2016-10-16 02:03:03

by Vince Weaver

Subject: [patch] perf_event_open.2: PERF_RECORD_LOST_SAMPLES record type

Linux 4.2 added a new record type: PERF_RECORD_LOST_SAMPLES
It is generated when hardware samples (currently only Intel PEBS)
are lost.

Signed-off-by: Vince Weaver <[email protected]>

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,

2016-10-17 06:46:23

by Michael Kerrisk (man-pages)

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 <[email protected]>
>
> 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/