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From: Andi Kleen <ak@linux.intel.com>
To: Stephane Eranian <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, acme@redhat.com,
	peterz@infradead.org, mingo@elte.hu, kan.liang@intel.com,
	jolsa@redhat.com
Subject: Re: [PATCH v3 4/5] perf/record: add documentation for sampling skid ip
Date: Wed, 8 Nov 2017 12:56:43 -0800	[thread overview]
Message-ID: <20171108205643.GB8522@tassilo.jf.intel.com> (raw)
In-Reply-To: <1510127797-22483-5-git-send-email-eranian@google.com>

> 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

  reply	other threads:[~2017-11-08 20:56 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-08  7:56 [PATCH v3 0/5] perf: add support for capturing skid IP Stephane Eranian
2017-11-08  7:56 ` [PATCH v3 1/5] perf/core: add PERF_RECORD_SAMPLE_SKID_IP record type Stephane Eranian
2017-11-08  7:56 ` [PATCH v3 2/5] perf/x86: add PERF_SAMPLE_SKID_IP support for X86 PEBS Stephane Eranian
2017-11-08  7:56 ` [PATCH v3 3/5] perf/tools: add support for PERF_SAMPLE_SKID_IP Stephane Eranian
2017-11-08  7:56 ` [PATCH v3 4/5] perf/record: add documentation for sampling skid ip Stephane Eranian
2017-11-08 20:56   ` Andi Kleen [this message]
2017-11-09  3:42     ` Stephane Eranian
2017-11-08  7:56 ` [PATCH v3 5/5] perf/script: add support for " Stephane Eranian
2017-11-08 10:43   ` Jiri Olsa

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