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

[Agustin Vega-Frias]

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,
AgustÃn

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