain size
+	will override this value if the synthesized callchain size is bigger.
 
 	Default: 127
 
-- 
2.1.0

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Thread

[GIT PULL 00/16] perf/core improvements and fixes Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-01 00:00 +0200
  [PATCH 15/16] perf list: Remove blank lines, headers when piping output Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-01 00:00 +0200
  [PATCH 12/16] perf probe: Show correct source lines of probes on kmodules Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-01 00:00 +0200
  [PATCH 16/16] perf tools: By default use the most precise "cycles" hw counter available Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-01 00:00 +0200
  [PATCH 02/16] perf tools: Fix shadowed declaration in parse-events.c Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-01 00:00 +0200
  [PATCH 09/16] tools lib symbol: Introduce kallsyms2elf_type Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-01 00:00 +0200
  [PATCH 04/16] perf report: Amend documentation about max_stack and synthesized callchains Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-01 00:00 +0200
  [PATCH 03/16] perf maps: Introduce maps__find_symbol_by_name() Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-01 00:00 +0200
  [PATCH 01/16] tools: Fix shadowed declaration in err.h Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-01 00:00 +0200
  [PATCH 07/16] perf machine: Add method for common kernel_map(FUNCTION) operation Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-10-01 00:10 +0200
  Re: [GIT PULL 00/16] perf/core improvements and fixes Ingo Molnar <mingo@kernel.org> - 2015-10-01 09:10 +0200

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