[tip:perf/core] perf report: Amend documentation about max_stack and synthesized callchains

From: tip-bot for Adrian Hunter
Date: Thu Oct 01 2015 - 03:11:19 EST


Commit-ID: 40862a7b793945c7080d1566ca3dc6249f3c6354
Gitweb: http://git.kernel.org/tip/40862a7b793945c7080d1566ca3dc6249f3c6354
Author: Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate: Tue, 29 Sep 2015 11:52:37 +0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 30 Sep 2015 18:34:26 -0300

perf report: Amend documentation about max_stack and synthesized callchains

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@xxxxxxxxxx>
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/560A5155.4060105@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
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 b941d5e..ce49903 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

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