[PATCH v2 0/3] Arm CMN-600 PMU driver
Will Deacon
will at kernel.org
Mon Oct 5 06:21:15 EDT 2020
On Mon, Oct 05, 2020 at 09:16:13AM +0000, Zidenberg, Tsahi wrote:
>
>
> On 18/09/2020, 16:29, "Robin Murphy" <robin.murphy at arm.com> wrote:
> > Here's an update with some very minor cleanup tweaks, plus a proposal
> > for some more in-depth debug information. Given that nobody seems to
> > have any significant complaints about the interface, I assume we're all
> > happy to merge the basic driver as-is and fix anything later if needed.
> >
> > Robin.
>
> Agree with merging the driver as-is.
> Tested both the updated driver and the debugfs on Graviton2 (ACPI).
> Both map and initial numbers seem right.
>
> Tested-by: Tsahi Zidenberg <tsahee at amazon.com>
>
> May I offer a small addition to the documentation?
> Something along these lines:
>
> --- a/Documentation/admin-guide/perf/arm-cmn.rst
> +++ b/Documentation/admin-guide/perf/arm-cmn.rst
> @@ -41,8 +41,14 @@ specified by "occupid".
>
> By default each event provides an aggregate count over all nodes of the
> given type. To target a specific node, "bynodeid" must be set to 1 and
> -"nodeid" to the appropriate value derived from the CMN configuration
> -(as defined in the "Node ID Mapping" section of the TRM).
> +"nodeid" to the appropriate value derived from the CMN configuration.
> +
> +The CMN map is available in /sys/kernel/debug/arm-cmn/map.
> +A nodeid could be calculated with this formulae:
> + node-id = d | (p << 2) | (y << 3) | (x << (3 + xybits))
> +where:
> + x,y,p,d are node location as can be seen in the map
> + xybits is 2 for meshes <= 2*2, and 3 otherwise.
I already queued the driver, but if you send this as a stand-alone patch (on
top of the arm64 for-next/perf branch) then I'm happy to take it.
Thanks,
Will
> Watchpoints
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>
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