linux-kernel - Re: [patch] perf_event_open.2: PERF_RECORD_LOST

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Date:   Mon, 17 Oct 2016 08:46:10 +0200
From:   "Michael Kerrisk (man-pages)" <mtk.manpages@...il.com>
To:     Vince Weaver <vincent.weaver@...ne.edu>
Cc:     mtk.manpages@...il.com, linux-man@...r.kernel.org,
        linux-kernel@...r.kernel.org, Kan Liang <kan.liang@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Stephane Eranian <eranian@...il.com>
Subject: Re: [patch] perf_event_open.2: PERF_RECORD_LOST_SAMPLES record type

Hello Vince,

On 10/16/2016 04:02 AM, Vince Weaver wrote:
> 
> Linux 4.2 added a new record type: PERF_RECORD_LOST_SAMPLES
> It is generated when hardware samples (currently only Intel PEBS)
> are lost.

Thanks! Applied!

Cheers,

Michael


 
> Signed-off-by: Vince Weaver <vincent.weaver@...ne.edu>
> 
> diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
> index 9f33122..a47df2d 100644
> --- a/man2/perf_event_open.2
> +++ b/man2/perf_event_open.2
> @@ -2551,6 +2551,25 @@ process ID of the thread starting an instruction trace.
>  .I tid
>  thread ID of the thread starting an instruction trace.
>  .RE
> +.TP
> +.BR PERF_RECORD_LOST_SAMPLES " (since Linux 4.2)"
> +\" f38b0dbb491a6987e198aa6b428db8692a6480f8
> +When using hardware sampling (such as Intel PEBS) this record
> +indicates some number of samples may have been lost.
> +
> +.in +4n
> +.nf
> +struct {
> +    struct perf_event_header header;
> +    u64 lost;
> +    struct sample_id sample_id;
> +};
> +.fi
> +.RS
> +.TP
> +.I lost
> +the number of potentially lost samples.
> +.RE
>  .RE
>  .SS Overflow handling
>  Events can be set to notify when a threshold is crossed,
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/