Re: [PATCH 1/4] perf, tools: Add support for prepending LBRs to thecallstack

From: Arnaldo Carvalho de Melo
Date: Sat Jan 11 2014 - 14:23:56 EST


Em Sat, Jan 11, 2014 at 06:58:16PM +0100, Andi Kleen escreveu:
> On Sat, Jan 11, 2014 at 04:36:14PM +0100, Jiri Olsa wrote:
> > On Fri, Jan 10, 2014 at 04:32:03AM -0800, Andi Kleen wrote:
> > > From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> > >
> > > I never found the default LBR display mode which generates histograms
> > > of individual branches particularly useful.
> > >
> > > This implements an alternative mode that creates histograms over complete
> > > branch traces, instead of individual branches, similar to how normal
> > > callgraphs are handled. This is done by putting it in
> > > front of the normal callgraph and then using the normal callgraph
> > > histogram infrastructure to unify them.
> > >
> > > This way in complex functions we can understand the control flow
> > > that lead to a particular sample.
> > >
> > > The default output is unchanged.
> > >
> > > This is only implemented in perf report, no change to record
> > > or anywhere else.
> > >
> > > This adds the basic code to report:
> > > - add a new "branch" option to the -g option parser to enable this mode
> > > - when the flag is set include the LBR into the callstack in machine.c.
> > > The rest of the history code is unchanged and doesn't know the difference
> > > between LBR entry and normal call entry.
> >
> > sounds like nice idea, but I could not get the patchset applied
> > on acme's perf/core
>
> It was on Linus master.
>
> I tried to rebase on perf/core, but it seems to be totally broken by
> itself. All the config tests fail on my opensuse system.
>
> Arnaldo?

Oops, checking on some systems...

> Auto-detecting system features:
> ... backtrace: [ OFF ]
> ... dwarf: [ OFF ]
> ... fortify-source: [ OFF ]
> ... glibc: [ OFF ]
> ... gtk2: [ OFF ]
> ... gtk2-infobar: [ OFF ]
> ... libaudit: [ OFF ]
> ... libbfd: [ OFF ]
> ... libelf: [ OFF ]
> ... libelf-getphdrnum: [ OFF ]
> ... libelf-mmap: [ OFF ]
> ... libnuma: [ OFF ]
> ... libperl: [ OFF ]
> ... libpython: [ OFF ]
> ... libpython-version: [ OFF ]
> ... libslang: [ OFF ]
> ... libunwind: [ OFF ]
> ... on-exit: [ OFF ]
> ... stackprotector-all: [ OFF ]
> ... timerfd: [ OFF ]
>
> config/Makefile:282: *** No gnu/libc-version.h found, please install
> glibc-dev[el]/glibc-static. Stop.
> make: *** [all] Error 2
>
> -Andi
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