Re: [PATCH v4 00/16] perf tool: add meta-data header support for pipe-mode

[David Carrillo-Cisneros]

On Tue, Jun 13, 2017 at 11:54 AM, Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> On Mon, Jun 12, 2017 at 09:29:16PM -0700, David Carrillo-Cisneros wrote:
>> v4: - Limit write_* functions to page_size.
>>     - Fixed bugs spotted by Jiri.
>>     - Add information about pipe-mode to some error messages.
>
> hum, looks like we have pipe report broken.. on arnaldo's perf/core branch:
>
> [jolsa@krava perf]$ ./perf record ls | ./perf report
> # To display the perf.data header info, please use --header/--header-only options.
> #
>
> ...
>
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.000 MB (null) ]
> #
> # Total Lost Samples: 0
> #
> # Samples: 10  of event 'cycles:uhH'
> # Event count (approx.): 1810081
> #
> # Overhead  Trace output
> # ........  ............
> #
>    100.00%  N/A

I saw this bug before, that time I bisected it to commit d49dadea7862
("perf tools: Make 'trace' or 'trace_fields' sort key default for
tracepoint events") from Dec 2015 but didn't have time to look further
into it ...

David