Re: [PATCH v6 6/6] perf util: use correct IP mapping to find srcline for hist entry
From: Milian Wolff
Date: Thu Oct 19 2017 - 06:54:27 EST
On Mittwoch, 18. Oktober 2017 20:53:50 CEST 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@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Yao Jin <yao.jin@xxxxxxxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Signed-off-by: Milian Wolff <milian.wolff@xxxxxxxx>
>
> 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);
> }
Sorry, this patch was declined by Nahmyung before, please discard it - I
forgot to do that before resending v6.
Bye
--
Milian Wolff | milian.wolff@xxxxxxxx | Senior Software Engineer
KDAB (Deutschland) GmbH&Co KG, a KDAB Group company
Tel: +49-30-521325470
KDAB - The Qt Experts