[patch] perf_event_open.2: PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT

[patch] perf_event_open.2: PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT

[Vince Weaver]

Linux 4.2 reserved a new bit from the misc field in the perf_event_open
mmap sample buffer:
PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT

Despite being reserved in the public include/uapi/linux/perf_event.h
header file, this bit is never set by the kernel, rather it is used
internally by the userspace "perf" utility to indicate that when
attempting to parse all of the /proc/xxx/maps files for the sample
it ended up taking too long so the scan was aborted.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>

diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index fa8b1bd..59ad289 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -1822,6 +1822,14 @@ See also
 .BR PERF_RECORD_MISC_EXT_RESERVED " (since Linux 2.6.35)"
 .\" commit 1676b8a077c352085d52578fb4f29350b58b6e74
 This indicates there is extended data available (currently not used).
+.TP
+.B PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT
+.\" commit 930e6fcd2bcce9bcd9d4aa7e755678d33f3fe6f4
+This bit is not set by the kernel.
+It is reserved for the userspace perf utility to indicate that
+.I /proc/xxx/maps
+parsing was taking too long and stopped and thus the mmap
+records may be truncated.
 .RE
 .TP
 .I type

Re: [patch] perf_event_open.2: PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT

[Michael Kerrisk (man-pages)]

Hi Vince,

On 10/17/2016 04:50 PM, Vince Weaver wrote:
> 
> Linux 4.2 reserved a new bit from the misc field in the perf_event_open
> mmap sample buffer:
> PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT
> 
> Despite being reserved in the public include/uapi/linux/perf_event.h
> header file, this bit is never set by the kernel, rather it is used
> internally by the userspace "perf" utility to indicate that when
> attempting to parse all of the /proc/xxx/maps files for the sample
> it ended up taking too long so the scan was aborted.
> 
> Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>

Thanks. Applied!

Cheers,

Michael


> diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
> index fa8b1bd..59ad289 100644
> --- a/man2/perf_event_open.2
> +++ b/man2/perf_event_open.2
> @@ -1822,6 +1822,14 @@ See also
>  .BR PERF_RECORD_MISC_EXT_RESERVED " (since Linux 2.6.35)"
>  .\" commit 1676b8a077c352085d52578fb4f29350b58b6e74
>  This indicates there is extended data available (currently not used).
> +.TP
> +.B PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT
> +.\" commit 930e6fcd2bcce9bcd9d4aa7e755678d33f3fe6f4
> +This bit is not set by the kernel.
> +It is reserved for the userspace perf utility to indicate that
> +.I /proc/xxx/maps
> +parsing was taking too long and stopped and thus the mmap
> +records may be truncated.
>  .RE
>  .TP
>  .I type
> 


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