[tip: perf/urgent] perf kvm: Clarify the 'perf kvm' -i and -o command line options

From: tip-bot2 for Arnaldo Carvalho de Melo
Date: Wed Dec 04 2019 - 02:55:00 EST


The following commit has been merged into the perf/urgent branch of tip:

Commit-ID: 9974406884459c9301597c2c9f7def6c38099ab4
Gitweb: https://git.kernel.org/tip/9974406884459c9301597c2c9f7def6c38099ab4
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Mon, 02 Dec 2019 15:38:59 -03:00
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitterDate: Mon, 02 Dec 2019 15:38:59 -03:00

perf kvm: Clarify the 'perf kvm' -i and -o command line options

The 'perf kvm' subcommand has options that it in turn passes to other
perf subcommands such as 'report' and 'record', particularly -i and -o
end up setting the same variable that will then be used for 'record's -o
and report '-i', which ends up being confusing, leading some to think
that both -i and -o can be used with 'report'.

Improve the man page to state that -i is used with the post-processing
subcommands while -o is used just with 'record' and that to save the
output of 'report' one should simply redirect its output to a file.

Noticed while reading the https://www.linux-kvm.org/page/Perf_events
page.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Steve Dickson <steved@xxxxxxxxxx>
Cc: William Cohen <wcohen@xxxxxxxxxx>
Link: https://lkml.kernel.org/n/tip-tclbttvmgtm525fvmh85f7d9@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/Documentation/perf-kvm.txt | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Documentation/perf-kvm.txt b/tools/perf/Documentation/perf-kvm.txt
index 6a5bb2b..cf95bae 100644
--- a/tools/perf/Documentation/perf-kvm.txt
+++ b/tools/perf/Documentation/perf-kvm.txt
@@ -68,10 +68,11 @@ OPTIONS
-------
-i::
--input=<path>::
- Input file name.
+ Input file name, for the 'report', 'diff' and 'buildid-list' subcommands.
-o::
--output=<path>::
- Output file name.
+ Output file name, for the 'record' subcommand. Doesn't work with 'report',
+ just redirect the output to a file when using 'report'.
--host::
Collect host side performance profile.
--guest::