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

From: Jason Baron
Date: Wed May 23 2007 - 11:01:23 EST



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.

thanks,

-Jason
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