[RFC 0/4] Add perf interface to expose nvdimm performance stats

Patchset adds performance stats reporting support for nvdimm. Added interface includes support for a pmu register function and callbacks to be used by arch/platform specific drivers. User could use standard perf tool to access perf events exposed via pmu. Patchset adds a structure called nvdimm_pmu which can be used to add platform specific data like supported event list and callbacks to pmu functions like event_init/add/delete/read. Patchset includes an implements the 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, common function for pmu register along with callback routine check. Pacth2 Add code in arch/powerpc/platform/pseries/papr_scm.c to expose nmem* pmu. It fills in the nvdimm_pmu structure with event attrs and event callback functions and then registers the pmu by adding callback to register_nvdimm_pmu. Patch3: Sysfs documentation patch Patch4: Adds cpuhotplug support. Kajol Jain (4): 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 powerpc/papr_scm: Add cpu hotplug support for nvdimm pmu device Documentation/ABI/testing/sysfs-bus-papr-pmem | 31 ++ arch/powerpc/include/asm/device.h | 5 + arch/powerpc/platforms/pseries/papr_scm.c | 346 +++++++++++++++++- drivers/nvdimm/Makefile | 1 + drivers/nvdimm/nd_perf.c | 111 ++++++ include/linux/nd.h | 31 ++ 6 files changed, 524 insertions(+), 1 deletion(-) create mode 100644 drivers/nvdimm/nd_perf.c -- 2.27.0