[RFC PATCH 00/15] ARM: perf: support multiple PMUs

[Ashwin Chaugule]

>> -----Original Message-----
>> From: Mark Rutland
>> System (AKA nest or uncore) PMUs exist on devices which are not affine
>> to a single CPU. They usually cannot be directly associated with
>> individual tasks and are asynchronous with respect to the current
>> execution. Examples of devices which could have system PMUs include L2
>> cache controllers, GPUs and memory buses.
>>
>> The following patch series refactors the ARM PMU backend, enabling
>> new PMUs to reuse the existing code. This should allow for system PMUs
>> to be supported in future. Further work will be required to get perf to
>> fully understand system PMUs, but this provides something usable.
>>
>> The framework is intended to be used by system PMUs which hang off core
>> platform components (e.g. L2 cache, AXI bus). If a device is complex
>> enough or separate enough from core functionality to have its own
>> driver, it should implement its own PMU handling using the core perf
>> API directly.
>>
>> The first patch ("perf: provide PMU when initing events") is currently
>> sitting in the tip tree, but as it's required for event initialization
>> to function (and hence for the PMU to be usable), it's provided here
>> for convenience.
>>
>> The series is based on Will Deacon's perf-updates branch at:
>> 	git://linux-arm.org/linux-2.6-wd.git perf-updates
>>
>> An example driver using the framework (supporting the PMU present in
>> L220/PL310 level 2 cache controllers) can be found at:
>> 	git://linux-arm.org/linux-2.6-wd.git perf-l2x0-wip
>>
>> Any comments would be welcome.
>>
>> Thanks,
>> Mark.
>

Other than the comments on patch [05/15] and [08/15], this series looks
good to me !

Reviewed-by: Ashwin Chaugule <ashwinc at codeaurora.org>


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