Commit 66f066d8 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarNamhyung Kim <namhyung@kernel.org>
Acked-by: default avatarJean Pihet <jean.pihet@linaro.org>
Acked-by: default avatarJiri 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 0cdccac6

tools/perf/util/thread.c

+6 −0
Original line number Diff line number Diff line
@@ -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 @@ struct thread *thread__new(pid_t pid, pid_t tid) 
		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 @@ struct thread *thread__new(pid_t pid, pid_t tid) 
			goto err_thread;



		list_add(&comm->list, &thread->comm_list);



	}



	return thread;
@@ -69,6 +74,7 @@ void thread__delete(struct thread *thread) 
		list_del(&comm->list);

		comm__free(comm);

	}

	unwind__finish_access(thread);



	free(thread);

}

tools/perf/util/unwind-libunwind.c

+32 −5
Original line number Diff line number Diff line
@@ -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"
@@ -525,12 +526,12 @@ static unw_accessors_t accessors = { 
	.get_proc_name		= get_proc_name,

};



static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,

		       void *arg, int max_stack)

int unwind__prepare_access(struct thread *thread)

{

	unw_addr_space_t addr_space;

	unw_cursor_t c;

	int ret;



	if (callchain_param.record_mode != CALLCHAIN_DWARF)

		return 0;



	addr_space = unw_create_addr_space(&accessors, 0);

	if (!addr_space) {
@@ -538,6 +539,33 @@ static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb, 
		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)

{

	unw_addr_space_t addr_space;

	unw_cursor_t c;

	int ret;



	addr_space = thread__priv(ui->thread);

	if (addr_space == NULL)

		return -1;



	ret = unw_init_remote(&c, addr_space, ui);

	if (ret)

		display_error(ret);
@@ -549,7 +577,6 @@ static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb, 
		ret = ip ? entry(ip, ui->thread, ui->machine, cb, arg) : 0;

	}



	unw_destroy_addr_space(addr_space);

	return ret;

}

tools/perf/util/unwind.h

+17 −0
Original line number Diff line number Diff line
@@ -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 @@ 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);

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 @@ unwind__get_entries(unwind_entry_cb_t cb __maybe_unused, 
{

	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 */

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