Using build-ids in perf tools was Re: [PATCH -tip perf/probes 00/10] x86 insn decoder bugfixes

[Arnaldo Carvalho de Melo]

Em Tue, Nov 03, 2009 at 08:24:39AM +0100, Ingo Molnar escreveu:
> * Roland McGrath <roland@redhat.com> wrote:
> > As Frank mentioned, the kernel's and modules' allocated ELF notes (and 
> > thus build IDs) are already exposed in /sys.  Tools like "eu-unstrip 
> > -nk" use this information today.
> 
> Ah, i didnt realize we link with --build-id already, unconditonally, 
> since v2.6.23 (if ld supports it):
> 
>  | From 18991197b4b588255ccabf472ebc84db7b66a19c Mon Sep 17 00:00:00 2001
>  | Subject: [PATCH] Use --build-id ld option
> 
> So we have an SHA1 build-id already on the vmlinux and on modules, and 
> it's exposed in /sys/*/*/notes. Just have to make use of it in 
> tools/perf too.

I wasn't aware this was done upstream, ass-umed that it was only on
kernel specfiles, will cook up a patch for consideration.

- Arnaldo