Messages in this thread | | | Date | Mon, 18 Feb 2019 00:22:46 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH] perf: update perf.data file format documentation |
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On Fri, Feb 15, 2019 at 07:28:23PM +0100, Jonas Rabenstein wrote: > I found that the documentation of the flags section is some how > different from the actual format used and expected by the perf > tools. In this patch the according section of the file format > documentation is updated to conform to the expectations of the > perf tool suite. > > Signed-off-by: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de> > --- > .../perf/Documentation/perf.data-file-format.txt | 15 ++++++--------- > 1 file changed, 6 insertions(+), 9 deletions(-) > > diff --git a/tools/perf/Documentation/perf.data-file-format.txt b/tools/perf/Documentation/perf.data-file-format.txt > index dfb218feaad9..6ea199f28330 100644 > --- a/tools/perf/Documentation/perf.data-file-format.txt > +++ b/tools/perf/Documentation/perf.data-file-format.txt > @@ -43,13 +43,10 @@ struct perf_file_section { > > Flags section: > > -The header is followed by different optional headers, described by the bits set > -in flags. Only headers for which the bit is set are included. Each header > -consists of a perf_file_section located after the initial header. > -The respective perf_file_section points to the data of the additional > -header and defines its size. > - > -Some headers consist of strings, which are defined like this: > +The Flags section is placed directly after the data section and consists of a > +variable amount of information described by the flags-bitset in the perf_header. > +A lot of the headers in the Flags section are simple strings and are represented > +like this:
some how I find this more confusing.. please describe what's actualy wrong with the current wording
> > struct perf_header_string { > uint32_t len; > @@ -82,7 +79,7 @@ assigned by the linker to an executable. > struct build_id_event { > struct perf_event_header header; > pid_t pid; > - uint8_t build_id[24]; > + uint8_t build_id[PERF_ALIGN(24, sizeof(u64))];
isn't that always 24? I guess u meant:
build_id[PERF_ALIGN(20, sizeof(u64))];
> char filename[header.size - offsetof(struct build_id_event, filename)]; > }; > > @@ -131,7 +128,7 @@ An uint64_t with the total memory in bytes. > > HEADER_CMDLINE = 11, > > -A perf_header_string with the perf command line used to collect the data. > +A perf_header_string_list with the perf arg-vector used to collect the data.
nice catch
thanks, jirka
> > HEADER_EVENT_DESC = 12, > > -- > 2.17.1 >
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