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Using build-ids in perf tools was Re: [PATCH -tip perf/probes 00/10] x86 insn decoder bugfixes
- From: Arnaldo Carvalho de Melo <acme at infradead dot org>
- To: Ingo Molnar <mingo at elte dot hu>
- Cc: Roland McGrath <roland at redhat dot com>, Masami Hiramatsu <mhiramat at redhat dot com>, Frédéric Weisbecker <fweisbec at gmail dot com>, lkml <linux-kernel at vger dot kernel dot org>, Steven Rostedt <rostedt at goodmis dot org>, Jim Keniston <jkenisto at us dot ibm dot com>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Christoph Hellwig <hch at infradead dot org>, "Frank Ch. Eigler" <fche at redhat dot com>, "H. Peter Anvin" <hpa at zytor dot com>, Jason Baron <jbaron at redhat dot com>, "K.Prasad" <prasad at linux dot vnet dot ibm dot com>, Peter Zijlstra <peterz at infradead dot org>, Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>, systemtap <systemtap at sources dot redhat dot com>, DLE <dle-develop at lists dot sourceforge dot net>
- Date: Tue, 3 Nov 2009 10:35:18 -0200
- Subject: Using build-ids in perf tools was Re: [PATCH -tip perf/probes 00/10] x86 insn decoder bugfixes
- References: <20091027204156.30545.96425.stgit@harusame> <20091029085348.GD26970@elte.hu> <20091029191801.CADC3538@magilla.sf.frob.com> <20091103072439.GA19928@elte.hu>
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