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

From: Hou Pengyang
Date: Mon Jun 22 2015 - 11:22:57 EST

On 2015/6/19 18:42, Ingo Molnar wrote:

* 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

I think it not difficult to generate such MMAP event, just like :

0 435090424309600 0x3e0 [0x68]: PERF_RECORD_MMAP2 788/788:[0x7f946c0000(0x4000) @ 0x7f946c0000 00:00 0 0]: ---p //anon

But for symbol parsing, this is not enough. For such mmap area, perf
doesn't know the path of '.so/.o', which is necessarcy for symbol-
parsing. So we need to tell perf the relationship between the .so file and the mmap range explicitly.


The user should not be required to know about such details!


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