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author | Wang Nan <wangnan0@huawei.com> | 2016-02-05 14:01:27 +0000 |
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committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-02-12 10:54:47 -0300 |
commit | e7ee404757609067c8f261d90251f1e96459c535 (patch) | |
tree | 257a6d1755448ed932f7fff60924d7ae9e17ae8e /tools/perf/util/build-id.h | |
parent | c7ac24178c50a01f14eebcddf5c7b7a2e54676cc (diff) | |
download | linux-e7ee404757609067c8f261d90251f1e96459c535.tar.bz2 |
perf symbols: Fix symbols searching for module in buildid-cache
Before this patch, if a sample is triggered inside a module not in
/lib/modules/`uname -r`/, even if the module is in buildid-cache, 'perf
report' will still be unable to find the correct symbol. For example:
# rm -rf ~/.debug/
# perf buildid-cache -a ./mymodule.ko
# perf probe -m ./mymodule.ko -a get_mymodule_val
Added new event:
probe:get_mymodule_val (on get_mymodule_val in mymodule)
You can now use it in all perf tools, such as:
perf record -e probe:get_mymodule_val -aR sleep 1
# perf record -e probe:get_mymodule_val cat /proc/mymodule
mymodule:3
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.011 MB perf.data (1 samples) ]
# perf report --stdio
[SNIP]
#
# Overhead Command Shared Object Symbol
# ........ ....... ................ ......................
#
100.00% cat [mymodule] [k] 0x0000000000000001
# perf report -vvvv --stdio
dso__load_sym: adjusting symbol: st_value: 0 sh_addr: 0 sh_offset: 0x70
symbol__new: get_mymodule_val 0x70-0x8a
[SNIP]
This is caused by dso__load() -> dso__load_sym(). In dso__load(), kmod
is true only when its file is found in some well know directories. All
files loaded from buildid-cache are treated as user programs. Following
dso__load_sym() set map->pgoff incorrectly.
This patch gives kernel modules in buildid-cache a chance to adjust
value of kmod. After dso__load() get the type of symbols, if it is
buildid, check the last 3 chars of original filename against '.ko', and
adjust the value of kmod if the file is a kernel module.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Cody P Schafer <dev@codyps.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jeremie Galarneau <jeremie.galarneau@efficios.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kirill Smelkov <kirr@nexedi.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1454680939-24963-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/build-id.h')
-rw-r--r-- | tools/perf/util/build-id.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h index 27a14a8a945b..64af3e20610d 100644 --- a/tools/perf/util/build-id.h +++ b/tools/perf/util/build-id.h @@ -16,6 +16,7 @@ int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id); int filename__sprintf_build_id(const char *pathname, char *sbuild_id); char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size); +bool dso__build_id_is_kmod(const struct dso *dso, char *bf, size_t size); int build_id__mark_dso_hit(struct perf_tool *tool, union perf_event *event, struct perf_sample *sample, struct perf_evsel *evsel, |