diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-05-12 21:20:48 +0200 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2008-05-23 20:54:37 +0200 |
commit | 0fd9e0dac9026df09986a4b201518ae015814aef (patch) | |
tree | bbc20440973ac0196818a9a1b91fde17148fd8fd /kernel/trace/trace.c | |
parent | 26994ead1fc8cced63f17e9848edc1771036664e (diff) |
ftrace: use cpu clock again
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r-- | kernel/trace/trace.c | 54 |
1 files changed, 1 insertions, 53 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 3dc6eac85b1..d74c039305a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -42,61 +42,9 @@ ns2usecs(cycle_t nsec) return nsec; } -static const int time_sync_freq_max = 128; -static const cycle_t time_sync_thresh = 100000; - -static DEFINE_PER_CPU(cycle_t, time_offset); -static DEFINE_PER_CPU(cycle_t, prev_cpu_time); -static DEFINE_PER_CPU(int, time_sync_count); -static DEFINE_PER_CPU(int, time_sync_freq); - -/* - * Global lock which we take every now and then to synchronize - * the CPUs time. This method is not warp-safe, but it's good - * enough to synchronize slowly diverging time sources and thus - * it's good enough for tracing: - */ -static DEFINE_SPINLOCK(time_sync_lock); -static cycle_t prev_global_time; - -static notrace cycle_t __ftrace_now_sync(cycles_t time, int cpu) -{ - unsigned long flags; - - spin_lock_irqsave(&time_sync_lock, flags); - - /* - * Update the synchronization frequency: - */ - if (per_cpu(time_sync_freq, cpu) < time_sync_freq_max) - per_cpu(time_sync_freq, cpu) *= 2; - per_cpu(time_sync_count, cpu) = per_cpu(time_sync_freq, cpu); - - if (time < prev_global_time) { - per_cpu(time_offset, cpu) += prev_global_time - time; - time = prev_global_time; - } else { - prev_global_time = time; - } - - spin_unlock_irqrestore(&time_sync_lock, flags); - - return time; -} - notrace cycle_t ftrace_now(int cpu) { - cycle_t prev_cpu_time, time, delta_time; - - prev_cpu_time = per_cpu(prev_cpu_time, cpu); - time = sched_clock() + per_cpu(time_offset, cpu); - delta_time = time-prev_cpu_time; - - if (unlikely(delta_time > time_sync_thresh || - --per_cpu(time_sync_count, cpu) <= 0)) - time = __ftrace_now_sync(time, cpu); - - return time; + return cpu_clock(cpu); } static struct trace_array global_trace; |