Re: [PATCH 10/11] tracing/perf: Fix lock events recursions in thefast path

[Peter Zijlstra]

On Sat, 2010-02-06 at 17:10 +0100, Frederic Weisbecker wrote:
> 
> > > Looks pretty what I'm looking for. Except that it still continues
> > > to fill and keep track of the locks held by the current thread,
> > > namely the copies in curr->held_locks.
> > 
> > Which is exactly what you need for that lock hierarchy recording you
> > wanted :-)
> 
> 
> Well, the lock hierarchy should probably be retrieved from the traces,
> using state machines.
> Otherwise we would need yet other lock events for that, which is going
> to add even more overhead.


Right, well you could look at adding a mode that also strips out the
held_lock tracing, but since you really need the register class stuff to
re-generate the class mapping, avoiding the held_lock tracing doesn't
look like it's going to save you much, its all thread local storage.

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