tracing/branch-tracer: adapt to the stat tracing API
Impact: refactor the branch tracer
This patch adapts the branch tracer to the tracing API.
This is a proof of concept because the branch tracer implements two
"stat tracing" that were split in two files.
So I added an option to the branch tracer: stat_all_branch.
If it is set, then trace_stat will output all of the branches
entries stats. Otherwise, it will print the annotated branches.
Its is a kind of quick trick, waiting for a better solution.
By default, the annotated branches stat are sorted by incorrect branch
prediction percentage.
Ie:
correct incorrect % Function File Line
------- --------- - -------- ---- ----
0 1 100 native_smp_prepare_cpus smpboot.c 1228
0 1 100 hpet_rtc_timer_reinit hpet.c 1057
0 18032 100 sched_info_queued sched_stats.h 223
0 684 100 yield_task_fair sched_fair.c 984
0 282 100 pre_schedule_rt sched_rt.c 1263
0 13414 100 sched_info_dequeued sched_stats.h 178
0 21724 100 sched_info_switch sched_stats.h 270
0 1 100 get_signal_to_deliver signal.c 1820
0 8 100 __cancel_work_timer workqueue.c 560
0 212 100 verify_export_symbols module.c 1509
0 17 100 __rmqueue_fallback page_alloc.c 793
0 43 100 clear_page_mlock internal.h 129
0 124 100 try_to_unmap_anon rmap.c 1021
0 53 100 try_to_unmap_anon rmap.c 1013
0 6 100 vma_address rmap.c 232
0 3301 100 try_to_unmap_file rmap.c 1082
0 466 100 try_to_unmap_file rmap.c 1077
0 1 100 mem_cgroup_create memcontrol.c 1090
0 3 100 inotify_find_update_watch inotify.c 726
2 30163 99 perf_counter_task_sched_out perf_counter.c 385
1 2935 99 percpu_free allocpercpu.c 138
1544 297672 99 dentry_lru_del_init dcache.c 153
8 1074 99 input_pass_event input.c 86
1390 76781 98 mapping_unevictable pagemap.h 50
280 6665 95 pick_next_task_rt sched_rt.c 889
750 4826 86 next_pidmap pid.c 194
2 8 80 blocking_notifier_chain_regist notifier.c 220
36 130 78 ioremap_pte_range ioremap.c 22
1093 3247 74 IS_ERR err.h 34
1023 2908 73 sched_slice sched_fair.c 445
22 60 73 disk_put_part genhd.h 206
[...]
It enables a developer to quickly address the source of incorrect branch
predictions. Note that this sorting would be better with a second sort on
the number of incorrect predictions.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Frederic Weisbecker
Ingo Molnar
parent
dbd0b4b330
commit
e302cf3f96
|
|
@ -18,10 +18,13 @@
|
|||
#include "trace.h"
|
||||
#include "trace_output.h"
|
||||
|
||||
static struct tracer branch_trace;
|
||||
|
||||
#ifdef CONFIG_BRANCH_TRACER
|
||||
|
||||
static int branch_tracing_enabled __read_mostly;
|
||||
static DEFINE_MUTEX(branch_tracing_mutex);
|
||||
|
||||
static struct trace_array *branch_tracer;
|
||||
|
||||
static void
|
||||
|
|
@ -178,6 +181,7 @@ trace_branch_print(struct trace_seq *s, struct trace_entry *entry, int flags)
|
|||
return 0;
|
||||
}
|
||||
|
||||
|
||||
static struct trace_event trace_branch_event = {
|
||||
.type = TRACE_BRANCH,
|
||||
.trace = trace_branch_print,
|
||||
|
|
@ -187,30 +191,6 @@ static struct trace_event trace_branch_event = {
|
|||
.binary = trace_nop_print,
|
||||
};
|
||||
|
||||
struct tracer branch_trace __read_mostly =
|
||||
{
|
||||
.name = "branch",
|
||||
.init = branch_trace_init,
|
||||
.reset = branch_trace_reset,
|
||||
#ifdef CONFIG_FTRACE_SELFTEST
|
||||
.selftest = trace_selftest_startup_branch,
|
||||
#endif
|
||||
};
|
||||
|
||||
__init static int init_branch_trace(void)
|
||||
{
|
||||
int ret;
|
||||
|
||||
ret = register_ftrace_event(&trace_branch_event);
|
||||
if (!ret) {
|
||||
printk(KERN_WARNING "Warning: could not register branch events\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
return register_tracer(&branch_trace);
|
||||
}
|
||||
|
||||
device_initcall(init_branch_trace);
|
||||
#else
|
||||
static inline
|
||||
void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
|
||||
|
|
@ -236,65 +216,38 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect)
|
|||
}
|
||||
EXPORT_SYMBOL(ftrace_likely_update);
|
||||
|
||||
struct ftrace_pointer {
|
||||
void *start;
|
||||
void *stop;
|
||||
int hit;
|
||||
};
|
||||
extern unsigned long __start_annotated_branch_profile[];
|
||||
extern unsigned long __stop_annotated_branch_profile[];
|
||||
|
||||
static void *
|
||||
t_next(struct seq_file *m, void *v, loff_t *pos)
|
||||
static int annotated_branch_stat_headers(struct seq_file *m)
|
||||
{
|
||||
const struct ftrace_pointer *f = m->private;
|
||||
struct ftrace_branch_data *p = v;
|
||||
|
||||
(*pos)++;
|
||||
|
||||
if (v == (void *)1)
|
||||
return f->start;
|
||||
|
||||
++p;
|
||||
|
||||
if ((void *)p >= (void *)f->stop)
|
||||
return NULL;
|
||||
|
||||
return p;
|
||||
}
|
||||
|
||||
static void *t_start(struct seq_file *m, loff_t *pos)
|
||||
{
|
||||
void *t = (void *)1;
|
||||
loff_t l = 0;
|
||||
|
||||
for (; t && l < *pos; t = t_next(m, t, &l))
|
||||
;
|
||||
|
||||
return t;
|
||||
}
|
||||
|
||||
static void t_stop(struct seq_file *m, void *p)
|
||||
{
|
||||
}
|
||||
|
||||
static int t_show(struct seq_file *m, void *v)
|
||||
{
|
||||
const struct ftrace_pointer *fp = m->private;
|
||||
struct ftrace_branch_data *p = v;
|
||||
const char *f;
|
||||
long percent;
|
||||
|
||||
if (v == (void *)1) {
|
||||
if (fp->hit)
|
||||
seq_printf(m, " miss hit %% ");
|
||||
else
|
||||
seq_printf(m, " correct incorrect %% ");
|
||||
seq_printf(m, " Function "
|
||||
seq_printf(m, " correct incorrect %% ");
|
||||
seq_printf(m, " Function "
|
||||
" File Line\n"
|
||||
" ------- --------- - "
|
||||
" -------- "
|
||||
" ---- ----\n");
|
||||
return 0;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline long get_incorrect_percent(struct ftrace_branch_data *p)
|
||||
{
|
||||
long percent;
|
||||
|
||||
if (p->correct) {
|
||||
percent = p->incorrect * 100;
|
||||
percent /= p->correct + p->incorrect;
|
||||
} else
|
||||
percent = p->incorrect ? 100 : -1;
|
||||
|
||||
return percent;
|
||||
}
|
||||
|
||||
static int branch_stat_show(struct seq_file *m, void *v)
|
||||
{
|
||||
struct ftrace_branch_data *p = v;
|
||||
const char *f;
|
||||
long percent;
|
||||
|
||||
/* Only print the file, not the path */
|
||||
f = p->file + strlen(p->file);
|
||||
|
|
@ -305,11 +258,7 @@ static int t_show(struct seq_file *m, void *v)
|
|||
/*
|
||||
* The miss is overlayed on correct, and hit on incorrect.
|
||||
*/
|
||||
if (p->correct) {
|
||||
percent = p->incorrect * 100;
|
||||
percent /= p->correct + p->incorrect;
|
||||
} else
|
||||
percent = p->incorrect ? 100 : -1;
|
||||
percent = get_incorrect_percent(p);
|
||||
|
||||
seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect);
|
||||
if (percent < 0)
|
||||
|
|
@ -320,76 +269,143 @@ static int t_show(struct seq_file *m, void *v)
|
|||
return 0;
|
||||
}
|
||||
|
||||
static struct seq_operations tracing_likely_seq_ops = {
|
||||
.start = t_start,
|
||||
.next = t_next,
|
||||
.stop = t_stop,
|
||||
.show = t_show,
|
||||
};
|
||||
|
||||
static int tracing_branch_open(struct inode *inode, struct file *file)
|
||||
static void *annotated_branch_stat_start(void)
|
||||
{
|
||||
int ret;
|
||||
|
||||
ret = seq_open(file, &tracing_likely_seq_ops);
|
||||
if (!ret) {
|
||||
struct seq_file *m = file->private_data;
|
||||
m->private = (void *)inode->i_private;
|
||||
}
|
||||
|
||||
return ret;
|
||||
return __start_annotated_branch_profile;
|
||||
}
|
||||
|
||||
static const struct file_operations tracing_branch_fops = {
|
||||
.open = tracing_branch_open,
|
||||
.read = seq_read,
|
||||
.llseek = seq_lseek,
|
||||
};
|
||||
static void *
|
||||
annotated_branch_stat_next(void *v, int idx)
|
||||
{
|
||||
struct ftrace_branch_data *p = v;
|
||||
|
||||
++p;
|
||||
|
||||
if ((void *)p >= (void *)__stop_annotated_branch_profile)
|
||||
return NULL;
|
||||
|
||||
return p;
|
||||
}
|
||||
|
||||
static int annotated_branch_stat_cmp(void *p1, void *p2)
|
||||
{
|
||||
struct ftrace_branch_data *a = p1;
|
||||
struct ftrace_branch_data *b = p2;
|
||||
|
||||
long percent_a, percent_b;
|
||||
|
||||
percent_a = get_incorrect_percent(a);
|
||||
percent_b = get_incorrect_percent(b);
|
||||
|
||||
if (percent_a < percent_b)
|
||||
return -1;
|
||||
if (percent_a > percent_b)
|
||||
return 1;
|
||||
else
|
||||
return 0;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_PROFILE_ALL_BRANCHES
|
||||
enum {
|
||||
TRACE_BRANCH_OPT_ALL = 0x1
|
||||
};
|
||||
|
||||
static struct tracer_opt branch_opts[] = {
|
||||
{ TRACER_OPT(stat_all_branch, TRACE_BRANCH_OPT_ALL) },
|
||||
{ }
|
||||
};
|
||||
|
||||
static struct tracer_flags branch_flags = {
|
||||
.val = 0,
|
||||
.opts = branch_opts
|
||||
};
|
||||
|
||||
extern unsigned long __start_branch_profile[];
|
||||
extern unsigned long __stop_branch_profile[];
|
||||
|
||||
static const struct ftrace_pointer ftrace_branch_pos = {
|
||||
.start = __start_branch_profile,
|
||||
.stop = __stop_branch_profile,
|
||||
.hit = 1,
|
||||
};
|
||||
|
||||
#endif /* CONFIG_PROFILE_ALL_BRANCHES */
|
||||
|
||||
extern unsigned long __start_annotated_branch_profile[];
|
||||
extern unsigned long __stop_annotated_branch_profile[];
|
||||
|
||||
static const struct ftrace_pointer ftrace_annotated_branch_pos = {
|
||||
.start = __start_annotated_branch_profile,
|
||||
.stop = __stop_annotated_branch_profile,
|
||||
};
|
||||
|
||||
static __init int ftrace_branch_init(void)
|
||||
static int all_branch_stat_headers(struct seq_file *m)
|
||||
{
|
||||
struct dentry *d_tracer;
|
||||
struct dentry *entry;
|
||||
|
||||
d_tracer = tracing_init_dentry();
|
||||
|
||||
entry = debugfs_create_file("profile_annotated_branch", 0444, d_tracer,
|
||||
(void *)&ftrace_annotated_branch_pos,
|
||||
&tracing_branch_fops);
|
||||
if (!entry)
|
||||
pr_warning("Could not create debugfs "
|
||||
"'profile_annotatet_branch' entry\n");
|
||||
|
||||
#ifdef CONFIG_PROFILE_ALL_BRANCHES
|
||||
entry = debugfs_create_file("profile_branch", 0444, d_tracer,
|
||||
(void *)&ftrace_branch_pos,
|
||||
&tracing_branch_fops);
|
||||
if (!entry)
|
||||
pr_warning("Could not create debugfs"
|
||||
" 'profile_branch' entry\n");
|
||||
#endif
|
||||
|
||||
seq_printf(m, " miss hit %% ");
|
||||
seq_printf(m, " Function "
|
||||
" File Line\n"
|
||||
" ------- --------- - "
|
||||
" -------- "
|
||||
" ---- ----\n");
|
||||
return 0;
|
||||
}
|
||||
|
||||
device_initcall(ftrace_branch_init);
|
||||
static void *all_branch_stat_start(void)
|
||||
{
|
||||
return __start_branch_profile;
|
||||
}
|
||||
|
||||
static void *
|
||||
all_branch_stat_next(void *v, int idx)
|
||||
{
|
||||
struct ftrace_branch_data *p = v;
|
||||
|
||||
++p;
|
||||
|
||||
if ((void *)p >= (void *)__stop_branch_profile)
|
||||
return NULL;
|
||||
|
||||
return p;
|
||||
}
|
||||
|
||||
static int branch_set_flag(u32 old_flags, u32 bit, int set)
|
||||
{
|
||||
if (bit == TRACE_BRANCH_OPT_ALL) {
|
||||
if (set) {
|
||||
branch_trace.stat_headers = all_branch_stat_headers;
|
||||
branch_trace.stat_start = all_branch_stat_start;
|
||||
branch_trace.stat_next = all_branch_stat_next;
|
||||
branch_trace.stat_cmp = NULL;
|
||||
} else {
|
||||
branch_trace.stat_headers =
|
||||
annotated_branch_stat_headers;
|
||||
branch_trace.stat_start = annotated_branch_stat_start;
|
||||
branch_trace.stat_next = annotated_branch_stat_next;
|
||||
branch_trace.stat_cmp = annotated_branch_stat_cmp;
|
||||
}
|
||||
init_tracer_stat(&branch_trace);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
#endif /* CONFIG_PROFILE_ALL_BRANCHES */
|
||||
|
||||
static struct tracer branch_trace __read_mostly =
|
||||
{
|
||||
.name = "branch",
|
||||
#ifdef CONFIG_BRANCH_TRACER
|
||||
.init = branch_trace_init,
|
||||
.reset = branch_trace_reset,
|
||||
#ifdef CONFIG_FTRACE_SELFTEST
|
||||
.selftest = trace_selftest_startup_branch,
|
||||
#endif /* CONFIG_FTRACE_SELFTEST */
|
||||
#endif /* CONFIG_BRANCH_TRACER */
|
||||
.stat_start = annotated_branch_stat_start,
|
||||
.stat_next = annotated_branch_stat_next,
|
||||
.stat_show = branch_stat_show,
|
||||
.stat_headers = annotated_branch_stat_headers,
|
||||
.stat_cmp = annotated_branch_stat_cmp,
|
||||
#ifdef CONFIG_PROFILE_ALL_BRANCHES
|
||||
.flags = &branch_flags,
|
||||
.set_flag = branch_set_flag,
|
||||
#endif
|
||||
};
|
||||
|
||||
__init static int init_branch_trace(void)
|
||||
{
|
||||
#ifdef CONFIG_BRANCH_TRACER
|
||||
int ret;
|
||||
ret = register_ftrace_event(&trace_branch_event);
|
||||
if (!ret) {
|
||||
printk(KERN_WARNING "Warning: could not register branch events\n");
|
||||
return 1;
|
||||
}
|
||||
#endif
|
||||
|
||||
return register_tracer(&branch_trace);
|
||||
}
|
||||
device_initcall(init_branch_trace);
|
||||
|
|
|
|||
Reference in New Issue