Prev: Tracing of power:power_start events doesn't work
Next: futex: futex_find_get_task make credentials check conditional
From: Peter Zijlstra on 29 Jun 2010 12:40 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(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Peter Zijlstra on 29 Jun 2010 14:10 On Tue, 2010-06-29 at 20:07 +0200, Frederic Weisbecker wrote: > On Tue, Jun 29, 2010 at 06:34:10PM +0200, Peter Zijlstra wrote: > > On Tue, 2010-06-29 at 17:03 +0200, Frederic Weisbecker wrote: > > > > You mean, if (!pmu->start_txn && pmu->pmu_enable) { /* install defaults > > > > */ } ? > neglected pmu implementations shouldn't impact software pmus. With the above and not providing ->pmu_enable you get that. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Frederic Weisbecker on 29 Jun 2010 14:10 On Tue, Jun 29, 2010 at 06:34:10PM +0200, Peter Zijlstra wrote: > 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. In this case, archs should handle that by implementing their txn. neglected pmu implementations shouldn't impact software pmus. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Peter Zijlstra on 29 Jun 2010 14:20 On Tue, 2010-06-29 at 20:11 +0200, Frederic Weisbecker wrote: > On Tue, Jun 29, 2010 at 08:09:10PM +0200, Peter Zijlstra wrote: > > On Tue, 2010-06-29 at 20:07 +0200, Frederic Weisbecker wrote: > > > On Tue, Jun 29, 2010 at 06:34:10PM +0200, Peter Zijlstra wrote: > > > > On Tue, 2010-06-29 at 17:03 +0200, Frederic Weisbecker wrote: > > > > > > You mean, if (!pmu->start_txn && pmu->pmu_enable) { /* install defaults > > > > > > */ } ? > > > > > neglected pmu implementations shouldn't impact software pmus. > > > > With the above and not providing ->pmu_enable you get that. > > > But we don't need to provide a pmu_enable for software events, right? My point exactly. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Frederic Weisbecker on 29 Jun 2010 14:20 On Tue, Jun 29, 2010 at 08:09:10PM +0200, Peter Zijlstra wrote: > On Tue, 2010-06-29 at 20:07 +0200, Frederic Weisbecker wrote: > > On Tue, Jun 29, 2010 at 06:34:10PM +0200, Peter Zijlstra wrote: > > > On Tue, 2010-06-29 at 17:03 +0200, Frederic Weisbecker wrote: > > > > > You mean, if (!pmu->start_txn && pmu->pmu_enable) { /* install defaults > > > > > */ } ? > > > neglected pmu implementations shouldn't impact software pmus. > > With the above and not providing ->pmu_enable you get that. But we don't need to provide a pmu_enable for software events, right? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
First
|
Prev
|
Next
|
Last
Pages: 1 2 3 Prev: Tracing of power:power_start events doesn't work Next: futex: futex_find_get_task make credentials check conditional |