On 2/25/22 20:00, Kajol Jain wrote:
Patchset adds performance stats reporting support for nvdimm.
Added interface includes support for pmu register/unregister
functions. A structure is added called nvdimm_pmu to be used for
adding arch/platform specific data such as cpumask, nvdimm device
pointer and pmu event functions like event_init/add/read/del.
User could use the standard perf tool to access perf events
exposed via pmu.

Interface also defines supported event list, config fields for the
event attributes and their corresponding bit values which are exported
via sysfs. Patch 3 exposes IBM pseries platform nmem* device
performance stats using this interface.

Result from power9 pseries lpar with 2 nvdimm device:

Patchset looks fine to me.

Reviewed-by: Madhavan Srinivasan <ma...@in.ibm.com>


Ex: List all event by perf list

command:# perf list nmem

   nmem0/cache_rh_cnt/                                [Kernel PMU event]
   nmem0/cache_wh_cnt/                                [Kernel PMU event]
   nmem0/cri_res_util/                                [Kernel PMU event]
   nmem0/ctl_res_cnt/                                 [Kernel PMU event]
   nmem0/ctl_res_tm/                                  [Kernel PMU event]
   nmem0/fast_w_cnt/                                  [Kernel PMU event]
   nmem0/host_l_cnt/                                  [Kernel PMU event]
   nmem0/host_l_dur/                                  [Kernel PMU event]
   nmem0/host_s_cnt/                                  [Kernel PMU event]
   nmem0/host_s_dur/                                  [Kernel PMU event]
   nmem0/med_r_cnt/                                   [Kernel PMU event]
   nmem0/med_r_dur/                                   [Kernel PMU event]
   nmem0/med_w_cnt/                                   [Kernel PMU event]
   nmem0/med_w_dur/                                   [Kernel PMU event]
   nmem0/mem_life/                                    [Kernel PMU event]
   nmem0/poweron_secs/                                [Kernel PMU event]
   ...
   nmem1/mem_life/                                    [Kernel PMU event]
   nmem1/poweron_secs/                                [Kernel PMU event]

Patch1:
         Introduces the nvdimm_pmu structure
Patch2:
         Adds common interface to add arch/platform specific data
         includes nvdimm device pointer, pmu data along with
         pmu event functions. It also defines supported event list
         and adds attribute groups for format, events and cpumask.
         It also adds code for cpu hotplug support.
Patch3:
         Add code in arch/powerpc/platform/pseries/papr_scm.c to expose
         nmem* pmu. It fills in the nvdimm_pmu structure with pmu name,
         capabilities, cpumask and event functions and then registers
         the pmu by adding callbacks to register_nvdimm_pmu.
Patch4:
         Sysfs documentation patch

Changelog
---
v6 -> v7
- Add function call to numa_map_to_online_node function inorder to
   get online numa node. As the node id returned by function dev_to_node
   can be offline in some scenarios and can create issue in hotplug code
   as reported by Nageswara R Sastry.

- Add function declaration of perf_pmu_register, perf_pmu_unregister
   and  perf_pmu_migrate_context functions in nd.h file to resolve
   the implicit-function-declaration warning as reported by kernel test
   robot.
   Link: https://lore.kernel.org/all/202202241242.zqzgkguy-...@intel.com/

- Add Tested-by, Acked-by and Reported-by tags from Peter Zijlstra
   and Nageswara R Sastry.

- Link to the patchset v6: https://lkml.org/lkml/2022/2/17/857

Resend v5 -> v6
- No logic change, just a rebase to latest upstream and
   tested the patchset.

- Link to the patchset Resend v5: https://lkml.org/lkml/2021/11/15/3979

v5 -> Resend v5
- Resend the patchset

- Link to the patchset v5: https://lkml.org/lkml/2021/9/28/643

v4 -> v5:
- Remove multiple variables defined in nvdimm_pmu structure include
   name and pmu functions(event_int/add/del/read) as they are just
   used to copy them again in pmu variable. Now we are directly doing
   this step in arch specific code as suggested by Dan Williams.

- Remove attribute group field from nvdimm pmu structure and
   defined these attribute groups in common interface which
   includes format, event list along with cpumask as suggested by
   Dan Williams.
   Since we added static defination for attrbute groups needed in
   common interface, removes corresponding code from papr.

- Add nvdimm pmu event list with event codes in the common interface.

- Remove Acked-by/Reviewed-by/Tested-by tags as code is refactored
   to handle review comments from Dan.

- Make nvdimm_pmu_free_hotplug_memory function static as reported
   by kernel test robot, also add corresponding Reported-by tag.

- Link to the patchset v4: https://lkml.org/lkml/2021/9/3/45

v3 -> v4
- Rebase code on top of current papr_scm code without any logical
   changes.

- Added Acked-by tag from Peter Zijlstra and Reviewed by tag
   from Madhavan Srinivasan.

- Link to the patchset v3: https://lkml.org/lkml/2021/6/17/605

v2 -> v3
- Added Tested-by tag.

- Fix nvdimm mailing list in the ABI Documentation.

- Link to the patchset v2: https://lkml.org/lkml/2021/6/14/25

v1 -> v2
- Fix hotplug code by adding pmu migration call
   incase current designated cpu got offline. As
   pointed by Peter Zijlstra.

- Removed the retun -1 part from cpu hotplug offline
   function.

- Link to the patchset v1: https://lkml.org/lkml/2021/6/8/500

Kajol Jain (4):
   drivers/nvdimm: Add nvdimm pmu structure
   drivers/nvdimm: Add perf interface to expose nvdimm performance stats
   powerpc/papr_scm: Add perf interface support
   docs: ABI: sysfs-bus-nvdimm: Document sysfs event format entries for
     nvdimm pmu

  Documentation/ABI/testing/sysfs-bus-nvdimm |  35 +++
  arch/powerpc/include/asm/device.h          |   5 +
  arch/powerpc/platforms/pseries/papr_scm.c  | 225 ++++++++++++++
  drivers/nvdimm/Makefile                    |   1 +
  drivers/nvdimm/nd_perf.c                   | 328 +++++++++++++++++++++
  include/linux/nd.h                         |  44 +++
  6 files changed, 638 insertions(+)
  create mode 100644 drivers/nvdimm/nd_perf.c


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