Re: [PATCH 3/7] lockdep: lock contention tracking

[Peter Zijlstra]

On Wed, 2007-05-23 at 10:40 -0400, Jason Baron wrote:
> On Wed, 23 May 2007, Peter Zijlstra wrote:
> 
> > Count lock contention events per lock class. Additionally track the first four
> > callsites that resulted in the contention.
> > 
> 
> I think that we need the total number of locking calls, not just the total 
> number of *contended* locking calls, in order to make the data 
> significant. Same for waittime. Yes, this pollutes the fastpath. In the 
> contention case, its one extra addition, and for the waittime, its a call 
> the sched_clock(). I don't think that's too much to pay for much more 
> meaningful data.

The holdtime statistics add these numbers.

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