perf callchain: Create an address space per thread
The unw_addr_space_t in libunwind represents an address space to be used
for stack unwinding. It doesn't need to be create/destory everytime to
unwind callchain (as in get_entries) and can have a same lifetime as
thread (unless exec called).
So move the address space construction/destruction logic to the thread
lifetime handling functions. This is a preparation to enable caching in
the unwind library.
Note that it saves unw_addr_space_t object using thread__set_priv(). It
seems currently only used by perf trace and perf kvm stat commands which
don't use callchain.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jean Pihet <jean.pihet@linaro.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Arun Sharma <asharma@fb.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1412556363-26229-3-git-send-email-namhyung@kernel.org
[ Fixup unwind-libunwind.c missing CALLCHAIN_DWARF definition, added
missing __maybe_unused on unused parameters in stubs at util/unwind.h ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index a9df7f2..2b7b2d9 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -7,6 +7,7 @@
#include "util.h"
#include "debug.h"
#include "comm.h"
+#include "unwind.h"
int thread__init_map_groups(struct thread *thread, struct machine *machine)
{
@@ -37,6 +38,9 @@
thread->cpu = -1;
INIT_LIST_HEAD(&thread->comm_list);
+ if (unwind__prepare_access(thread) < 0)
+ goto err_thread;
+
comm_str = malloc(32);
if (!comm_str)
goto err_thread;
@@ -48,6 +52,7 @@
goto err_thread;
list_add(&comm->list, &thread->comm_list);
+
}
return thread;
@@ -69,6 +74,7 @@
list_del(&comm->list);
comm__free(comm);
}
+ unwind__finish_access(thread);
free(thread);
}
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index 92b56db..e060386 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -24,6 +24,7 @@
#include <linux/list.h>
#include <libunwind.h>
#include <libunwind-ptrace.h>
+#include "callchain.h"
#include "thread.h"
#include "session.h"
#include "perf_regs.h"
@@ -525,6 +526,35 @@
.get_proc_name = get_proc_name,
};
+int unwind__prepare_access(struct thread *thread)
+{
+ unw_addr_space_t addr_space;
+
+ if (callchain_param.record_mode != CALLCHAIN_DWARF)
+ return 0;
+
+ addr_space = unw_create_addr_space(&accessors, 0);
+ if (!addr_space) {
+ pr_err("unwind: Can't create unwind address space.\n");
+ return -ENOMEM;
+ }
+
+ thread__set_priv(thread, addr_space);
+
+ return 0;
+}
+
+void unwind__finish_access(struct thread *thread)
+{
+ unw_addr_space_t addr_space;
+
+ if (callchain_param.record_mode != CALLCHAIN_DWARF)
+ return;
+
+ addr_space = thread__priv(thread);
+ unw_destroy_addr_space(addr_space);
+}
+
static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
void *arg, int max_stack)
{
@@ -532,11 +562,9 @@
unw_cursor_t c;
int ret;
- addr_space = unw_create_addr_space(&accessors, 0);
- if (!addr_space) {
- pr_err("unwind: Can't create unwind address space.\n");
- return -ENOMEM;
- }
+ addr_space = thread__priv(ui->thread);
+ if (addr_space == NULL)
+ return -1;
ret = unw_init_remote(&c, addr_space, ui);
if (ret)
@@ -549,7 +577,6 @@
ret = ip ? entry(ip, ui->thread, ui->machine, cb, arg) : 0;
}
- unw_destroy_addr_space(addr_space);
return ret;
}
diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
index f030612..c17c485 100644
--- a/tools/perf/util/unwind.h
+++ b/tools/perf/util/unwind.h
@@ -4,6 +4,7 @@
#include <linux/types.h>
#include "event.h"
#include "symbol.h"
+#include "thread.h"
struct unwind_entry {
struct map *map;
@@ -21,6 +22,15 @@
/* libunwind specific */
#ifdef HAVE_LIBUNWIND_SUPPORT
int libunwind__arch_reg_id(int regnum);
+int unwind__prepare_access(struct thread *thread);
+void unwind__finish_access(struct thread *thread);
+#else
+static inline int unwind__prepare_access(struct thread *thread __maybe_unused)
+{
+ return 0;
+}
+
+static inline void unwind__finish_access(struct thread *thread __maybe_unused) {}
#endif
#else
static inline int
@@ -33,5 +43,12 @@
{
return 0;
}
+
+static inline int unwind__prepare_access(struct thread *thread __maybe_unused)
+{
+ return 0;
+}
+
+static inline void unwind__finish_access(struct thread *thread __maybe_unused) {}
#endif /* HAVE_DWARF_UNWIND_SUPPORT */
#endif /* __UNWIND_H */