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

From: Jiri Olsa
Date: Tue Oct 15 2013 - 08:23:20 EST


On Tue, Oct 15, 2013 at 09:25:40AM +0200, Ingo Molnar wrote:
>
> * Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> > > 3)
> > >
> > > The rec->bytes_at_mmap_start field feels a bit weird. If I read the code
> > > correctly, in every 'perf record' invocation, rec->bytes_written starts at
> > > 0 - i.e. we don't have repeat invocations of cmd_record().
> >
> > rec->bytes_written is updated when it writes to the output file for
> > synthesizing COMM/MMAP events (this mmap output is not used at that
> > time).
>
> Btw., while looking into it, I think advance_output() needlessly
> obfuscates as well:
>
> static void advance_output(struct perf_record *rec, size_t size)
> {
> rec->bytes_written += size;
> }
>
> that code should just be written open coded.
>
> So I think all this needs a few good rounds of cleanups, before we can
> complicate it with a new feature. (the cleanups can be on top of the
> feature, if they go in at the same time.)

I sent some file code cleanup week ago, I'll rebase
and resend it soon:
http://marc.info/?l=linux-kernel&m=138113836428425&w=2

it's mostly about centralizing the code into file
object.. got no comments so far

jirka
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