Messages in this thread Patch in this message | | | From | Kajol Jain <> | Subject | [RFC 1/4] drivers/nvdimm: Add perf interface to expose nvdimm performance stats | Date | Wed, 12 May 2021 22:08:21 +0530 |
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Patch adds performance stats reporting support for nvdimm. Added interface includes support for a pmu register function and callbacks to be used by the arch/platform specific drivers. User could use the standard perf tool to access perf events exposed via pmu.
A structure is added called nvdimm_pmu which can be used to add platform specific data like supported events and callbacks to pmu functions like event_init/add/delete/read. It also adds unregister_nvdimm_pmu function to handle unregistering of a pmu device.
Signed-off-by: Kajol Jain <kjain@linux.ibm.com> --- drivers/nvdimm/Makefile | 1 + drivers/nvdimm/nd_perf.c | 111 +++++++++++++++++++++++++++++++++++++++ include/linux/nd.h | 31 +++++++++++ 3 files changed, 143 insertions(+) create mode 100644 drivers/nvdimm/nd_perf.c
diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile index 29203f3d3069..25dba6095612 100644 --- a/drivers/nvdimm/Makefile +++ b/drivers/nvdimm/Makefile @@ -18,6 +18,7 @@ nd_e820-y := e820.o libnvdimm-y := core.o libnvdimm-y += bus.o libnvdimm-y += dimm_devs.o +libnvdimm-y += nd_perf.o libnvdimm-y += dimm.o libnvdimm-y += region_devs.o libnvdimm-y += region.o diff --git a/drivers/nvdimm/nd_perf.c b/drivers/nvdimm/nd_perf.c new file mode 100644 index 000000000000..d28bec2b61a2 --- /dev/null +++ b/drivers/nvdimm/nd_perf.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * nd_perf.c: NVDIMM Device Performance Monitoring Unit support + * + * Perf interface to expose nvdimm performance stats. + * + * Copyright (C) 2021 IBM Corporation + */ + +#define pr_fmt(fmt) "nvdimm_pmu: " fmt + +#include <linux/nd.h> + +#define to_nvdimm_pmu(_pmu) container_of(_pmu, struct nvdimm_pmu, pmu) + +static int nvdimm_pmu_event_init(struct perf_event *event) +{ + struct nvdimm_pmu *nd_pmu = to_nvdimm_pmu(event->pmu); + + /* test the event attr type for PMU enumeration */ + if (event->attr.type != event->pmu->type) + return -ENOENT; + + /* it does not support event sampling mode */ + if (is_sampling_event(event)) + return -EINVAL; + + /* no branch sampling */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + + /* jump to arch/platform specific callbacks if any */ + if (nd_pmu && nd_pmu->event_init) + return nd_pmu->event_init(event, nd_pmu->dev); + + return 0; +} + +static void nvdimm_pmu_read(struct perf_event *event) +{ + struct nvdimm_pmu *nd_pmu = to_nvdimm_pmu(event->pmu); + + /* jump to arch/platform specific callbacks if any */ + if (nd_pmu && nd_pmu->read) + nd_pmu->read(event, nd_pmu->dev); +} + +static void nvdimm_pmu_del(struct perf_event *event, int flags) +{ + struct nvdimm_pmu *nd_pmu = to_nvdimm_pmu(event->pmu); + + /* jump to arch/platform specific callbacks if any */ + if (nd_pmu && nd_pmu->del) + nd_pmu->del(event, flags, nd_pmu->dev); +} + +static int nvdimm_pmu_add(struct perf_event *event, int flags) +{ + struct nvdimm_pmu *nd_pmu = to_nvdimm_pmu(event->pmu); + + if (flags & PERF_EF_START) + /* jump to arch/platform specific callbacks if any */ + if (nd_pmu && nd_pmu->add) + return nd_pmu->add(event, flags, nd_pmu->dev); + return 0; +} + +int register_nvdimm_pmu(struct nvdimm_pmu *nd_pmu, struct platform_device *pdev) +{ + int rc; + + if (!nd_pmu || !pdev) + return -EINVAL; + + nd_pmu->pmu.task_ctx_nr = perf_invalid_context; + nd_pmu->pmu.event_init = nvdimm_pmu_event_init; + nd_pmu->pmu.add = nvdimm_pmu_add; + nd_pmu->pmu.del = nvdimm_pmu_del; + nd_pmu->pmu.read = nvdimm_pmu_read; + nd_pmu->pmu.name = nd_pmu->name; + nd_pmu->pmu.attr_groups = nd_pmu->attr_groups; + nd_pmu->pmu.capabilities = PERF_PMU_CAP_NO_INTERRUPT | + PERF_PMU_CAP_NO_EXCLUDE; + + /* + * Adding platform_device->dev pointer to nvdimm_pmu, so that we can + * access that device data in PMU callbacks and also pass it to + * arch/platform specific code. + */ + nd_pmu->dev = &pdev->dev; + + rc = perf_pmu_register(&nd_pmu->pmu, nd_pmu->name, -1); + if (rc) + return rc; + + pr_info("%s NVDIMM performance monitor support registered\n", + nd_pmu->name); + + return 0; +} +EXPORT_SYMBOL_GPL(register_nvdimm_pmu); + +void unregister_nvdimm_pmu(struct pmu *nd_pmu) +{ + /* + * nd_pmu will get free in arch/platform specific code once + * corresponding pmu get unregistered. + */ + perf_pmu_unregister(nd_pmu); +} +EXPORT_SYMBOL_GPL(unregister_nvdimm_pmu); diff --git a/include/linux/nd.h b/include/linux/nd.h index ee9ad76afbba..fa6e60b2b368 100644 --- a/include/linux/nd.h +++ b/include/linux/nd.h @@ -8,6 +8,8 @@ #include <linux/ndctl.h> #include <linux/device.h> #include <linux/badblocks.h> +#include <linux/platform_device.h> +#include <linux/perf_event.h> enum nvdimm_event { NVDIMM_REVALIDATE_POISON, @@ -23,6 +25,35 @@ enum nvdimm_claim_class { NVDIMM_CCLASS_UNKNOWN, }; +/** + * struct nvdimm_pmu - data structure for nvdimm perf driver + * + * @name: name of the nvdimm pmu device. + * @pmu: pmu data structure for nvdimm performance stats. + * @cpu: designated cpu for counter access. + * @dev: nvdimm device pointer. + * @functions(event_init/add/del/read): platform specific callbacks. + * @attr_groups: data structure for events/formats/cpumask. + * @node: node for cpu hotplug notifier link. + * @cpuhp_state: state for cpu hotplug notification. + */ +struct nvdimm_pmu { + const char *name; + struct pmu pmu; + int cpu; + struct device *dev; + int (*event_init)(struct perf_event *event, struct device *dev); + int (*add)(struct perf_event *event, int flags, struct device *dev); + void (*del)(struct perf_event *event, int flags, struct device *dev); + void (*read)(struct perf_event *event, struct device *dev); + const struct attribute_group **attr_groups; + struct hlist_node node; + enum cpuhp_state cpuhp_state; +}; + +int register_nvdimm_pmu(struct nvdimm_pmu *nvdimm, struct platform_device *pdev); +void unregister_nvdimm_pmu(struct pmu *pmu); + struct nd_device_driver { struct device_driver drv; unsigned long type; -- 2.27.0
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