Re: [PATCH V10 0/6] Enable PMUs in ACPI Systems

[Punit Agrawal <punit.agrawal@arm.com>]

Hi Jeremy,

Jeremy Linton <jeremy.linton@arm.com> writes:

> This patch expands and reworks the patches published by Mark Salter
> in order to clean up a few of the previous review comments, as well as
> add support for newer CPUs and big/little configurations.
>
> v10:
> - Rebase to 4.9
> - Rework the arm_perf_start_cpu changes to support the 4.9 hotplug
>   changes.
> - Remove the call to acpi_register_gsi() from the cpu online code path.
>   Instead the GSI's are registered during the initcall. This changes
>   the error handling a bit because we now try to clean up the
>   previously registered GSIs in a couple important places. This
>   was also a result of the rebase.
> - Dropped the MIDR partnumber usage, its no longer necessary to
>   differentiate by only the partnum, so this helps to clarify the code
>   a bit. 
> - Shuffle some code around and rename a few variables.
> - Added a few comments to hopefully clarify some questions people have
>   previously had about unused MADT entries, skipping processing cores
>   with MIDR=0, etc.
>

I've had a look at the code and tested the patches on a Juno and a
Seattle based system I have and the pmus seem to be behaving themselves.

FWIW,

Acked-by: Punit Agrawal <punit.agrawal@arm.com>

Tested-by: Punit Agrawal <punit.agrawal@arm.com>

> v9:
> - Add/cleanup an additional hotplug patch I've had sitting around. This
>   patch brings the ACPI PMU mostly on par with the DT functionality with
>   respect to having CPUs offline during boot. This should help clarify
>   some of the code structuring.
> - Cleanup the list of PMU types early if we fail to allocate memory for an
>   additional pmu type.
>
> v8:
> - Rebase to 4.8rc4
> - Assorted minor comment/hunk placement/etc tweaks per Punit Agrawal
>
> v7:
> - Rebase to 4.8rc3
> - Remove cpu affinity sysfs entry. While providing a CPU mask for
>   ARMv8 PMU's is really helpful in big/little environments, reworking
>   the PMU code to support the cpumask attribute for !arm64 PMUs is out
>   of the scope of this patch set.
> - Fix CPU miscount problem where an alloc failure followed by successfully
>   allocating the structure can result in under counting the CPUs associated
>   with the PMU. This bug was created in v6 with the conversion to a linked
>   list.
> -  Remove initial platform device creation code by Mark Salter, and re-squash
>    multiple platform device creation code together with helper routines.
>    Other minor tweakage.
>
> v6:
> - Added cpu affinity sysfs entry
> - Converted pmu_types array, to linked list
> - Restrict use of the armv8_pmu_probe_table to ACPI systems
> - Rename MADT parsing routines in smp.c
> - Convert sysfs PMU name to use index rather than partnum
> - Remove pr_devel statements
> - Other Minor cleanups
> - Add Partial Ack-by Will Deacon
>
> v5:
> - Remove list of CPU types for ACPI systems. We now match a generic
>   event list, and use the PMCIED[01] to select events which exist on
>   the given PMU. This avoids the need to update the kernel every time
>   a new CPU is released.
> - Update the maintainers list to include the new file.
>
> v4:
> - Correct build issues with ARM (!ARM64) kernels.
> - Add ThunderX to list of PMU types.
>
> v3:
> - Enable ARM performance monitoring units on ACPI/arm64 machines.
>
> Jeremy Linton (5):
>   arm64: Rename the common MADT parse routine
>   arm: arm64: Add routine to determine cpuid of other cpus
>   arm: arm64: pmu: Assign platform PMU CPU affinity
>   arm64: pmu: Detect and enable multiple PMUs in an ACPI system
>   arm: pmu: Add PMU definitions for cores not initially online
>
> Mark Salter (1):
>   arm64: pmu: Cache PMU interrupt numbers from MADT parse
>
>  arch/arm/include/asm/cputype.h   |   2 +
>  arch/arm64/include/asm/cputype.h |   3 +
>  arch/arm64/kernel/smp.c          |  18 ++-
>  drivers/perf/Kconfig             |   4 +
>  drivers/perf/Makefile            |   1 +
>  drivers/perf/arm_pmu.c           | 107 +++++++++++++--
>  drivers/perf/arm_pmu_acpi.c      | 272 +++++++++++++++++++++++++++++++++++++++
>  include/linux/perf/arm_pmu.h     |  11 ++
>  8 files changed, 400 insertions(+), 18 deletions(-)
>  create mode 100644 drivers/perf/arm_pmu_acpi.c