Re: [PATCH v5 00/24] ARM64 PMU Partitioning

Oliver Upton
2025-12-09T23:01:02Z

On Tue, Dec 09, 2025 at 08:50:57PM +0000, Colton Lewis wrote:
> This series creates a new PMU scheme on ARM, a partitioned PMU that
> allows reserving a subset of counters for more direct guest access,
> significantly reducing overhead. More details, including performance
> benchmarks, can be read in the v1 cover letter linked below.
>
> An overview of what this series accomplishes was presented at KVM
> Forum 2025. Slides [1] and video [2] are linked below.
>
> The long duration between v4 and v5 is due to time spent on this
> project being monopolized preparing this feature for internal
> production. As a result, there are too many improvements to fully list
> here, but I will cover the notable ones.

Thanks for reposting. I think there's still quite a bit of ground to
cover on the KVM side of this, but I would definitely appreciate it if
someone with more context on the perf side of things could chime in.

Will, IIRC you had some thoughts around counter allocation, right?

Best,
Oliver