Commit-ID: d64ec10ec8b43a519f132e7c33c1815a4e86949e
Gitweb: http://git.kernel.org/tip/d64ec10ec8b43a519f132e7c33c1815a4e86949e
Author: He Kuang <[email protected]>
AuthorDate: Fri, 3 Jun 2016 03:33:19 +0000
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Tue, 7 Jun 2016 15:09:36 -0300
perf unwind: Check the target platform before assigning unwind methods
Currently, 'perf script' uses host unwind methods to parse perf.data
callchain info without taking the target architecture into account, i.e.
assuming the perf.data file was generated on the same machine where the
analysis is being performed. So we get wrong result without any warnings
when unwinding callchains of x86(32-bit) on x86(64-bit) machine.
This patch adds an extra step that checks the target platform before
assigning unwind methods. In later patches in this series, we can use
this info to assign the right unwind methods for supported platforms.
Committer note:
After fixing it to register the local unwinder for live mode tools
('perf trace', 'perf top'), i.e. tools that don't use a perf.data file,
it works as intended and passes the 'perf test unwind' test:
# perf trace -e nanosleep --call dwarf usleep 1
0.328 ( 0.058 ms): usleep/11115 nanosleep(rqtp: 0x7fff083fa480) = 0
__nanosleep_nocancel+0x7
(/usr/lib64/libc-2.22.so)
usleep+0x34 (/usr/lib64/libc-2.22.so)
main+0x1eb (/usr/bin/usleep)
__libc_start_main+0xf0
(/usr/lib64/libc-2.22.so)
_start+0x29 (/usr/bin/usleep)
# perf test 48
48: Test dwarf unwind : Ok
#
Signed-off-by: He Kuang <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Ekaterina Tumanova <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Sukadev Bhattiprolu <[email protected]>
Cc: Wang Nan <[email protected]>
Link:
http://lkml.kernel.org/r/[email protected]
[ Fixed exit path for 'live' mode tools, where we need to default to local
unwinding ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/util/thread.c | 2 +-
tools/perf/util/unwind-libunwind.c | 25 ++++++++++++++++++++++++-
tools/perf/util/unwind.h | 8 +++++---
3 files changed, 30 insertions(+), 5 deletions(-)
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 0bf55256..f30f956 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -202,7 +202,7 @@ int thread__insert_map(struct thread *thread, struct map
*map)
{
int ret;
- ret = unwind__prepare_access(thread);
+ ret = unwind__prepare_access(thread, map);
if (ret)
return ret;
diff --git a/tools/perf/util/unwind-libunwind.c
b/tools/perf/util/unwind-libunwind.c
index f86f903..0086726 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -1,5 +1,8 @@
#include "unwind.h"
#include "thread.h"
+#include "session.h"
+#include "debug.h"
+#include "arch/common.h"
struct unwind_libunwind_ops __weak *local_unwind_libunwind_ops;
@@ -9,8 +12,28 @@ static void unwind__register_ops(struct thread *thread,
thread->unwind_libunwind_ops = ops;
}
-int unwind__prepare_access(struct thread *thread)
+int unwind__prepare_access(struct thread *thread, struct map *map)
{
+ const char *arch;
+ enum dso_type dso_type;
+
+ if (thread->addr_space) {
+ pr_debug("unwind: thread map already set, dso=%s\n",
+ map->dso->name);
+ return 0;
+ }
+
+ /* env->arch is NULL for live-mode (i.e. perf top) */
+ if (!thread->mg->machine->env || !thread->mg->machine->env->arch)
+ goto out_register;
+
+ dso_type = dso__type(map->dso, thread->mg->machine);
+ if (dso_type == DSO__TYPE_UNKNOWN)
+ return 0;
+
+ arch = normalize_arch(thread->mg->machine->env->arch);
+ pr_debug("unwind: target platform=%s\n", arch);
+out_register:
unwind__register_ops(thread, local_unwind_libunwind_ops);
return thread->unwind_libunwind_ops->prepare_access(thread);
diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
index bbd73d9..bf9f593 100644
--- a/tools/perf/util/unwind.h
+++ b/tools/perf/util/unwind.h
@@ -30,11 +30,12 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
/* libunwind specific */
#ifdef HAVE_LIBUNWIND_SUPPORT
int libunwind__arch_reg_id(int regnum);
-int unwind__prepare_access(struct thread *thread);
+int unwind__prepare_access(struct thread *thread, struct map *map);
void unwind__flush_access(struct thread *thread);
void unwind__finish_access(struct thread *thread);
#else
-static inline int unwind__prepare_access(struct thread *thread __maybe_unused)
+static inline int unwind__prepare_access(struct thread *thread __maybe_unused,
+ struct map *map __maybe_unused)
{
return 0;
}
@@ -53,7 +54,8 @@ unwind__get_entries(unwind_entry_cb_t cb __maybe_unused,
return 0;
}
-static inline int unwind__prepare_access(struct thread *thread __maybe_unused)
+static inline int unwind__prepare_access(struct thread *thread __maybe_unused,
+ struct map *map __maybe_unused)
{
return 0;
}
