Re: [PATCH] perf record: mmap output file - v2

From: Namhyung Kim
Date: Tue Oct 15 2013 - 04:17:50 EST


On Tue, 15 Oct 2013 09:25:40 +0200, Ingo Molnar wrote:
> * Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>> No, st_size is bigger than rec->bytes_written due to the
>> perf_file_header which is written without updating rec->bytes_written.
>
> Since all this is code that executes once during __cmd_record(), is this
> all about the header writeout?
>
> That is what confused me about the stat() call and that's messy really: we
> are the ones who write the file header, we have a very good idea about how
> many bytes we wrote to the file! It should be entirely unnecessary to lose
> that information and then execute a system call to recover that
> information...

Right, I think session->header.data_offset has the info already.

Thanks,
Namhyung
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