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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20171108205643.GB8522@tassilo.jf.intel.com>
Date:   Wed, 8 Nov 2017 12:56:43 -0800
From:   Andi Kleen <ak@...ux.intel.com>
To:     Stephane Eranian <eranian@...gle.com>
Cc:     linux-kernel@...r.kernel.org, acme@...hat.com,
        peterz@...radead.org, mingo@...e.hu, kan.liang@...el.com,
        jolsa@...hat.com
Subject: Re: [PATCH v3 4/5] perf/record: add documentation for sampling skid
 ip

> 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