Skip to content

Commit

Permalink
---
Browse files Browse the repository at this point in the history
yaml
---
r: 100464
b: refs/heads/master
c: 0fd9e0d
h: refs/heads/master
v: v3
  • Loading branch information
Ingo Molnar authored and Thomas Gleixner committed May 23, 2008
1 parent 373352e commit a8d1dca
Show file tree
Hide file tree
Showing 2 changed files with 2 additions and 54 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 26994ead1fc8cced63f17e9848edc1771036664e
refs/heads/master: 0fd9e0dac9026df09986a4b201518ae015814aef
54 changes: 1 addition & 53 deletions trunk/kernel/trace/trace.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down

0 comments on commit a8d1dca

Please sign in to comment.