Ok, so correct me if I'm wrong.
Global timestamp would be captured by using sched_clock().
That's what is done currently in ring_buffer_time_stamp()
And the global timestamp would be combination of a last global
timestamp and a relative position from now to this last at
each insertion in the ring-buffer (or tracing time capture). Am I right?
I don't really understand why you want to update with a cmpxchg loop...
And the local timestamp would be built through cpu_clock() with
absolute values at each captures? Because we can't consider
relative values since this is loosing sense between cpu. Unless we
have per_cpu relative values.....
Then, depending of the current_tracer, ring_buffer_time_stamp would
act as a wrapper:
if (current_tracer->time_flag == TIME_GLOBAL_COHERENT)
return ring_buffer_global_timestamp();
else
return ring_buffer_local_timestamp();
Or more efficient with a function pointer set at the same we change
the time flag for the current tracer.
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