Re: Lock dependency based tree report in perf lock

[Frederic Weisbecker]

On Sat, Jan 30, 2010 at 09:46:28AM +0100, Peter Zijlstra wrote:
> On Sat, 2010-01-30 at 00:17 +0100, Frederic Weisbecker wrote:
> > 
> > 
> > Anyway, that's just an idea, not trivial I must admit.
> 
> lockdep actually collects all this information, so writing it out isn't
> too hard.



Lockdep collects the theorical dependencies but not the practical
scenarios.

Say B and C depend on A, you'll get:

   A
  / \
 B   C

But nothing can tell you that if A is taken, B and C will always
be taken. You may have different scenarios based on this dependency,
which is not something that lockdep logs, right?

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