Re: [PATCH v3 4/5] perf/record: add documentation for sampling skid ip

Andi Kleen
2017-11-08T20:56:50Z

> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> index 5a626ef666c2..3b156fa03c99 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -57,6 +57,14 @@ OPTIONS
> FP mode, "dwarf" for DWARF mode, "lbr" for LBR mode and
> "no" for disable callgraph.
> - 'stack-size': user stack size for dwarf mode
> + - 'skid_ip' : boolean, captures the unmodified interrupt instruction pointer
> + (IP) in each sample. Usually with event-based sampling, the IP
> + has skid and rarely point to the instruction which caused the
> + event to overflow. On some architectures, the hardware can eliminate
> + the skid and perf_events returns it as the IP with precise sampling is
> + enabled. But for certain measurements, it may be useful to have both
> + the correct and skid ip. This option enable capturing the skid ip in
> + additional to the corrected ip. Default is: false

Actually in the scanner you use 'skid-ip' (with minus). Documentation should at least match
the scanner.

_ is usually safer than -

-Andi