Commit 9826b273 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
Browse files

ring-buffer: Move the adding of the extended timestamp out of line 



Requiring a extended time stamp is an uncommon occurrence, and it is
best to do it out of line when needed.

Add a noinline function that handles the extended timestamp and
have it called with an unlikely to completely move it out of the
fast path.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent fcc742ea

kernel/trace/ring_buffer.c

+25 −16
Original line number Diff line number Diff line
@@ -2396,6 +2396,29 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer, 
	return NULL;

}



#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK

static inline bool sched_clock_stable(void)

{

	return true;

}

#endif



static noinline void

rb_handle_timestamp(struct ring_buffer_per_cpu *cpu_buffer,

		    struct rb_event_info *info)

{

	WARN_ONCE(info->delta > (1ULL << 59),

		  KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n%s",

		  (unsigned long long)info->delta,

		  (unsigned long long)info->ts,

		  (unsigned long long)cpu_buffer->write_stamp,

		  sched_clock_stable() ? "" :

		  "If you just came from a suspend/resume,\n"

		  "please switch to the trace global clock:\n"

		  "  echo global > /sys/kernel/debug/tracing/trace_clock\n");

	info->add_timestamp = 1;

}



static struct ring_buffer_event *

__rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,

		  struct rb_event_info *info)
@@ -2582,22 +2605,8 @@ rb_reserve_next_event(struct ring_buffer *buffer, 
	/* Did the write stamp get updated already? */

	if (likely(info.ts >= cpu_buffer->write_stamp)) {

		info.delta = diff;

		if (unlikely(test_time_stamp(info.delta))) {

			int local_clock_stable = 1;

#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK

			local_clock_stable = sched_clock_stable();

#endif

			WARN_ONCE(info.delta > (1ULL << 59),

				  KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n%s",

				  (unsigned long long)info.delta,

				  (unsigned long long)info.ts,

				  (unsigned long long)cpu_buffer->write_stamp,

				  local_clock_stable ? "" :

				  "If you just came from a suspend/resume,\n"

				  "please switch to the trace global clock:\n"

				  "  echo global > /sys/kernel/debug/tracing/trace_clock\n");

			info.add_timestamp = 1;

		}

		if (unlikely(test_time_stamp(info.delta)))

			rb_handle_timestamp(cpu_buffer, &info);

	}



	event = __rb_reserve_next(cpu_buffer, &info);

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