Re: [tip:perf/core] perf: Update perf_event_type documentation

From: Vince Weaver
Date: Fri Sep 13 2013 - 17:30:19 EST


On Tue, 23 Jul 2013, tip-bot for Peter Zijlstra wrote:

> Commit-ID: a5cdd40c9877e9aba704c020fd65d26b5cfecf18
> Gitweb: http://git.kernel.org/tip/a5cdd40c9877e9aba704c020fd65d26b5cfecf18
> Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> AuthorDate: Tue, 16 Jul 2013 17:09:07 +0200
> Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> CommitDate: Tue, 23 Jul 2013 12:17:08 +0200
>
> perf: Update perf_event_type documentation
>
> Due to a discussion with Adrian I had a good look at the perf_event_type record
> layout and found the documentation to be somewhat unclear.
>
> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Link: http://lkml.kernel.org/r/20130716150907.GL23818@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
> ---
> include/uapi/linux/perf_event.h | 18 +++++++++++++++++-
> kernel/events/core.c | 31 ++++++++++++++++---------------
> 2 files changed, 33 insertions(+), 16 deletions(-)
>
> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> index 0b1df41..00d8274 100644
> --- a/include/uapi/linux/perf_event.h
> +++ b/include/uapi/linux/perf_event.h
> @@ -478,6 +478,16 @@ enum perf_event_type {
> * file will be supported by older perf tools, with these new optional
> * fields being ignored.
> *
> + * struct sample_id {
> + * { u32 pid, tid; } && PERF_SAMPLE_TID
> + * { u64 time; } && PERF_SAMPLE_TIME
> + * { u64 id; } && PERF_SAMPLE_ID
> + * { u64 stream_id;} && PERF_SAMPLE_STREAM_ID
> + * { u32 cpu, res; } && PERF_SAMPLE_CPU
> + * } && perf_event_attr::sample_id_all
> + */
> +
> + /*
> * The MMAP events record the PROT_EXEC mappings so that we can
> * correlate userspace IPs to code. They have the following structure:
> *
> @@ -498,6 +508,7 @@ enum perf_event_type {
> * struct perf_event_header header;
> * u64 id;
> * u64 lost;
> + * struct sample_id sample_id;
> * };
> */
> PERF_RECORD_LOST = 2,

So in Adrian Hunter's posted patches the PERF_RECORD_MMAP documentation
is also patched like all the others, with

struct sample_id sample_id;

But in this tip message (and in the current linus-git kernel) somehow the
PERF_RECORD_MMAP line of the patch was dropped.

Was that intentional?

I'm trying to document this mess in the manpage, not fun.

Vince
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