Re: [PATCH v5 00/10] drivers/perf: CPU PMU driver for Apple M1

From: Marc Zyngier
Date: Mon Mar 07 2022 - 10:55:52 EST


On Tue, 08 Feb 2022 18:55:54 +0000,
Marc Zyngier <maz@xxxxxxxxxx> wrote:
>
> The M1 SoC embeds a per-CPU PMU that has a very different programming
> interface compared to the architected PMUv3 that is normally present
> on standard implementations.
>
> This small series adds a driver for this HW by leveraging the arm_pmu
> infrastructure, resulting in a rather simple driver.
>
> Of course, we know next to nothing about the actual events this PMU
> counts, aside from CPU cycles and instructions. Everything else is
> undocumented (though as Dougall pointed out, someone could extract the
> relevant information from a macOS install if they wanted -- I don't).
> I'm looking at allowing the perf userspace tool to load the event
> descriptions at runtime, which would probably help.

[...]

FWIW, I have created two branches:

- [1] has the full series
- [2] has the irqchip/DT prefix of [1]

Both branches are stable, and I expect [2] to be used as a shared
branch between the irqchip and perf trees.

Thanks,

M.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=hack/m1-pmu
[2] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=irq/aic-pmu

--
Without deviation from the norm, progress is not possible.