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Date: Thu, 12 Oct 2017 20:22:58 +0200
From: Milian Wolff <milian.wolff@...b.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: acme@...nel.org, jolsa@...nel.org,
Jin Yao <yao.jin@...ux.intel.com>,
Linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
Arnaldo Carvalho de Melo <acme@...hat.com>,
Jiri Olsa <jolsa@...hat.com>, kernel-team@....com
Subject: Re: [PATCH v5 16/16] perf util: use correct IP mapping to find srcline for hist entry
On Dienstag, 10. Oktober 2017 06:49:54 CEST Namhyung Kim wrote:
> Hi Milian,
>
> On Mon, Oct 09, 2017 at 10:33:10PM +0200, Milian Wolff wrote:
> > When inline frame resolution is disabled, a bogus srcline is obtained
> > for hist entries:
> >
> > ~~~~~
> > $ perf report -s sym,srcline --no-inline --stdio -g none
> >
> > 95.21% 0.00% [.] __libc_start_main
> >
> > __libc_start_main+18446603358170398953 95.21% 0.00% [.] _start
> >
> > _start+18446650082411225129
> > 46.67% 0.00% [.] main
> >
> > main+18446650082411225208 38.75% 0.00% [.] hypot
> >
> > hypot+18446603358164312084 23.75% 0.00%
> > [.] main
> >
> > main+18446650082411225151 20.83% 20.83% [.]
> > std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > random.h:143 18.12% 0.00% [.] main
> >
> > main+18446650082411225165 13.12%
> > 13.12% [.] std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > random.tcc:3330>
> > 4.17% 4.17% [.] __hypot_finite
> >
> > __hypot_finite+163 4.17% 4.17% [.]
> > std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > random.tcc:3333 4.17% 0.00% [.] __hypot_finite
> >
> > __hypot_finite+18446603358164312227
> > 4.17% 0.00% [.] std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > std::generate_canonical<double, 53ul, std::line
> > 2.92% 0.00% [.] std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > std::generate_canonical<double, 53ul, std::line
> > 2.50% 2.50% [.] __hypot_finite
> >
> > __hypot_finite+11 2.50% 2.50% [.] __hypot_finite
> >
> > __hypot_finite+24 2.50% 0.00% [.]
> > __hypot_finite
> >
> > __hypot_finite+18446603358164312075 2.50% 0.00% [.]
> > __hypot_finite
> >
> > __hypot_finite+18446603358164312088>
> > ~~~~~
> >
> > Note how we get very large offsets to main and cannot see any srcline
> > from one of the complex or random headers, even though the instruction
> > pointers actually lie in code inlined from there.
> >
> > This patch fixes the mapping to use map__objdump_2mem instead of
> > map__objdump_2mem in hist_entry__get_srcline. This fixes the srcline
> > values for me when inline resolution is disabled:
> >
> > ~~~~~
> > $ perf report -s sym,srcline --no-inline --stdio -g none
> >
> > 95.21% 0.00% [.] __libc_start_main
> >
> > __libc_start_main+233 95.21% 0.00% [.] _start
> >
> > _start+41 46.88% 0.00% [.] main
> >
> > complex:589 43.96% 0.00% [.] main
> >
> > random.h:185 38.75% 0.00%
> > [.] hypot
> > hypot+20 20.83%
> > 0.00% [.] std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > random.h:143 13.12% 0.00% [.]
> > std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > random.tcc:3330>
> > 4.17% 4.17% [.] __hypot_finite
> >
> > __hypot_finite+140715545239715 4.17% 4.17% [.]
> > std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > std::generate_canonical<double, 53ul, std::line
> > 4.17% 0.00% [.] __hypot_finite
> >
> > __hypot_finite+163 4.17% 0.00% [.]
> > std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > random.tcc:3333 2.92% 2.92% [.]
> > std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > std::generate_canonical<double, 53ul, std::line
> > 2.50% 2.50% [.] __hypot_finite
> >
> > __hypot_finite+140715545239563 2.50% 2.50% [.] __hypot_finite
> >
> > __hypot_finite+140715545239576 2.50%
> > 2.50% [.] std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > std::generate_canonical<double, 53ul, std::line
> > 2.50% 2.50% [.] std::generate_canonical<double, 53ul,
> > std::linear_congruential_engine<unsigned long, 16807ul, 0ul,
> > 2147483647ul> > std::generate_canonical<double, 53ul, std::line
> > 2.50% 0.00% [.] __hypot_finite
> >
> > __hypot_finite+11>
> > ~~~~~
> >
> > Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
> > Cc: Namhyung Kim <namhyung@...nel.org>
> > Cc: Yao Jin <yao.jin@...ux.intel.com>
> > Cc: Jiri Olsa <jolsa@...hat.com>
> > Signed-off-by: Milian Wolff <milian.wolff@...b.com>
> >
> > Note how most of the large offset values are now gone. Most notably,
> > we get proper srcline resolution for the random.h and complex headers.
> > ---
> >
> > tools/perf/util/sort.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
> > index 006d10a0dc96..6f3d109078a3 100644
> > --- a/tools/perf/util/sort.c
> > +++ b/tools/perf/util/sort.c
> > @@ -334,7 +334,7 @@ char *hist_entry__get_srcline(struct hist_entry *he)
> >
> > if (!map)
> >
> > return SRCLINE_UNKNOWN;
> >
> > - return get_srcline(map->dso, map__rip_2objdump(map, he->ip),
> > + return get_srcline(map->dso, map__objdump_2mem(map, he->ip),
> >
> > he->ms.sym, true, true);
>
> I'm not sure this is right. IIRC hist_entry->ip is a relative IP so
> it needs to be changed for objdump use. Maybe there's some bug on
> translating the address but it seems that the original code is
> correct. And this change breaks srcline for my test program (which is
> a PIE).
Odd, I'll have to look at that. But this is imo unrelated to the rest of the
patch series. So maybe we skip this one and apply the others. Assuming those
other patches are OK by now?
Jiri, you also reviewed it before, is there anything else missing?
Cheers
--
Milian Wolff | milian.wolff@...b.com | Senior Software Engineer
KDAB (Deutschland) GmbH&Co KG, a KDAB Group company
Tel: +49-30-521325470
KDAB - The Qt Experts
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