Messages in this thread | | | Subject | Re: [PATCH v2 3/5] arm_pmu: Add support for 64bit event counters | From | Suzuki K Poulose <> | Date | Thu, 7 Jun 2018 08:34:40 +0100 |
| |
On 06/06/2018 05:48 PM, Mark Rutland wrote: > On Tue, May 29, 2018 at 11:55:54AM +0100, Suzuki K Poulose wrote: >> Each PMU has a set of 32bit event counters. But in some >> special cases, the events could be counted using counters >> which are effectively 64bit wide. >> >> e.g, Arm V8 PMUv3 has a 64 bit cycle counter which can count >> only the CPU cycles. Also, the PMU can chain the event counters >> to effectively count as a 64bit counter. >> >> Add support for tracking the events that uses 64bit counters. >> This only affects the periods set for each counter in the core >> driver. >> >> Cc: Mark Rutland <mark.rutland@arm.com> >> Cc: Will Deacon <will.deacon@arm.com> >> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> >> --- >> Changes since v1: >> - Rename ARMPMU_EVT_LONG => ARMPMU_EVT_64BIT >> --- >> drivers/perf/arm_pmu.c | 14 ++++++++------ >> include/linux/perf/arm_pmu.h | 6 ++++++ >> 2 files changed, 14 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c >> index 8962d26..ff858e6 100644 >> --- a/drivers/perf/arm_pmu.c >> +++ b/drivers/perf/arm_pmu.c >> @@ -28,9 +28,10 @@ >> static DEFINE_PER_CPU(struct arm_pmu *, cpu_armpmu); >> static DEFINE_PER_CPU(int, cpu_irq); >> >> -static inline u64 arm_pmu_max_period(void) >> +static inline u64 arm_pmu_event_max_period(struct perf_event *event) >> { >> - return (1ULL << 32) - 1; >> + return (event->hw.flags & ARMPMU_EVT_64BIT) ? >> + ~0ULL : (1ULL << 32) - 1; >> } > > Could we please have: > > static inline u64 arm_pmu_event_max_period(struct perf_event *event) > { > if (event->hw.flags & ARMPMU_EVT_64BIT) > return GENMASK_ULL(63, 0); > else > return GENMASK_ULL(31, 0); > } > > ... since that's obviously balanced, with both values generated in the > same way. >
Sure, will do
Suzuki
| |