Messages in this thread | | | Subject | Re: [[PATCH v6 02/10] perf: Add a flags parameter to pmu txn interfaces | From | Michael Ellerman <> | Date | Fri, 04 Sep 2015 20:07:29 +1000 |
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On Thu, 2015-09-03 at 20:07 -0700, Sukadev Bhattiprolu wrote: > Currently, the PMU interface allows reading only one counter at a time. > But some PMUs like the 24x7 counters in Power, support reading several > counters at once. To leveage this functionality, extend the transaction > interface to support a "transaction type". > > The first type, PERF_PMU_TXN_ADD, refers to the existing transactions, > i.e. used to _schedule_ all the events on the PMU as a group. A second > transaction type, PERF_PMU_TXN_READ, will be used in a follow-on patch, > by the 24x7 counters to read several counters at once. > > Extend the transaction interfaces to the PMU to accept a 'txn_flags' > parameter and use this parameter to ignore any transactions that are > not of type PERF_PMU_TXN_ADD. > > Thanks to Peter Zijlstra for his input. > > Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> > > --- > arch/powerpc/perf/core-book3s.c | 30 +++++++++++++++++++++++++++++-
These powerpc changes look OK to me.
So for those you can have an:
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Having said that, we do end up repeating a lot of boiler plate for each arch, which is a pity. eg:
> +static void power_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags) > { > struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events); > > + WARN_ON_ONCE(cpuhw->txn_flags); /* txn already in flight */ > + > + cpuhw->txn_flags = txn_flags; > + if (txn_flags & ~PERF_PMU_TXN_ADD) > + return; > +
And so on.
But I can't think of an easy way to avoid that, so it's not a blocker, but maybe someone can think of a nice solution to avoid it?
cheers
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