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Date: Fri, 20 Oct 2017 14:15:33 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: Milian Wolff <milian.wolff@...b.com>
Cc: acme@...nel.org, jolsa@...nel.org, Linux-kernel@...r.kernel.org,
linux-perf-users@...r.kernel.org,
Arnaldo Carvalho de Melo <acme@...hat.com>,
Yao Jin <yao.jin@...ux.intel.com>,
Jiri Olsa <jolsa@...hat.com>, kernel-team@....com
Subject: Re: [PATCH v6 6/6] perf util: use correct IP mapping to find srcline
for hist entry
Hi Milian,
On Thu, Oct 19, 2017 at 12:54:18PM +0200, Milian Wolff wrote:
> 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@...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);
> > }
>
> Sorry, this patch was declined by Nahmyung before, please discard it - I
> forgot to do that before resending v6.
I looked into it and found a bug handling cumulative (children)
entries. For chilren entries that has no self period, the al->addr
(so he->ip) ends up having an doubly-mapped address.
It seems to be there from the beginning but only affects entries that
have no srclines - finding srcline itself is done using a different
address but it will show the invalid address if no srcline was found.
I think we should fix the commit c7405d85d7a3 ("perf tools: Update
cpumode for each cumulative entry").
Could you please test the following patch works for you?
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 35a920f09503..d18cdcc8d132 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -1074,10 +1074,7 @@ int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *
{
al->map = node->map;
al->sym = node->sym;
- if (node->map)
- al->addr = node->map->map_ip(node->map, node->ip);
- else
- al->addr = node->ip;
+ al->addr = node->ip;
if (al->sym == NULL) {
if (hide_unresolved)
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