Re: [PATCH RFC] perf lock: Add new event "lock_acquired_waittime"for contention analysis

From: Peter Zijlstra
Date: Mon Aug 02 2010 - 08:24:23 EST


On Sun, 2010-08-01 at 14:36 +0900, Hitoshi Mitake wrote:
> I want to make lockdep production kernel feature with dynamic
> patching.

Not really feasible. Note that enabling lockdep grows the size of
spinlock_t (and others) quite significantly.

Then there is the problem that you need to pass all tasks through some
quiesent state in order to enable lockdep (there must be a guarantee of
no locks held).

Now, we could possibly make it all work, but I'm not at all convinced we
want to pay the price, which is a much _much_ more complex
infrastructure.

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