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46d21ec067
Append information about inlined functions to FP and LBR callchains from
DWARF debuginfo when available. Do so by calling append_inlines() from
add_callchain_ip().
Testing it:
Frame-pointer mode recorded with 'perf record --call-graph=fp --freq=max -- ./a.out'
#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.
Committer notes:
Adrian Hunter pointed out that this breaks --branch-history, so don't do
it for branches, see the second Link below.
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: <asavkov@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230316133557.868731-2-asavkov@redhat.com
Link: https://lore.kernel.org/r/54129783-2960-84e1-05e9-97ac70ffb432@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.