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ftrace: Show timings of how long nop patching took

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Since the beginning of ftrace, the code that did the patching had its
timings saved on how long it took to complete. But this information was
never exposed. It was used for debugging and exposing it was always
something that was on the TODO list. Now it's time to expose it. There's
even a file that is where it should go!

Also include how long patching modules took as a separate value.

 # cat /sys/kernel/tracing/dyn_ftrace_total_info
 57680 pages:231 groups: 9
 ftrace boot update time = 14024666 (ns)
 ftrace module total update time = 126070 (ns)

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/20241017113105.1edfa943@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2024-10-17 11:31:05 -04:00 committed by Steven Rostedt (Google)
parent 8b0cb3a4c5
commit 36a367b891
3 changed files with 21 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
kernel/trace/ftrace.c
View File

@ -3686,7 +3686,8 @@ static int ftrace_hash_move_and_update_subops(struct ftrace_ops *subops,
}
static u64 ftrace_update_time;
u64 ftrace_update_time;
u64 ftrace_total_mod_time;
unsigned long ftrace_update_tot_cnt;
unsigned long ftrace_number_of_pages;
unsigned long ftrace_number_of_groups;
@ -3706,7 +3707,7 @@ static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
bool init_nop = ftrace_need_init_nop();
struct ftrace_page *pg;
struct dyn_ftrace *p;
u64 start, stop;
u64 start, stop, update_time;
unsigned long update_cnt = 0;
unsigned long rec_flags = 0;
int i;
@ -3750,7 +3751,11 @@ static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
}
stop = ftrace_now(raw_smp_processor_id());
ftrace_update_time = stop - start;
update_time = stop - start;
if (mod)
ftrace_total_mod_time += update_time;
else
ftrace_update_time = update_time;
ftrace_update_tot_cnt += update_cnt;
return 0;

15
kernel/trace/trace.c
View File

@ -8548,15 +8548,22 @@ tracing_read_dyn_info(struct file *filp, char __user *ubuf,
char *buf;
int r;
/* 256 should be plenty to hold the amount needed */
buf = kmalloc(256, GFP_KERNEL);
/* 512 should be plenty to hold the amount needed */
#define DYN_INFO_BUF_SIZE 512
buf = kmalloc(DYN_INFO_BUF_SIZE, GFP_KERNEL);
if (!buf)
return -ENOMEM;
r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n",
r = scnprintf(buf, DYN_INFO_BUF_SIZE,
"%ld pages:%ld groups: %ld\n"
"ftrace boot update time = %llu (ns)\n"
"ftrace module total update time = %llu (ns)\n",
ftrace_update_tot_cnt,
ftrace_number_of_pages,
ftrace_number_of_groups);
ftrace_number_of_groups,
ftrace_update_time,
ftrace_total_mod_time);
ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
kfree(buf);

2
kernel/trace/trace.h
View File

@ -775,6 +775,8 @@ extern void trace_event_follow_fork(struct trace_array *tr, bool enable);
extern unsigned long ftrace_update_tot_cnt;
extern unsigned long ftrace_number_of_pages;
extern unsigned long ftrace_number_of_groups;
extern u64 ftrace_update_time;
extern u64 ftrace_total_mod_time;
void ftrace_init_trace_array(struct trace_array *tr);
#else
static inline void ftrace_init_trace_array(struct trace_array *tr) { }