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

[Agustin Vega-Frias <agustinv@codeaurora.org>]

On 2018-04-02 02:37, Yisheng Xie wrote:
> Hi Neil,
> 
> On 2018/4/1 13:44, Neil Leeder wrote:
>> Hi Yisheng Xie,
>> 
>> On 3/29/2018 03:03 AM, Yisheng Xie wrote:
>>> 
>>> Hi Neil,
>>> 
>>> On 2017/8/5 3:59, Neil Leeder wrote:
>>>> +    mem_resource_0 = platform_get_resource(pdev, IORESOURCE_MEM, 
>>>> 0);
>>>> +    mem_map_0 = devm_ioremap_resource(&pdev->dev, mem_resource_0);
>>>> +
>>> Can we use devm_ioremap instead? for the reg_base of smmu_pmu is
>>> IMPLEMENTATION DEFINED. If the reg of smmu_pmu is inside smmu,
>>> devm_ioremap_resource will failed and return -EBUSY, eg.:
>>> 
>>>   smmu reg ranges:        0x180000000 ~ 0x1801fffff
>>>   its smmu_pmu reg ranges:    0x180001000 ~ 0x180001fff
>>> 
>> Just to let you know that I no longer work at Qualcomm and I won't be 
>> able to provide updates to this patchset. I expect that others from my 
>> former team at Qualcomm will pick up ownership.
> 
> Thanks for this infomation.
> 
> hi Agustin and Timur,
> 
> Is there any new status about this patchset?
> 

Hi,

Apologies for the slow response.
We are having some internal discussions about when/if to do this.
I expect to have more clarity within a few weeks.

For what is worth let me take the opportunity to outline the approach
we would like to see for a V2 either developed by us or somebody else
in the community:

1. Rework to comply with the IORT spec changes.

2. Rework probing to extract extra information from the IORT table
    about SMMU/device associations.

   With this information and some perf user space work I think it's 
possible
   to have a single dynamic PMU node and use a similar approach to what 
is
   used in the Coresight drivers to pass the device we want to monitor 
and
   for the driver to find the PMU/PMCG. E.g.:

   $ lspci
   0001:00:00.0 PCI bridge: Airgo Networks, Inc. Device 0401
   0002:00:00.0 PCI bridge: Airgo Networks, Inc. Device 0401
   0002:01:00.0 Ethernet controller: Mellanox Technologies MT27500 Family 
[ConnectX-3]
   0003:00:00.0 PCI bridge: Airgo Networks, Inc. Device 0401
   0003:01:00.0 Ethernet controller: Mellanox Technologies MT27500 Family 
[ConnectX-3]

   # Monitor TLB misses on root complex 2 (no stream filter is applied)
   perf stat -a -e smmu/tlb_miss,@0002:00:00.0/ <workload>

   # Monitor TLB misses on a device on root complex 2 (derive the stream 
number from the RID)
   perf stat -a -e smmu/tlb_miss,@0002:01:00.0/ <workload>

Thanks,
Agustín

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