On Sun, 22 Sep 2002, Karim Yaghmour wrote:
> Ingo Molnar wrote:
> > +int trace_event(u8 pm_event_id,
> > + void *pm_event_struct)
> > [...]
> > + read_lock(&tracer_register_lock);
> >
> > ie. it's using a global spinlock. (sure, it can be made lockless, as other
> > tracers have done it.)
>
> It is, but this is separate from the trace driver. [...]
it does not matter, it's called for every event.
> [...] This global spinlock is only used to avoid a race condition in the
> registration/ unregistration of the tracing function with the trace
> infrastructure.
(here you make the incorrect assumption that read-locking a rwlock is a
lightweight operation.)
Ingo
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This archive was generated by hypermail 2b29 : Mon Sep 23 2002 - 22:00:37 EST