Hi Jiri,
On 2015/11/17 23:05, Jiri Olsa wrote:
hi,
as reported by Milian, currently for DWARF unwind (both libdw
and libunwind) we display callchain in callee order only.
Adding the support to follow callchain order setup to libunwind
DWARF unwinder, so we could get following output for report:
$ perf record --call-graph dwarf ls
...
$ perf report --no-children --stdio
39.26% ls libc-2.21.so [.] __strcoll_l
|
---__strcoll_l
mpsort_with_tmp
mpsort_with_tmp
sort_files
main
__libc_start_main
_start
0
$ perf report -g caller --no-children --stdio
...
39.26% ls libc-2.21.so [.] __strcoll_l
|
---0
_start
__libc_start_main
main
sort_files
mpsort_with_tmp
mpsort_with_tmp
__strcoll_l
Tested on x86_64. The change is in generic code only,
so it should not affect other archs. Still it would be
nice to have some confirmation.. Wang Nan? ;-)
It'd be nice to have this for libdw unwind as well,
but it looks like it's out of reach for perf code.. Jan?
Also available in:
git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
perf/callchain_1
Thanks for notifying me about this. I have tested it in my environment.
It works well for me except a small behavior changing. Please see below.
Before applying these patch set:
# perf report --no-children --stdio --call-graph=callee
# Overhead Command Shared Object Symbol
# ........ ....... ................ .........................
#
96.61% a.out [vdso] [.] __vdso_gettimeofday
|
---__vdso_gettimeofday
funcc
funcb
funca
main
__libc_start_main
_start
3.38% a.out a.out [.] funcc
|
---funcc
|
--2.70%-- funcb
funca
main
__libc_start_main
_start
0.02% pref_re [kernel.vmlinux] [k] sched_clock
|
---sched_clock
perf_event_nmi_handler
nmi_handle
...
And caller:
# ./perf report --no-children --stdio --call-graph=caller
# Overhead Command Shared Object Symbol
# ........ ....... ................ .........................
#
96.61% a.out [vdso] [.] __vdso_gettimeofday
|
---__vdso_gettimeofday
funcc
funcb
funca
main
__libc_start_main
_start
3.38% a.out a.out [.] funcc
|
---funcc
|
--2.70%-- funcb
funca
main
__libc_start_main
_start
0.02% pref_re [kernel.vmlinux] [k] sched_clock
|
---return_from_execve
sys_execve
do_execveat_common.isra.27
The user code part of output are identical so I confirm the bug.
After applying this patchset:
# ./perf report --no-children --stdio --call-graph=callee
# Overhead Command Shared Object Symbol
# ........ ....... ................ .........................
#
96.61% a.out [vdso] [.] __vdso_gettimeofday
|
---__vdso_gettimeofday
funcc
funcb
funca
main
__libc_start_main
_start
3.38% a.out a.out [.] funcc
|
---funcc
|
|--2.70%-- funcb
| funca
| main
| __libc_start_main
| _start
|
--0.68%-- 0
0.02% pref_re [kernel.vmlinux] [k] sched_clock
|
---sched_clock
perf_event_nmi_handler
...
And caller:
# ./perf report --no-children --stdio --call-graph=caller
# Overhead Command Shared Object Symbol
# ........ ....... ................ .........................
#
96.61% a.out [vdso] [.] __vdso_gettimeofday
|
---_start
__libc_start_main
main
funca
funcb
funcc
__vdso_gettimeofday
3.38% a.out a.out [.] funcc
|
|--2.70%-- _start
| __libc_start_main
| main
| funca
| funcb
| funcc
|
--0.68%-- 0
funcc
0.02% pref_re [kernel.vmlinux] [k] sched_clock
|
---return_from_execve
sys_execve
...
It fixes the bug. However, do you see the extra "0.68%-- 0" in the tree?
I give a message on patch 2/3, please have a look. I think this change
would be okay for me if we treat the old behavior as a bug (for example:
sum of all branches not equal to the overhead of itself). However, the
original code explicitly avoid generating '0' entry so I think we
should make it clear.
Thank you.
thanks,
jirka
Cc: Jan Kratochvil <jkrat...@redhat.com>
---
Jiri Olsa (3):
perf tools: Move initial entry call into get_entries function
perf tools: Add callchain order support for libunwind DWARF unwinder
perf test: Add callchain order setup for DWARF unwinder test
tools/perf/tests/dwarf-unwind.c | 22 +++++++++++++++++++---
tools/perf/util/unwind-libunwind.c | 60
+++++++++++++++++++++++++++++++++++++++---------------------
2 files changed, 58 insertions(+), 24 deletions(-)
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