Re: [PATCH v5 0/7] arm64: perf: Support for chained counters

From: Will Deacon
Date: Tue Jul 10 2018 - 10:30:28 EST


Hi Suzuki,

On Tue, Jul 10, 2018 at 09:57:57AM +0100, Suzuki K Poulose wrote:
> This series adds support for counting PMU events using 64bit counters
> for arm64 PMU.
>
> The Arm v8 PMUv3 supports combining two adjacent 32bit counters
> (low even and hig odd counters) to count a given "event" in 64bit mode.
> This series adds the support for 64bit events in the core arm_pmu driver
> infrastructure and adds the support for armv8 64bit kernel PMU to use
> chained counters to count in 64bit mode. For CPU cycles, we use the cycle
> counter in 64bit mode, only when requested. If the cycle counter is not
> available, we fall back to chaining the counters.
>
> Tested on Juno, Fast models. Applies on 4.18-rc4

Thanks, this looks pretty good to me. How far did you get with the perf
fuzzer?

Will