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Subject[PATCH 2/2] perf script: Support callindent
Date
From: Andi Kleen <ak@linux.intel.com>

When printing PT instruction traces with perf script
it is rather useful to see some indentation for the call tree. This
patch adds a new callindent field to perf script that prints
spaces for the function call stack depth.

We already have code to track the function call stack for PT,
previously used for the data base export. We can reuse that code
directly with minor modifications.

The resulting output is not quite as nice as ftrace yet, but
a lot better than what was there before.

Note there are some corner cases when the thread stack gets code confused
and prints incorrect indentation. Even with that it is fairly useful.

When displaying kernel code traces it is recommended to run as root, as
otherwise perf doesn't understand the kernel addresses properly, and may not
reset the call stack correctly on kernel boundaries.

Example output:

$ perf record -a -e intel_pt// sleep 1
$ perf script --ns -F callindent,time,comm,pid,sym,addr,event --itrace=cr
...
swapper 0 126327.044742970: return: => ffffffff810aa999 cpu_idle_loop
swapper 0 126327.044742970: branches: => ffffffff81525400 cpuidle_reflect
swapper 0 126327.044742970: return: => ffffffff81525400 cpuidle_reflect
swapper 0 126327.044742970: branches: => ffffffff810aa9ce cpu_idle_loop
swapper 0 126327.044742970: return: => ffffffff810aa9ce cpu_idle_loop
swapper 0 126327.044742970: branches: => ffffffff810cb0b0 rcu_idle_exit
swapper 0 126327.044742970: return: => ffffffff810cb0b0 rcu_idle_exit
swapper 0 126327.044742970: branches: => ffffffff810c99d0 rcu_eqs_exit_common.isra.43
swapper 0 126327.044742970: return: => ffffffff810c99d0 rcu_eqs_exit_common.isra.43
swapper 0 126327.044742970: branches: => ffffffff810cb124 rcu_idle_exit
swapper 0 126327.044742970: return: => ffffffff810cb124 rcu_idle_exit
swapper 0 126327.044742970: branches: => ffffffff810aa719 cpu_idle_loop
swapper 0 126327.044742970: return: => ffffffff810aa719 cpu_idle_loop

Cc: adrian.hunter@intel.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
tools/perf/builtin-script.c | 45 ++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/db-export.c | 4 ++--
tools/perf/util/db-export.h | 2 ++
tools/perf/util/thread-stack.c | 7 +++++++
tools/perf/util/thread-stack.h | 1 +
5 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 0e93282b405e..8e24b7b516c6 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -21,6 +21,8 @@
#include "util/cpumap.h"
#include "util/thread_map.h"
#include "util/stat.h"
+#include "util/thread-stack.h"
+#include "util/db-export.h"
#include <linux/bitmap.h>
#include <linux/stringify.h>
#include "asm/bug.h"
@@ -63,6 +65,7 @@ enum perf_output_field {
PERF_OUTPUT_DATA_SRC = 1U << 17,
PERF_OUTPUT_WEIGHT = 1U << 18,
PERF_OUTPUT_BPF_OUTPUT = 1U << 19,
+ PERF_OUTPUT_CALLINDENT = 1U << 20,
};

struct output_option {
@@ -89,6 +92,7 @@ struct output_option {
{.str = "data_src", .field = PERF_OUTPUT_DATA_SRC},
{.str = "weight", .field = PERF_OUTPUT_WEIGHT},
{.str = "bpf-output", .field = PERF_OUTPUT_BPF_OUTPUT},
+ {.str = "callindent", .field = PERF_OUTPUT_CALLINDENT},
};

/* default set to maintain compatibility with current format */
@@ -261,6 +265,11 @@ static int perf_evsel__check_attr(struct perf_evsel *evsel,
PERF_OUTPUT_WEIGHT))
return -EINVAL;

+ if (PRINT_FIELD(CALLINDENT) && !PRINT_FIELD(ADDR)) {
+ pr_err("Display of callindent requested, but no branch address\n");
+ return -EINVAL;
+ }
+
if (PRINT_FIELD(SYM) && !PRINT_FIELD(IP) && !PRINT_FIELD(ADDR)) {
pr_err("Display of symbols requested but neither sample IP nor "
"sample address\nis selected. Hence, no addresses to convert "
@@ -559,6 +568,39 @@ static void print_sample_addr(struct perf_sample *sample,
}
}

+static int dummy_call_return(struct call_return *cr __maybe_unused,
+ void *arg __maybe_unused)
+{
+ return 0;
+}
+
+static void print_sample_callindent(struct perf_sample *sample,
+ struct perf_evsel *evsel,
+ struct thread *thread,
+ struct addr_location *al)
+{
+ struct perf_event_attr *attr = &evsel->attr;
+
+ if (sample_addr_correlates_sym(attr)) {
+ static struct call_return_processor *crp;
+ struct addr_location addr_al;
+ struct thread *main_thread;
+ struct comm *comm;
+
+ if (!crp)
+ crp = call_return_processor__new(dummy_call_return,
+ NULL);
+ thread__resolve(thread, &addr_al, sample);
+ main_thread = db_export__main_thread(al->machine, thread);
+ if (main_thread)
+ comm = machine__thread_exec_comm(al->machine,
+ main_thread);
+ thread_stack__process(thread, comm, sample, al, &addr_al,
+ 0, crp);
+ }
+ thread_stack__print_indent(thread);
+}
+
static void print_sample_bts(struct perf_sample *sample,
struct perf_evsel *evsel,
struct thread *thread,
@@ -567,6 +609,9 @@ static void print_sample_bts(struct perf_sample *sample,
struct perf_event_attr *attr = &evsel->attr;
bool print_srcline_last = false;

+ if (PRINT_FIELD(CALLINDENT))
+ print_sample_callindent(sample, evsel, thread, al);
+
/* print branch_from information */
if (PRINT_FIELD(IP)) {
unsigned int print_opts = output[attr->type].print_ip_opts;
diff --git a/tools/perf/util/db-export.c b/tools/perf/util/db-export.c
index 049438d51b9a..02f8255a0b01 100644
--- a/tools/perf/util/db-export.c
+++ b/tools/perf/util/db-export.c
@@ -231,7 +231,7 @@ int db_export__symbol(struct db_export *dbe, struct symbol *sym,
return 0;
}

-static struct thread *get_main_thread(struct machine *machine, struct thread *thread)
+struct thread *db_export__main_thread(struct machine *machine, struct thread *thread)
{
if (thread->pid_ == thread->tid)
return thread__get(thread);
@@ -308,7 +308,7 @@ int db_export__sample(struct db_export *dbe, union perf_event *event,
if (err)
return err;

- main_thread = get_main_thread(al->machine, thread);
+ main_thread = db_export__main_thread(al->machine, thread);
if (main_thread)
comm = machine__thread_exec_comm(al->machine, main_thread);

diff --git a/tools/perf/util/db-export.h b/tools/perf/util/db-export.h
index 25e22fd76aca..8cb3658172d9 100644
--- a/tools/perf/util/db-export.h
+++ b/tools/perf/util/db-export.h
@@ -103,4 +103,6 @@ int db_export__branch_types(struct db_export *dbe);
int db_export__call_path(struct db_export *dbe, struct call_path *cp);
int db_export__call_return(struct db_export *dbe, struct call_return *cr);

+struct thread *db_export__main_thread(struct machine *machine, struct thread *thread);
+
#endif
diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c
index 679688e70ae7..abea25eb2ccc 100644
--- a/tools/perf/util/thread-stack.c
+++ b/tools/perf/util/thread-stack.c
@@ -753,3 +753,10 @@ int thread_stack__process(struct thread *thread, struct comm *comm,

return err;
}
+
+void thread_stack__print_indent(struct thread *thread)
+{
+ if (!thread->ts)
+ return;
+ printf("%*s", (int)thread->ts->cnt * 4, "");
+}
diff --git a/tools/perf/util/thread-stack.h b/tools/perf/util/thread-stack.h
index e1528f1374c3..d7426bd0510b 100644
--- a/tools/perf/util/thread-stack.h
+++ b/tools/perf/util/thread-stack.h
@@ -98,6 +98,7 @@ void thread_stack__sample(struct thread *thread, struct ip_callchain *chain,
size_t sz, u64 ip);
int thread_stack__flush(struct thread *thread);
void thread_stack__free(struct thread *thread);
+void thread_stack__print_indent(struct thread *thread);

struct call_return_processor *
call_return_processor__new(int (*process)(struct call_return *cr, void *data),
--
2.5.5
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