Re: [RFC] perf report: introduce --map-anon-mem for anon-executable-memory symbols parsing

From: Arnaldo Carvalho de Melo
Date: Fri Jun 19 2015 - 16:10:35 EST


Em Fri, Jun 19, 2015 at 12:42:14PM +0200, Ingo Molnar escreveu:
> * Wangnan (F) <wangnan0@xxxxxxxxxx> wrote:
>
> > On 2015/6/18 22:01, Hou Pengyang wrote:
> > >This patch introduces a --map-anon-mem argument to perf report to deal
> > >with anon-executable-memory symbol parsing.
> >
> > --map-anon-mem is not a good name. The user defined map area list
> > introduced in this patch can be used on not only anon mapping but
> > also file mapping.
>
> Yeah, so quirky options generally suck and only 0.01% of the users will use it.
> It's in a way worse than not having this code, because we'll have to maintain it,
> but it won't be used.
>
> Is there a way to auto-detect 'executable anon mappings' (perhaps by generating an
> MMAP event with some extra bit set, or a new MMAP event?) so that it's all
> seemless?
>
> The user should not be required to know about such details!

Also I think we shouldn't have two maps instances, i.e. if one wants to
insert some "map files", i.e. details about a map on a file, csv or any
other format (JSON anyone? :-)), or like he did, on the command line,
then it should be added to the existing per thread tree of maps, i.e.
would be useful for some super specialized corner case but wouldn't
impact the common case, i.e. no try this tree of maps, if it is not
there, then try the other, that everybody else uses, etc.

- Arnaldo
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