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Message-ID: <20151119112218.GA12585@krava.local>
Date: Thu, 19 Nov 2015 12:22:34 +0100
From: Jiri Olsa <jolsa@...hat.com>
To: Jiri Olsa <jolsa@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
Jan Kratochvil <jkratoch@...hat.com>,
lkml <linux-kernel@...r.kernel.org>,
David Ahern <dsahern@...il.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Milian Wolff <milian.wolff@...b.com>,
Wang Nan <wangnan0@...wei.com>
Subject: [PATCH 4/3] perf tools: Add callchain order support for libdw DWARF
unwinder
On Tue, Nov 17, 2015 at 04:05:36PM +0100, Jiri Olsa wrote:
SNIP
> Tested on x86_64. The change is in generic code only,
> so it should not affect other archs. Still it would be
> nice to have some confirmation.. Wang Nan? ;-)
>
> It'd be nice to have this for libdw unwind as well,
> but it looks like it's out of reach for perf code.. Jan?
>
> Also available in:
> git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
> perf/callchain_1
adding also libdw support.. test with 'make NO_LIBUNWIND=1'
Also available in:
git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
perf/callchain_3
thanks,
jirka
---
As reported by Milian, currently for DWARF unwind (both libdw
and libunwind) we display callchain in callee order only.
Adding the support to follow callchain order setup to libdw
DWARF unwinder, so we could get following output for report:
$ perf record --call-graph dwarf ls
...
$ perf report --no-children --stdio
13.63% ls [kernel.vmlinux] [k] __rb_insert_augmented
|
---__rb_insert_augmented
__vma_link_rb
vma_link
do_brk
vm_brk
load_elf_binary
search_binary_handler
do_execveat_common.isra.29
sys_execve
return_from_execve
$ perf report --stdio --no-children -g caller
13.63% ls [kernel.vmlinux] [k] __rb_insert_augmented
|
---return_from_execve
sys_execve
do_execveat_common.isra.29
search_binary_handler
load_elf_binary
vm_brk
do_brk
vma_link
__vma_link_rb
__rb_insert_augmented
Reported-by: Milian Wolff <milian.wolff@...b.com>
Link: http://lkml.kernel.org/n/tip-zk99ay9s71whl9qd9if28u8z@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
tools/perf/util/unwind-libdw.c | 53 ++++++++++++++++++++++++++++++------------
tools/perf/util/unwind-libdw.h | 2 ++
2 files changed, 40 insertions(+), 15 deletions(-)
diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
index 2dcfe9a7c8d0..db8142ba7cb9 100644
--- a/tools/perf/util/unwind-libdw.c
+++ b/tools/perf/util/unwind-libdw.c
@@ -11,6 +11,7 @@
#include <linux/types.h>
#include "event.h"
#include "perf_regs.h"
+#include "callchain.h"
static char *debuginfo_path;
@@ -52,25 +53,28 @@ static int report_module(u64 ip, struct unwind_info *ui)
return __report_module(&al, ip, ui);
}
+/*
+ * Store all entries within entries array,
+ * we will process it after we finish unwind.
+ */
static int entry(u64 ip, struct unwind_info *ui)
{
- struct unwind_entry e;
+ struct unwind_entry *e = &ui->entries[ui->idx++];
struct addr_location al;
if (__report_module(&al, ip, ui))
return -1;
- e.ip = ip;
- e.map = al.map;
- e.sym = al.sym;
+ e->ip = ip;
+ e->map = al.map;
+ e->sym = al.sym;
pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
al.sym ? al.sym->name : "''",
ip,
al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
-
- return ui->cb(&e, ui->arg);
+ return 0;
}
static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp)
@@ -168,7 +172,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
struct perf_sample *data,
int max_stack)
{
- struct unwind_info ui = {
+ struct unwind_info *ui, ui_buf = {
.sample = data,
.thread = thread,
.machine = thread->mg->machine,
@@ -177,35 +181,54 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
.max_stack = max_stack,
};
Dwarf_Word ip;
- int err = -EINVAL;
+ int err = -EINVAL, i;
if (!data->user_regs.regs)
return -EINVAL;
- ui.dwfl = dwfl_begin(&offline_callbacks);
- if (!ui.dwfl)
+ ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack);
+ if (!ui)
+ return -ENOMEM;
+
+ *ui = ui_buf;
+
+ ui->dwfl = dwfl_begin(&offline_callbacks);
+ if (!ui->dwfl)
goto out;
err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP);
if (err)
goto out;
- err = report_module(ip, &ui);
+ err = report_module(ip, ui);
if (err)
goto out;
- if (!dwfl_attach_state(ui.dwfl, EM_NONE, thread->tid, &callbacks, &ui))
+ if (!dwfl_attach_state(ui->dwfl, EM_NONE, thread->tid, &callbacks, ui))
goto out;
- err = dwfl_getthread_frames(ui.dwfl, thread->tid, frame_callback, &ui);
+ err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui);
- if (err && !ui.max_stack)
+ if (err && !ui->max_stack)
err = 0;
+ /*
+ * Display what we got based on the order setup.
+ */
+ for (i = 0; i < ui->idx && !err; i++) {
+ int j = i;
+
+ if (callchain_param.order == ORDER_CALLER)
+ j = ui->idx - i - 1;
+
+ err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0;
+ }
+
out:
if (err)
pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));
- dwfl_end(ui.dwfl);
+ dwfl_end(ui->dwfl);
+ free(ui);
return 0;
}
diff --git a/tools/perf/util/unwind-libdw.h b/tools/perf/util/unwind-libdw.h
index 417a1426f3ad..58328669ed16 100644
--- a/tools/perf/util/unwind-libdw.h
+++ b/tools/perf/util/unwind-libdw.h
@@ -16,6 +16,8 @@ struct unwind_info {
unwind_entry_cb_t cb;
void *arg;
int max_stack;
+ int idx;
+ struct unwind_entry entries[];
};
#endif /* __PERF_UNWIND_LIBDW_H */
--
2.4.3
--
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