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Re: [PATCH 1/8] perf tools: Omit DWARF judgement when recording dwarf callchain

From Arnaldo Carvalho de Melo <acme@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH 1/8] perf tools: Omit DWARF judgement when recording dwarf callchain
Date 2016-05-09 18:20 +0200
Message-ID <rwW4y-Lb-13@gated-at.bofh.it> (permalink)
References <rvJVM-2eU-17@gated-at.bofh.it> <rvJVM-2eU-21@gated-at.bofh.it> <rwePT-6s5-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Em Sat, May 07, 2016 at 08:03:46PM +0200, Jiri Olsa escreveu:
> On Fri, May 06, 2016 at 08:59:07AM +0000, He Kuang wrote:
> > There's no need for dwarf support when perf recording with callchain.
> > 
> > Signed-off-by: He Kuang <hekuang@huawei.com>
> 
> Acked-by: Jiri Olsa <jolsa@kernel.org>

Ok, due to your Ack I went on to read the code and indeed, with this
changeset description:

"There is no need to check for DWARF unwinding support when using the
'dwarf' callchain record method, as this will only ask the kernel to
collect stack dumps for later DWARF CFI processing, which can be done
in another machine, where the support for DWARF unwinding need to be
present."

Thanks,

- Arnaldo
 
> thanks,
> jirka
> 
> > ---
> >  tools/perf/util/util.c | 2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
> > index b7766c5..e5ebfd4 100644
> > --- a/tools/perf/util/util.c
> > +++ b/tools/perf/util/util.c
> > @@ -471,7 +471,6 @@ int parse_callchain_record(const char *arg, struct callchain_param *param)
> >  				       "needed for --call-graph fp\n");
> >  			break;
> >  
> > -#ifdef HAVE_DWARF_UNWIND_SUPPORT
> >  		/* Dwarf style */
> >  		} else if (!strncmp(name, "dwarf", sizeof("dwarf"))) {
> >  			const unsigned long default_stack_dump_size = 8192;
> > @@ -487,7 +486,6 @@ int parse_callchain_record(const char *arg, struct callchain_param *param)
> >  				ret = get_stack_size(tok, &size);
> >  				param->dump_size = size;
> >  			}
> > -#endif /* HAVE_DWARF_UNWIND_SUPPORT */
> >  		} else if (!strncmp(name, "lbr", sizeof("lbr"))) {
> >  			if (!strtok_r(NULL, ",", &saveptr)) {
> >  				param->record_mode = CALLCHAIN_LBR;
> > -- 
> > 1.8.5.2
> > 

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Thread

[PATCH 1/8] perf tools: Omit DWARF judgement when recording dwarf callchain He Kuang <hekuang@huawei.com> - 2016-05-06 11:10 +0200
  Re: [PATCH 1/8] perf tools: Omit DWARF judgement when recording  dwarf callchain Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-05-06 13:50 +0200
  Re: [PATCH 1/8] perf tools: Omit DWARF judgement when recording  dwarf callchain Jiri Olsa <jolsa@redhat.com> - 2016-05-07 20:10 +0200
    Re: [PATCH 1/8] perf tools: Omit DWARF judgement when recording  dwarf callchain Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-05-09 18:20 +0200
      Re: [PATCH 1/8] perf tools: Omit DWARF judgement when recording dwarf  callchain Hekuang <hekuang@huawei.com> - 2016-05-10 03:50 +0200
  [tip:perf/core] perf callchain: Recording 'dwarf' callchains do not  need DWARF unwinding support tip-bot for He Kuang <tipbot@zytor.com> - 2016-05-10 22:40 +0200

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