Re: [RFC 0/5] perf tools: Minimalistic build without libelf dependency

From: Namhyung Kim
Date: Mon May 14 2012 - 20:42:04 EST


On Mon, 14 May 2012 11:22:07 +0200, Ingo Molnar wrote:
> * Namhyung Kim <> wrote:
>> Hi,
>> NOTE: This is a RFC patchset and it contains a lot of rough edges
>> and ugly codes.
>> Current build procedure of perf tools requires a couple of external
>> libraries. Although most of them are optional, elfutils' libelf is
>> mandatory for resolving symbols and build-id of the binaries being
>> profiled. For some reason, it makes embedded guys' life harder who
>> want to build and run perf tools on their boards.
> Yeah, and this is a very useful patchset from that perspective.

Glad to hear that :).

>> This patch set tries to fix the problem by letting the perf could
>> be built without libelf. The initial intent was just providing
>> perf record command to gather performance events interested on the
>> system and copies the data to development box to be used by perf
>> report for analysis.
>> However it's changed to have most of perf commands as is because
>> perf can resolve kernel symbols without libelf and many of perf
>> commands deal (mostly) with kernel events - so no need to restrict
>> capability of perf tools. Therefore, the end result is not so
>> minimalistic in fact and only thing it cannot do is "perf probe".
>> And then I realized that the perf record needs to know about the
>> build-id's anyway :(. So I implemented a poor man's version of elf
>> parser only for parsing the build-id info.
>> To build a minimal perf tools, pass MINIMAL=1 to make. The perf
>> report will not display symbol names:
> Could we make this automatic when the required elf libraries are
> not present?

Yes, I think it's doable.

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