Messages in this thread | | | Subject | Re: [PATCH 10/11] tracing/perf: Fix lock events recursions in the fast path | From | Peter Zijlstra <> | Date | Sat, 06 Feb 2010 15:17:47 +0100 |
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On Sat, 2010-02-06 at 12:40 +0100, Frederic Weisbecker wrote: > On Sat, Feb 06, 2010 at 12:24:02PM +0100, Peter Zijlstra wrote: > > On Sat, 2010-02-06 at 12:12 +0100, Frederic Weisbecker wrote: > > > > > That said, I think this is good for a first step, but we can't continue > > > to force the lock events -> lockdep dependency in the long term. We > > > can't have a serious lock profiling if we are doomed to suffer the > > > slowness due to lockdep checks at the same time. > > > > > > Sure we can continue to support having both, but I think we should also > > > think about a solution to handle lock events without it in the future. > > > That will require some minimal lockdep functionalities (keeping the > > > lockdep map, and class hashes). > > > > You mean like building without CONFIG_PROVE_LOCKING, or boot with > > lockdep.prove_locking=0, or use echo 0 > > > /sys/modules/lockdep/prove_locking ? > > > > That keeps the lock tracking but does away with all the dependency > > analysis and was created for just such an use case as you are looking > > at, namely lockstat. > > > 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 :-)
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