Messages in this thread Patch in this message | | | Date | Mon, 11 Jan 2016 10:54:54 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH v5 08/11] arm-cci: Provide hook for writing to PMU counters |
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On Mon, Jan 04, 2016 at 11:54:47AM +0000, Suzuki K. Poulose wrote: > Add a hook for writing to CCI PMU counters. This callback > can be used for CCI models which requires some extra work > to program the PMU counter values. To accommodate group writes > and single counter writes, the call back accepts a bitmask > of the counter indices which need to be programmed with the > given value. > > Cc: Punit Agrawal <punit.agrawal@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com> > --- > drivers/bus/arm-cci.c | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c > index 2f1fcf0..47c9581 100644 > --- a/drivers/bus/arm-cci.c > +++ b/drivers/bus/arm-cci.c > @@ -134,6 +134,7 @@ struct cci_pmu_model { > struct event_range event_ranges[CCI_IF_MAX]; > int (*validate_hw_event)(struct cci_pmu *, unsigned long); > int (*get_event_idx)(struct cci_pmu *, struct cci_pmu_hw_events *, unsigned long); > + void (*write_counters)(struct cci_pmu *, unsigned long *, u32 val); > }; > > static struct cci_pmu_model cci_pmu_models[]; > @@ -846,7 +847,15 @@ static void pmu_write_counter(struct perf_event *event, u32 value) > dev_err(&cci_pmu->plat_device->dev, "Invalid CCI PMU counter %d\n", idx); > return; > } > - __pmu_write_counter(cci_pmu, value, idx); > + > + if (cci_pmu->model->write_counters) { > + unsigned long mask[BITS_TO_LONGS(cci_pmu->num_cntrs)]; > + > + memset(mask, 0, BITS_TO_LONGS(cci_pmu->num_cntrs) * sizeof(unsigned long)); > + set_bit(idx, mask); > + cci_pmu->model->write_counters(cci_pmu, mask, value); > + } else > + __pmu_write_counter(cci_pmu, value, idx); > }
It would be much simpler to always log writes here, and only do the real wirtes in batches when we re-enable the PMU (with appropriate disable/enable calls in the IRQ handler).
We'd still need special hooks for CCIs which require a special dance to program them, but all the logic to handle the writes would be in one place.
This should work, regardless.
Thanks, Mark.
> > /* Write a value to a given set of counters */ > @@ -861,7 +870,10 @@ static void __pmu_write_counters(struct cci_pmu *cci_pmu, unsigned long *mask, u > static void __maybe_unused > pmu_write_counters(struct cci_pmu *cci_pmu, unsigned long *mask, u32 value) > { > - __pmu_write_counters(cci_pmu, mask, value); > + if (cci_pmu->model->write_counters) > + cci_pmu->model->write_counters(cci_pmu, mask, value); > + else > + __pmu_write_counters(cci_pmu, mask, value); > } > > static u64 pmu_event_update(struct perf_event *event) > -- > 1.7.9.5 >
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