Re: [PATCH v3 2/3] perf: add arm64 smmuv3 pmu driver

[Jean-Philippe Brucker]

On 03/10/2018 09:46, Shameerali Kolothum Thodi wrote:
[...]
>>> +	/* Verify specified event is supported on this PMU */
>>> +	event_id = get_event(event);
>>> +	if (((event_id < SMMU_ARCH_MAX_EVENT_ID) &&
>>> +	    (!test_bit(event_id, smmu_pmu->supported_events))) ||
>>> +	    (event_id > SMMU_IMPDEF_MAX_EVENT_ID)) {
>>
>>> = ?
> 
> I was slightly confused by the spec here as it says,
> 
> Performance events are indicated by a numeric ID, in the following ranges:
> â 0x0000 to 0x007F: Architected events
> â 0x0080 to 0xFFFF: IMPLEMENTATION DEFINED events
> 
> It looks to me the ids are valid including those limits.

Yes my mistake, I mixed up IMPDEF_MAX_EVENT_ID which is inclusive with
ARCH_MAX_EVENT_ID which isn't, sorry about that

[...]
>>> +		dev_err(dev, "Setup irq failed, PMU @%pa\n", &res_0->start);
>>
>> You can probably remove "PMU @%pa" from error and info messages, since
>> the device name already uniquely identifies it:
>> "[    6.168200] arm-smmu-v3-pmu 2b442000.smmu-pmcg: Registered SMMU
>> PMU
>> @ 0x000000002b442000 using 4 counters"
> 
> Interesting. What I have is,
> 
> [   25.669636] arm-smmu-v3-pmu arm-smmu-v3-pmu.6.auto: Registered SMMU
> PMU @ 0x0000000148001000 using 8 counters
> 
> Are you using the same patches and is booting using ACPI? IIRC, in the iort
> code  it uses the name "arm-smmu-v3-pmu" and AUTO id to register/add the platform
> dev. So not sure, how it is printing the address in your case. 
> 
> Please check and let me know.

Right, I've been using device tree for my tests, not ACPI. I thought it
was the core platform code that was creating the names. I guess we could
add nicer names to IORT but that's probably for a different series, so
nevermind.

Thanks,
Jean