LBR call stack only has user-space callchains. It is output in the
PERF_SAMPLE_BRANCH_STACK data format. For kernel callchains, it's
still in the form of PERF_SAMPLE_CALLCHAIN.
The perf tool has to handle both data sources to construct a
complete callstack.
For the "perf report -D" option, both lbr and fp information will be
displayed.
A new call chain recording option "lbr" is introduced into the perf
tool for LBR call stack. The user can use --call-graph lbr to get
the call stack information from hardware.
Here are some examples.
When profiling bc(1) on Fedora 19:
echo 'scale=2000; 4*a(1)' > cmd; perf record --call-graph lbr bc -l < cmd
If enabling LBR, perf report output looks like:
50.36% bc bc [.] bc_divide
|
--- bc_divide
execute
run_code
yyparse
main
__libc_start_main
_start
33.66% bc bc [.] _one_mult
|
--- _one_mult
bc_divide
execute
run_code
yyparse
main
__libc_start_main
_start
7.62% bc bc [.] _bc_do_add
|
--- _bc_do_add
|
|--99.89%-- 0x2000186a8
--0.11%-- [...]
6.83% bc bc [.] _bc_do_sub
|
--- _bc_do_sub
|
|--99.94%-- bc_add
| execute
| run_code
| yyparse
| main
| __libc_start_main
| _start
--0.06%-- [...]
0.46% bc libc-2.17.so [.] __memset_sse2
|
--- __memset_sse2
|
|--54.13%-- bc_new_num
| |
| |--51.00%-- bc_divide
| | execute
| | run_code
| | yyparse
| | main
| | __libc_start_main
| | _start
| |
| |--30.46%-- _bc_do_sub
| | bc_add
| | execute
| | run_code
| | yyparse
| | main
| | __libc_start_main
| | _start
| |
| --18.55%-- _bc_do_add
| bc_add
| execute
| run_code
| yyparse
| main
| __libc_start_main
| _start
|
--45.87%-- bc_divide
execute
run_code
yyparse
main
__libc_start_main
_start
If using FP, perf report output looks like:
echo 'scale=2000; 4*a(1)' > cmd; perf record --call-graph fp bc -l < cmd
50.49% bc bc [.] bc_divide
|
--- bc_divide
33.57% bc bc [.] _one_mult
|
--- _one_mult
7.61% bc bc [.] _bc_do_add
|
--- _bc_do_add
0x2000186a8
6.88% bc bc [.] _bc_do_sub
|
--- _bc_do_sub
0.42% bc libc-2.17.so [.] __memcpy_ssse3_back
|
--- __memcpy_ssse3_back
If using LBR, perf report -D output looks like:
3458145275743 0x2fd750 [0xd8]: PERF_RECORD_SAMPLE(IP, 0x2): 9748/9748: 0x408ea8 period: 609644 addr: 0
... LBR call chain: nr:8
..... 0: fffffffffffffe00
..... 1: 0000000000408e50
..... 2: 000000000040a458
..... 3: 000000000040562e
..... 4: 0000000000408590
..... 5: 00000000004022c0
..... 6: 00000000004015dd
..... 7: 0000003d1cc21b43
... FP chain: nr:2
..... 0: fffffffffffffe00
..... 1: 0000000000408ea8
... thread: bc:9748
...... dso: /usr/bin/bc
The LBR call stack has the following known limitations:
- Zero length calls are not filtered out by the hardware
- Exception handing such as setjmp/longjmp will have calls/returns not
match
- Pushing different return address onto the stack will have
calls/returns not match
- If callstack is deeper than the LBR, only the last entries are
captured
Tested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Simon Que <sque@chromium.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1420482185-29830-3-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The perf_event_attr.task bit is to track task (fork and exit) events but
it missed to be set by perf_evsel__config(). While it was not a problem
in practice since setting other bits (comm/mmap) ended up being in same
result, it'd be good to set it explicitly anyway.
The attr->task is to track task related events (fork/exit) only but
other meta events like comm and mmap[2] also needs the task events. So
setting attr->comm and/or attr->mmap causes the kernel emits the task
events anyway. So the attr->task is only meaningful when other bits are
off but I'd like to set it for completeness.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1422518843-25818-6-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
After perf record finishes, it prints file size and number of samples in
the file but this info is wrong since it assumes typical sample size of
24 bytes and divides file size by the value.
However as we post-process recorded samples for build-id, it can show
correct number like below. If build-id post-processing is not requested
just omit the wrong number of samples.
$ perf record noploop 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.159 MB perf.data (3989 samples) ]
$ perf report --stdio -n
# To display the perf.data header info, please use --header/--header-only options.
#
# Samples: 3K of event 'cycles'
# Event count (approx.): 3771330663
#
# Overhead Samples Command Shared Object Symbol
# ........ ............ ....... ................ ..........................
#
99.90% 3982 noploop noploop [.] main
0.09% 1 noploop ld-2.17.so [.] _dl_check_map_versions
0.01% 1 noploop [kernel.vmlinux] [k] setup_arg_pages
0.00% 5 noploop [kernel.vmlinux] [k] intel_pmu_enable_all
Reported-by: Milian Wolff <mail@milianw.de>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1422518843-25818-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
uClibc Linuxthreads.old doesn't support the pthread_attr_setaffinity_np()
functioo:
----------------->8-----------------------
CC bench/futex-hash.o
CC bench/futex-wake.o
bench/futex-hash.c: In function 'bench_futex_hash':
bench/futex-hash.c:161:3: error: implicit declaration of function
'pthread_attr_setaffinity_np' [-Werror=implicit-function-declaration]
ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t),
&cpu);
^
bench/futex-hash.c:161:3: error: nested extern declaration of
'pthread_attr_setaffinity_np' [-Werror=nested-externs]
----------------->8-----------------------
So introduce a test to check that and if not available provide a stub.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1421156604-30603-6-git-send-email-vgupta@synopsys.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When running perf on ARC (uClibc based userspace), ran into this issue
------------->8----------------
[ARCLinux]$ ./perf record ls
bin etc perf sys
debug init perf.data tmp
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.001 MB perf.data (~24 samples) ]
[ARCLinux]$ ./perf report
incompatible file format (rerun with -v to learn more)
------------->8----------------
The problem happens in the following call stack when zalloc is called
with size zero
glibc default / uClibc with MALLOC_GLIBC_COMPAT are OK, but not if that
config option is not enabled.
cmd_report
perf_session__new
perf_session__open
perf_session__read_header
read_attr(fd, header, &f_attr)
nr_ids = f_attr.ids.size / sizeof(u64); <-- 0
perf_evsel__alloc_id(vsel, 1, nr_ids)
zalloc(ncpus * nthreads * sizeof(u64)) <-- 0
header.c: read_attr()
(gdb) p *f_attr
$17 = {
attr = {
type = 0,
size = 96,
config = 0,
{
sample_period = 4000,
sample_freq = 4000
},
...
ids = {
offset = 104,
size = 0 <------
}
}
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Suggested-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1421156604-30603-5-git-send-email-vgupta@synopsys.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The new hw_breakpoint bits are now ready for v3.20, merge them
into the main branch, to avoid conflicts.
Conflicts:
tools/perf/Documentation/perf-record.txt
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add helpers for the following kernel formats:
%pi4 print an IPv4 address with leading zeros
%pI4 print an IPv4 address without leading zeros
%pi6 print an IPv6 address without colons
%pI6 print an IPv6 address with colons
%pI6c print an IPv6 address in compressed form with colons
%pISpc print an IP address from a sockaddr
Allows these formats to be used in tracepoints.
Quite a bit of this is adapted from code in lib/vsprintf.c.
v4:
- fixed pI6c description in git commit message per Valdis' comment
v3:
- use of 'c' and 'p' requires 'I'
v2:
- pass ptr+1 to print_ip_arg per Namhyung's comments
- added field length checks to sockaddr function
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1418955071-36241-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When perf exits with some error it shows the error message with
ui__error() or ui__warning() and then calls ui__exit() during
exit_browser().
On TUI, it then shows a window titled "Fatal Error" to inform user a
last message which might be related with this condition. However it
sometimes contains no message and just annoyes users.
The usual case for this is running perf top as normal user. (And
/proc/sys/kernel/perf_event_paranoid being 1).
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1421736050-5283-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The prior change fixes default output ordering with each column but it
breaks -o/--order option. This patch prepends a new hpp fmt struct to
sort list but not to output field list so that it can affect ordering
without adding a new output column.
The new hpp fmt uses its own compare functions which treats dummy
entries (which have no baseline) little differently - the delta field
can be computed without baseline but others (ratio and wdiff) are not.
The new output will look like below:
$ perf diff -o 2 perf.data.{old,cur,new}
...
# Baseline/0 Delta/1 Delta/2 Shared Object Symbol
# .......... ....... ....... ................. ..........................................
22.98% +0.51% +0.52% libc-2.20.so [.] _int_malloc
5.70% +0.28% +0.30% libc-2.20.so [.] free
4.38% -0.21% +0.25% a.out [.] main
1.32% -0.15% +0.05% a.out [.] free@plt
+0.01% [kernel.kallsyms] [k] intel_pstate_timer_func
+0.01% [kernel.kallsyms] [k] _raw_spin_lock_irqsave
+0.01% [kernel.kallsyms] [k] timekeeping_update.constprop.8
+0.01% +0.01% [kernel.kallsyms] [k] apic_timer_interrupt
0.01% -0.00% [kernel.kallsyms] [k] native_read_msr_safe
0.01% -0.01% -0.01% [kernel.kallsyms] [k] native_write_msr_safe
1.31% +0.03% -0.06% a.out [.] malloc@plt
31.50% -0.74% -0.23% libc-2.20.so [.] _int_free
32.75% +0.28% -0.83% libc-2.20.so [.] malloc
0.01% [kernel.kallsyms] [k] scheduler_tick
+0.01% [kernel.kallsyms] [k] read_tsc
+0.01% [kernel.kallsyms] [k] perf_adjust_freq_unthr_context.part.82
In above example, the output was sorted by 'Delta/2' column first, and
then 'Baseline/0' and finally 'Delta/1'.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1420677949-6719-8-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Kan Liang
Namhyung Kim
Vineet Gupta
Ingo Molnar
David Ahern
Rasmus Villemoes
Arnaldo Carvalho de Melo