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Message-ID: <ZBQZoyJc7mhUrL8n@samus.usersys.redhat.com>
Date: Fri, 17 Mar 2023 08:41:23 +0100
From: Artem Savkov <asavkov@...hat.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
Adrian Hunter <adrian.hunter@...el.com>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
Milian Wolff <milian.wolff@...b.com>,
Masami Hiramatsu <mhiramat@...nel.org>,
Andrii Nakryiko <andrii.nakryiko@...il.com>
Subject: Re: [PATCH 0/1] perf report: append inlines to non-dwarf callchains
On Thu, Mar 16, 2023 at 02:26:18PM -0700, Namhyung Kim wrote:
> Hello,
>
> On Thu, Mar 16, 2023 at 6:36 AM Artem Savkov <asavkov@...hat.com> wrote:
> >
> > In an email to Arnaldo Andrii Nakryiko suggested that perf can get
> > information about inlined functions from dwarf when available and then
> > add it to userspace stacktraces even in framepointer or lbr mode.
> > Looking closer at perf it turned out all required bits and pieces are
> > already there and inline information can be easily added to both
> > framepointer and lbr callchains by adding an append_inlines() call to
> > add_callchain_ip().
>
> Looks great! Have you checked it with perf report -g callee ?
> I'm not sure the ordering of inlined functions is maintained
> properly. Maybe you can use --no-children too to simplify
> the output.
Thanks for the suggestion. I actually have another test program with
functions being numbered rather than (creatively) named, so it might be
easier to use it to figure out ordering. Here's the code:
======
#include <stdio.h>
#include <stdint.h>
static __attribute__((noinline)) uint32_t func5(uint32_t i)
{
return i + 10;
}
static uint32_t func4(uint32_t i)
{
return func5(i + 5);
}
static inline uint32_t func3(uint32_t i)
{
return func4(i + 4);
}
static __attribute__((noinline)) uint32_t func2(uint32_t i)
{
return func3(i + 3);
}
static uint32_t func1(uint32_t i)
{
return func2(i + 2);
}
__attribute__((noinline)) uint64_t entry(void)
{
uint64_t ret = 0;
uint32_t i = 0;
for (i = 0; i < 1000000; i++) {
ret += func1(i);
ret -= func2(i);
ret += func3(i);
ret += func4(i);
ret -= func5(i);
}
return ret;
}
int main(int argc, char **argv)
{
printf("%s\n", __func__);
return entry();
}
======
Here is the output I get with '--call-graph callee --no-children'
======
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 250 of event 'cycles:u'
# Event count (approx.): 26819859
#
# Overhead Command Shared Object Symbol
# ........ ....... .................... .....................................
#
43.58% a.out a.out [.] func5
|
|--28.93%--entry
| main
| __libc_start_call_main
|
--14.65%--func4 (inlined)
|
|--10.45%--entry
| main
| __libc_start_call_main
|
--4.20%--func3 (inlined)
entry
main
__libc_start_call_main
38.80% a.out a.out [.] entry
|
|--23.27%--func4 (inlined)
| |
| |--20.28%--func3 (inlined)
| | func2
| | main
| | __libc_start_call_main
| |
| --2.99%--entry
| main
| __libc_start_call_main
|
|--8.17%--func5
| main
| __libc_start_call_main
|
|--3.89%--func1 (inlined)
| entry
| main
| __libc_start_call_main
|
--3.48%--entry
main
__libc_start_call_main
13.07% a.out a.out [.] func2
|
---func5
main
__libc_start_call_main
1.54% a.out [unknown] [k] 0xffffffff81e011b7
1.16% a.out [unknown] [k] 0xffffffff81e00193
|
--0.57%--__mmap64 (inlined)
__mmap64 (inlined)
0.34% a.out ld-linux-x86-64.so.2 [.] __tunable_get_val
0.34% a.out ld-linux-x86-64.so.2 [.] strcmp
0.32% a.out libc.so.6 [.] strchr
0.31% a.out ld-linux-x86-64.so.2 [.] _dl_relocate_object
0.22% a.out ld-linux-x86-64.so.2 [.] _dl_init_paths
0.18% a.out ld-linux-x86-64.so.2 [.] get_common_cache_info.constprop.0
0.14% a.out ld-linux-x86-64.so.2 [.] __GI___tunables_init
#
# (Tip: Show individual samples with: perf script)
#
======
It does not seem to be out of order, or at least it is consistent with
what I get with dwarf unwinders.
>
> Thanks,
> Namhyung
>
> >
> > I used the following small program for testing:
> >
> > ======
> > #include <stdio.h>
> > #include <stdint.h>
> >
> > static __attribute__((noinline)) uint32_t func_noinline2(uint32_t i)
> > {
> > return i + 10;
> > }
> >
> > static inline uint32_t func_declared_inlined(uint32_t i)
> > {
> > return func_noinline2(i + 4);
> > }
> >
> > static __attribute__((noinline)) uint32_t func_noinline(uint32_t i)
> > {
> > return func_declared_inlined(i + 3);
> > }
> >
> > static uint32_t func_inlined(uint32_t i)
> > {
> > return func_noinline(i + 2);
> > }
> >
> > int main(int argc, char **argv)
> > {
> > uint64_t ret = 0;
> > uint32_t i = 0;
> >
> > for (i = 0; i < 10000000; i++) {
> > ret += func_inlined(i);
> > ret -= func_noinline(i);
> > ret -= func_noinline2(i);
> > ret += func_declared_inlined(i);
> > }
> >
> > printf("%s: %ld\n", __func__, ret);
> > return ret;
> > }
> > ======
> >
> > When built with "gcc -Wall -fno-omit-frame-pointer -O2 -g" (gcc
> > version 12.2.1 20221121 (Red Hat 12.2.1-4) (GCC)) it results in
> > func_inlined() and func_declared_inlined() being inlined into main()
> > and func_declared_inlined() also being inlined into func_noinline().
> >
> > Here are the diffs for 'perf report --call-graph --stdio' output before
> > and after the patch:
> >
> > Frame-pointer mode recorded with 'perf record --call-graph=fp --freq=max -- ./a.out'
> > ======
> > --- unpatched.fp 2023-03-16 13:27:22.724017900 +0100
> > +++ patched.fp 2023-03-16 13:27:28.608857921 +0100
> > @@ -14,18 +14,24 @@
> > ---__libc_start_call_main
> > |
> > |--46.31%--main
> > + | |
> > + | --11.16%--func_declared_inlined (inlined)
> > |
> > |--27.41%--func_noinline
> > + | func_declared_inlined (inlined)
> > |
> > --25.68%--func_noinline2
> >
> > 85.71% 39.64% a.out a.out [.] main
> > |
> > |--46.07%--main
> > + | |
> > + | --11.16%--func_declared_inlined (inlined)
> > |
> > --39.64%--__libc_start_call_main
> > |
> > |--27.17%--func_noinline
> > + | func_declared_inlined (inlined)
> > |
> > --12.23%--func_noinline2
> >
> > @@ -34,31 +40,47 @@
> > |--46.31%--__libc_start_call_main
> > | |
> > | --46.07%--main
> > + | |
> > + | --11.16%--func_declared_inlined (inlined)
> > |
> > --25.44%--func_noinline2
> >
> > 40.56% 13.39% a.out a.out [.] func_noinline
> > |
> > |--27.17%--func_noinline
> > + | func_declared_inlined (inlined)
> > |
> > --13.39%--__libc_start_call_main
> > |
> > --13.15%--func_noinline2
> >
> > + 27.41% 0.00% a.out a.out [.] func_declared_inlined (inlined)
> > + |
> > + ---func_declared_inlined (inlined)
> > +
> > + 11.16% 0.00% a.out a.out [.] func_declared_inlined (inlined)
> > + |
> > + ---func_declared_inlined (inlined)
> > +
> > 0.30% 0.30% a.out [unknown] [k] 0xffffffff81e011b7
> > 0.27% 0.00% a.out ld-linux-x86-64.so.2 [.] _dl_start_user
> > 0.25% 0.00% a.out ld-linux-x86-64.so.2 [.] _dl_sysdep_start
> > 0.20% 0.00% a.out ld-linux-x86-64.so.2 [.] dl_main
> > 0.19% 0.19% a.out [unknown] [k] 0xffffffff81e00193
> > + 0.18% 0.00% a.out a.out [.] func_inlined (inlined)
> > 0.10% 0.05% a.out ld-linux-x86-64.so.2 [.] _dl_relocate_object
> > 0.09% 0.00% a.out [unknown] [k] 0x00007fef811be880
> > 0.09% 0.00% a.out ld-linux-x86-64.so.2 [.] _dl_map_object
> > 0.06% 0.00% a.out libc.so.6 [.] sysmalloc
> > 0.05% 0.00% a.out ld-linux-x86-64.so.2 [.] munmap
> > - 0.05% 0.00% a.out ld-linux-x86-64.so.2 [.] mprotect
> > + 0.05% 0.00% a.out ld-linux-x86-64.so.2 [.] rtld_timer_accum (inlined)
> > + 0.05% 0.00% a.out ld-linux-x86-64.so.2 [.] rtld_timer_stop (inlined)
> > + 0.05% 0.00% a.out ld-linux-x86-64.so.2 [.] __mprotect (inlined)
> > 0.05% 0.00% a.out libc.so.6 [.] __x86_cacheinfo_ifunc
> > + 0.05% 0.00% a.out ld-linux-x86-64.so.2 [.] elf_dynamic_do_Rela (inlined)
> > 0.05% 0.00% a.out ld-linux-x86-64.so.2 [.] _dl_map_object_from_fd
> > - 0.04% 0.00% a.out ld-linux-x86-64.so.2 [.] mmap64
> > + 0.05% 0.00% a.out ld-linux-x86-64.so.2 [.] elf_get_dynamic_info (inlined)
> > + 0.04% 0.00% a.out ld-linux-x86-64.so.2 [.] __mmap64 (inlined)
> > 0.04% 0.04% a.out ld-linux-x86-64.so.2 [.] _dl_cache_libcmp
> > 0.04% 0.00% a.out [unknown] [.] 0x000000000001b19a
> > 0.04% 0.00% a.out [unknown] [k] 0000000000000000
> > @@ -66,13 +88,15 @@
> > 0.04% 0.04% a.out ld-linux-x86-64.so.2 [.] do_lookup_x
> > 0.03% 0.03% a.out ld-linux-x86-64.so.2 [.] intel_check_word.constprop.0
> > 0.03% 0.00% a.out [unknown] [.] 0x0000000004000000
> > + 0.03% 0.00% a.out ld-linux-x86-64.so.2 [.] intel_check_word (inlined)
> > 0.02% 0.00% a.out ld-linux-x86-64.so.2 [.] _dl_start
> > 0.02% 0.02% a.out ld-linux-x86-64.so.2 [.] __GI___tunables_init
> > 0.02% 0.00% a.out [unknown] [.] 0x722f3d4b434f535f
> > 0.02% 0.00% a.out [unknown] [.] 0x00007ffebdd69f59
> > + 0.02% 0.00% a.out ld-linux-x86-64.so.2 [.] tunable_is_name (inlined)
> > 0.01% 0.00% a.out ld-linux-x86-64.so.2 [.] _start
> > ======
> >
> > LBR mode recorded with 'perf record --call-graph=lbr -- ./a.out'
> > ======
> > --- unpatched.lbr 2023-03-16 13:27:50.853253211 +0100
> > +++ patched.lbr 2023-03-16 13:27:56.312104813 +0100
> > @@ -6,58 +6,95 @@
> > # Samples: 238 of event 'cycles:u'
> > # Event count (approx.): 193485873
> > #
> > -# Children Self Command Shared Object Symbol
> > -# ........ ........ ....... .................... .................................
> > +# Children Self Command Shared Object Symbol
> > +# ........ ........ ....... .................... .............................
> > #
> > 99.11% 36.87% a.out a.out [.] main
> > |
> > |--62.24%--main
> > | |
> > - | --17.47%--func_noinline
> > + | |--11.05%--func_inlined (inlined)
> > + | | func_noinline
> > + | | func_declared_inlined (inlined)
> > + | |
> > + | --6.42%--func_noinline
> > + | func_declared_inlined (inlined)
> > |
> > --36.87%--_start
> > - __libc_start_main@@GLIBC_2.34
> > + __libc_start_main_alias_2 (inlined)
> > __libc_start_call_main
> > main
> > |
> > - |--24.52%--func_noinline
> > + |--17.51%--func_inlined (inlined)
> > + | func_noinline
> > + | func_declared_inlined (inlined)
> > + |
> > + |--8.45%--func_noinline2
> > |
> > - --10.01%--func_noinline2
> > + |--7.01%--func_noinline
> > + | func_declared_inlined (inlined)
> > + |
> > + --1.57%--func_declared_inlined (inlined)
> > + func_noinline2
> >
> > 99.11% 0.00% a.out a.out [.] _start
> > |
> > ---_start
> > - __libc_start_main@@GLIBC_2.34
> > + __libc_start_main_alias_2 (inlined)
> > __libc_start_call_main
> > main
> > |
> > - |--41.99%--func_noinline
> > + |--28.55%--func_inlined (inlined)
> > + | func_noinline
> > + | func_declared_inlined (inlined)
> > + |
> > + |--13.43%--func_noinline
> > + | func_declared_inlined (inlined)
> > |
> > - --10.37%--func_noinline2
> > + |--8.81%--func_noinline2
> > + |
> > + --1.57%--func_declared_inlined (inlined)
> > + func_noinline2
> >
> > - 99.11% 0.00% a.out libc.so.6 [.] __libc_start_main@@GLIBC_2.34
> > + 99.11% 0.00% a.out libc.so.6 [.] __libc_start_main_alias_2 (inlined)
> > |
> > - ---__libc_start_main@@GLIBC_2.34
> > + ---__libc_start_main_alias_2 (inlined)
> > __libc_start_call_main
> > main
> > |
> > - |--41.99%--func_noinline
> > + |--28.55%--func_inlined (inlined)
> > + | func_noinline
> > + | func_declared_inlined (inlined)
> > + |
> > + |--13.43%--func_noinline
> > + | func_declared_inlined (inlined)
> > + |
> > + |--8.81%--func_noinline2
> > |
> > - --10.37%--func_noinline2
> > + --1.57%--func_declared_inlined (inlined)
> > + func_noinline2
> >
> > 99.11% 0.00% a.out libc.so.6 [.] __libc_start_call_main
> > |
> > ---__libc_start_call_main
> > main
> > |
> > - |--41.99%--func_noinline
> > + |--28.55%--func_inlined (inlined)
> > + | func_noinline
> > + | func_declared_inlined (inlined)
> > |
> > - --10.37%--func_noinline2
> > + |--13.43%--func_noinline
> > + | func_declared_inlined (inlined)
> > + |
> > + |--8.81%--func_noinline2
> > + |
> > + --1.57%--func_declared_inlined (inlined)
> > + func_noinline2
> >
> > 54.44% 44.43% a.out a.out [.] func_noinline2
> > |
> > |--44.43%--_start
> > - | __libc_start_main@@GLIBC_2.34
> > + | __libc_start_main_alias_2 (inlined)
> > | __libc_start_call_main
> > | main
> > |
> > @@ -66,19 +103,42 @@
> > 41.99% 17.47% a.out a.out [.] func_noinline
> > |
> > |--24.52%--func_noinline
> > + | func_declared_inlined (inlined)
> > |
> > --17.47%--_start
> > - __libc_start_main@@GLIBC_2.34
> > + __libc_start_main_alias_2 (inlined)
> > __libc_start_call_main
> > main
> > - func_noinline
> > + |
> > + |--11.05%--func_inlined (inlined)
> > + | func_noinline
> > + | func_declared_inlined (inlined)
> > + |
> > + --6.42%--func_noinline
> > + func_declared_inlined (inlined)
> > +
> > + 41.99% 0.00% a.out a.out [.] func_declared_inlined (inlined)
> > + |
> > + ---func_declared_inlined (inlined)
> > +
> > + 28.55% 0.00% a.out a.out [.] func_inlined (inlined)
> > + |
> > + ---func_inlined (inlined)
> > + func_noinline
> > + func_declared_inlined (inlined)
> > +
> > + 1.57% 0.00% a.out a.out [.] func_declared_inlined (inlined)
> > + |
> > + ---func_declared_inlined (inlined)
> > + func_noinline2
> >
> > 0.88% 0.00% a.out ld-linux-x86-64.so.2 [.] _start
> > |
> > ---_start
> > _dl_start
> > |
> > - --0.71%--_dl_sysdep_start
> > + --0.71%--_dl_start_final (inlined)
> > + _dl_sysdep_start
> > dl_main
> > _dl_map_object_deps
> > _dl_catch_exception
> > @@ -92,7 +152,8 @@
> > |
> > ---_dl_start
> > |
> > - --0.71%--_dl_sysdep_start
> > + --0.71%--_dl_start_final (inlined)
> > + _dl_sysdep_start
> > dl_main
> > _dl_map_object_deps
> > _dl_catch_exception
> > @@ -106,6 +167,20 @@
> > |
> > ---_start
> > _dl_start
> > + _dl_start_final (inlined)
> > + _dl_sysdep_start
> > + dl_main
> > + _dl_map_object_deps
> > + _dl_catch_exception
> > + openaux
> > + _dl_map_object
> > + _dl_map_object_from_fd
> > + _dl_new_object
> > + strlen
> > +
> > + 0.71% 0.00% a.out ld-linux-x86-64.so.2 [.] _dl_start_final (inlined)
> > + |
> > + ---_dl_start_final (inlined)
> > _dl_sysdep_start
> > dl_main
> > _dl_map_object_deps
> > ======
> >
> > No meaningful differences in output with callchains in dwarf mode or when
> > tracing a binary that was compiled with no dwarf debuginfo.
> >
> > Artem Savkov (1):
> > perf report: append inlines to non-dwarf callchains
> >
> > tools/perf/util/machine.c | 82 ++++++++++++++++++++-------------------
> > 1 file changed, 43 insertions(+), 39 deletions(-)
> >
> > --
> > 2.39.2
> >
>
--
Artem
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