Re: [PATCH v7 0/4] Add perf interface to expose nvdimm

From: Madhavan Srinivasan
Date: Mon Mar 07 2022 - 02:21:25 EST



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 <maddy@xxxxxxxxxx>


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-lkp@xxxxxxxxx/

- 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