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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: Steven Rostedt <rostedt@goodmis.org>
hifive-unleashed-5.1
Steven Rostedt (Red Hat) 2015-05-28 17:36:45 -04:00 committed by Steven Rostedt
parent fcc742eaad
commit 9826b2733a
1 changed files with 25 additions and 16 deletions
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41
kernel/trace/ring_buffer.c
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@ -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);