Support basic dwarf(debuginfo) based operations for uprobe events. With
this change, perf probe can analyze debuginfo of user application binary
to set up new uprobe event.
This allows perf-probe --add(with local variables, line numbers) and
--line works with -x option. (Actually, --vars has already accepted -x
option)
For example, the following command shows the probe-able lines of a given
user space function. Something that so far was only available in the
'perf probe' tool for kernel space functions:
# ./perf probe -x perf --line map__load
<map__load@/home/fedora/ksrc/linux-2.6/tools/perf/util/map.c:0>
0 int map__load(struct map *map, symbol_filter_t filter)
1 {
2 const char *name = map->dso->long_name;
int nr;
5 if (dso__loaded(map->dso, map->type))
6 return 0;
8 nr = dso__load(map->dso, map, filter);
9 if (nr < 0) {
10 if (map->dso->has_build_id) {
And this shows the available variables at the given line of the
function.
# ./perf probe -x perf --vars map__load:8
Available variables at map__load:8
@<map__load+96>
char* name
struct map* map
symbol_filter_t filter
@<map__find_symbol+112>
char* name
symbol_filter_t filter
@<map__find_symbol_by_name+136>
char* name
symbol_filter_t filter
@<map_groups__find_symbol_by_name+176>
char* name
struct map* map
symbol_filter_t filter
And lastly, we can now define probe(s) with all available
variables on the given line:
# ./perf probe -x perf --add 'map__load:8 $vars'
Added new events:
probe_perf:map__load (on map__load:8 with $vars)
probe_perf:map__load_1 (on map__load:8 with $vars)
probe_perf:map__load_2 (on map__load:8 with $vars)
probe_perf:map__load_3 (on map__load:8 with $vars)
You can now use it in all perf tools, such as:
perf record -e probe_perf:map__load_3 -aR sleep 1
Changes from previous version:
- Add examples in the patch description.
- Use .text section start address and dwarf symbol address
for calculating the offset of given symbol, instead of
searching the symbol in symtab again.
With this change, we can safely handle multiple local
function instances (e.g. scnprintf in perf).
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: David A. Long <dave.long@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: systemtap@sourceware.org
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20131226054152.22364.47021.stgit@kbuild-fedora.novalocal
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently, if we use perf kvm --guestkallsyms --guestmodules report, we
can not get the perf information from perf data file. All sample are
shown as unknown.
Reproducing steps:
# perf kvm --guestkallsyms /tmp/kallsyms --guestmodules /tmp/modules record -a sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.624 MB perf.data.guest (~27260 samples) ]
# perf kvm --guestkallsyms /tmp/kallsyms --guestmodules /tmp/modules report |grep %
100.00% [guest/6471] [unknown] [g] 0xffffffff8164f330
This bug was introduced by 207b57926 (perf kvm: Fix regression with guest machine creation).
In original code, it uses perf_session__find_machine(), it means we deliver symbol to machine
which has the same pid, if no machine found, deliver it to *default* guest. But if we use
perf_session__findnew_machine() here, if no machine was found, new machine with pid will be built
and added. Then the default guest which with pid == 0 will never get a symbol.
And because the new machine initialized here has no kernel map created, the symbol delivered to
it will be marked as "unknown".
This patch here is to revert commit 207b57926 and fix the SEGFAULT bug in another way.
Verification steps:
# ./perf kvm --guestkallsyms /home/kallsyms --guestmodules /home/modules record -a sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.651 MB perf.data.guest (~28437 samples) ]
# ./perf kvm --guestkallsyms /home/kallsyms --guestmodules /home/modules report |grep %
22.64% :6471 [guest.kernel.kallsyms] [g] update_rq_clock.part.70
19.99% :6471 [guest.kernel.kallsyms] [g] d_free
18.46% :6471 [guest.kernel.kallsyms] [g] bio_phys_segments
16.25% :6471 [guest.kernel.kallsyms] [g] dequeue_task
12.78% :6471 [guest.kernel.kallsyms] [g] __switch_to
7.91% :6471 [guest.kernel.kallsyms] [g] scheduler_tick
1.75% :6471 [guest.kernel.kallsyms] [g] native_apic_mem_write
0.21% :6471 [guest.kernel.kallsyms] [g] apic_timer_interrupt
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: stable@vger.kernel.org # 3.3+
Cc: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/1387564907-3045-1-git-send-email-yangds.fnst@cn.fujitsu.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It was called "data_type", but in this context "data" is way too vague,
it could mean the "data" ELF segment, or something else.
Since we have dso__read_binary_type_filename() and the values this field
receives are all DSO__BINARY_TYPE_<FOO> we may as well call it
"binary_type" for consistency sake.
It also seems more appropriate since it determines if we can do
operations like annotation and DWARF unwinding, that needs more than
just the symtab, requiring access to ELF text segments, CFI ELF
sections, etc.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-2lkbqrn23uc2uvnn9w9in379@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Arnaldo Carvalho de Melo
Masami Hiramatsu
Dongsheng Yang
Namhyung Kim
Stanislav Fomichev