Re: [RFC][PATCH 09/11] perf: Default PMU ops

[Peter Zijlstra]

On Tue, 2010-06-29 at 17:03 +0200, Frederic Weisbecker wrote:
> > You mean, if (!pmu->start_txn && pmu->pmu_enable) { /* install defaults
> > */ } ?
> 
> 
> Not really. pmu_*able and txn are there for different purposes.
> A pmu implementation may want to provide enable/disable things
> but not require any txn. Or one may just not need any of those,
> like software events.
> 
> It should simply map to a nop if nothing is provided. 

Thing is, using at least the pmu_enable/disable fallback when no txn
methods are provided can save bunch of hardware writes. So this trivial
fallback makes sense.


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/