Messages in this thread | | | Date | Tue, 03 Feb 2015 10:42:33 +0200 | From | Adrian Hunter <> | Subject | Re: [PATCH 14/42] perf record: Add --index option for building index table |
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On 02/02/15 19:30, Jiri Olsa wrote: > On Mon, Feb 02, 2015 at 11:56:09PM +0900, Namhyung Kim wrote: >> Hi Jiri and Adrian, >> >> On Mon, Feb 2, 2015 at 9:13 PM, Jiri Olsa <jolsa@redhat.com> wrote: >>> On Mon, Feb 02, 2015 at 02:07:27PM +0200, Adrian Hunter wrote: >>> >>> SNIP >>> >>>>>> >>>>>> Why not make it the same as all the other data. i.e. find the start and size >>>>>> via the index? And then just lump all the data together? >>>>> >>>>> thats what I suggested >>>> >>>> No, I meant really lump it all together. i.e. perf_file_header.data.size = >>>> total data size >>>> >>>>> >>>>>> >>>>>>> I guess we could workaround that by storing the 'perf_file_header::data' >>>>>>> as the last data section. That would require to treat it the same way as >>>>>>> all other data sections, but we could keep current header layout. >>>>>> >>>>>> Would it need to be last? Logically it should precede the data that depends >>>>>> on it. >>>>> >>>>> i suggested this as a workaround for having features at the end of the file >>>>> while keeping the current perf data header >>>> >>>> Which wouldn't be necessary if you lump it all together? >>> >>> yep, that's also an option >> >> So we want a single section for the entire data area, right? >> >> I also thought about it. My concern was the holes between each data >> due to page alignment. If an old tool which doesn't know about the >> index accesses to the data file, it'd just see a event type of 0 and >> stop processing.
Please don't leave holes. Either fill them with a padding event or put the data end-to-end.
>> >> Maybe the page alignment is not necessary? > > seems ok, but how about time ordering.. every time you reach new > file data you'll hit 'out of order event' right? > > hum, maybe it's not a big deal now when it's just incrementing counter ;-) > > jirka > >
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