[PATCH v4 0/4] Add perf interface to expose nvdimm

From: Kajol Jain
Date: Mon Aug 02 2021 - 03:40:35 EST


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 supported events, cpumask
pmu event functions like event_init/add/read/del.
User could use the standard perf tool to access perf
events exposed via pmu.

Added implementation to expose IBM pseries platform nmem*
device performance stats using this interface.

Result from power9 pseries lpar with 2 nvdimm device:
command:# perf list nmem
nmem0/cchrhcnt/ [Kernel PMU event]
nmem0/cchwhcnt/ [Kernel PMU event]
nmem0/critrscu/ [Kernel PMU event]
nmem0/ctlresct/ [Kernel PMU event]
nmem0/ctlrestm/ [Kernel PMU event]
nmem0/fastwcnt/ [Kernel PMU event]
nmem0/hostlcnt/ [Kernel PMU event]
nmem0/hostldur/ [Kernel PMU event]
nmem0/hostscnt/ [Kernel PMU event]
nmem0/hostsdur/ [Kernel PMU event]
nmem0/medrcnt/ [Kernel PMU event]
nmem0/medrdur/ [Kernel PMU event]
nmem0/medwcnt/ [Kernel PMU event]
nmem0/medwdur/ [Kernel PMU event]
nmem0/memlife/ [Kernel PMU event]
nmem0/noopstat/ [Kernel PMU event]
nmem0/ponsecs/ [Kernel PMU event]
nmem1/cchrhcnt/ [Kernel PMU event]
nmem1/cchwhcnt/ [Kernel PMU event]
nmem1/critrscu/ [Kernel PMU event]
...
nmem1/noopstat/ [Kernel PMU event]
nmem1/ponsecs/ [Kernel PMU event]

Patch1:
Introduces the nvdimm_pmu structure
Patch2:
Adds common interface to add arch/platform specific data
includes supported events, pmu event functions. 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 event attrs
cpumask andevent functions and then registers the pmu by adding
callbacks to register_nvdimm_pmu.
Patch4:
Sysfs documentation patch

Changelog
---
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
powerpc/papr_scm: Document papr_scm sysfs event format entries

Documentation/ABI/testing/sysfs-bus-papr-pmem | 31 ++
arch/powerpc/include/asm/device.h | 5 +
arch/powerpc/platforms/pseries/papr_scm.c | 365 ++++++++++++++++++
drivers/nvdimm/Makefile | 1 +
drivers/nvdimm/nd_perf.c | 230 +++++++++++
include/linux/nd.h | 46 +++
6 files changed, 678 insertions(+)
create mode 100644 drivers/nvdimm/nd_perf.c

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2.26.2