| /* |
| * (C) Copyright 2009-2011 - |
| * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| * |
| * LTTng performance monitoring counters (perf-counters) integration module. |
| * |
| * Dual LGPL v2.1/GPL v2 license. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/perf_event.h> |
| #include <linux/list.h> |
| #include <linux/string.h> |
| #include "ltt-events.h" |
| #include "wrapper/ringbuffer/frontend_types.h" |
| #include "wrapper/vmalloc.h" |
| #include "wrapper/perf.h" |
| #include "ltt-tracer.h" |
| |
| static |
| size_t perf_counter_get_size(size_t offset) |
| { |
| size_t size = 0; |
| |
| size += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); |
| size += sizeof(uint64_t); |
| return size; |
| } |
| |
| static |
| void perf_counter_record(struct lttng_ctx_field *field, |
| struct lib_ring_buffer_ctx *ctx, |
| struct ltt_channel *chan) |
| { |
| struct perf_event *event; |
| uint64_t value; |
| |
| event = field->u.perf_counter->e[ctx->cpu]; |
| if (likely(event)) { |
| if (unlikely(event->state == PERF_EVENT_STATE_ERROR)) { |
| value = 0; |
| } else { |
| event->pmu->read(event); |
| value = local64_read(&event->count); |
| } |
| } else { |
| /* |
| * Perf chooses not to be clever and not to support enabling a |
| * perf counter before the cpu is brought up. Therefore, we need |
| * to support having events coming (e.g. scheduler events) |
| * before the counter is setup. Write an arbitrary 0 in this |
| * case. |
| */ |
| value = 0; |
| } |
| lib_ring_buffer_align_ctx(ctx, ltt_alignof(value)); |
| chan->ops->event_write(ctx, &value, sizeof(value)); |
| } |
| |
| #if defined(CONFIG_PERF_EVENTS) && (LINUX_VERSION_CODE >= KERNEL_VERSION(3,0,99)) |
| static |
| void overflow_callback(struct perf_event *event, |
| struct perf_sample_data *data, |
| struct pt_regs *regs) |
| { |
| } |
| #else |
| static |
| void overflow_callback(struct perf_event *event, int nmi, |
| struct perf_sample_data *data, |
| struct pt_regs *regs) |
| { |
| } |
| #endif |
| |
| static |
| void lttng_destroy_perf_counter_field(struct lttng_ctx_field *field) |
| { |
| struct perf_event **events = field->u.perf_counter->e; |
| int cpu; |
| |
| get_online_cpus(); |
| for_each_online_cpu(cpu) |
| perf_event_release_kernel(events[cpu]); |
| put_online_cpus(); |
| #ifdef CONFIG_HOTPLUG_CPU |
| unregister_cpu_notifier(&field->u.perf_counter->nb); |
| #endif |
| kfree(field->event_field.name); |
| kfree(field->u.perf_counter->attr); |
| kfree(events); |
| kfree(field->u.perf_counter); |
| } |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| |
| /** |
| * lttng_perf_counter_hp_callback - CPU hotplug callback |
| * @nb: notifier block |
| * @action: hotplug action to take |
| * @hcpu: CPU number |
| * |
| * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) |
| * |
| * We can setup perf counters when the cpu is online (up prepare seems to be too |
| * soon). |
| */ |
| static |
| int __cpuinit lttng_perf_counter_cpu_hp_callback(struct notifier_block *nb, |
| unsigned long action, |
| void *hcpu) |
| { |
| unsigned int cpu = (unsigned long) hcpu; |
| struct lttng_perf_counter_field *perf_field = |
| container_of(nb, struct lttng_perf_counter_field, nb); |
| struct perf_event **events = perf_field->e; |
| struct perf_event_attr *attr = perf_field->attr; |
| struct perf_event *pevent; |
| |
| if (!perf_field->hp_enable) |
| return NOTIFY_OK; |
| |
| switch (action) { |
| case CPU_ONLINE: |
| case CPU_ONLINE_FROZEN: |
| pevent = wrapper_perf_event_create_kernel_counter(attr, |
| cpu, NULL, overflow_callback); |
| if (!pevent || IS_ERR(pevent)) |
| return NOTIFY_BAD; |
| if (pevent->state == PERF_EVENT_STATE_ERROR) { |
| perf_event_release_kernel(pevent); |
| return NOTIFY_BAD; |
| } |
| barrier(); /* Create perf counter before setting event */ |
| events[cpu] = pevent; |
| break; |
| case CPU_UP_CANCELED: |
| case CPU_UP_CANCELED_FROZEN: |
| case CPU_DEAD: |
| case CPU_DEAD_FROZEN: |
| pevent = events[cpu]; |
| events[cpu] = NULL; |
| barrier(); /* NULLify event before perf counter teardown */ |
| perf_event_release_kernel(pevent); |
| break; |
| } |
| return NOTIFY_OK; |
| } |
| |
| #endif |
| |
| int lttng_add_perf_counter_to_ctx(uint32_t type, |
| uint64_t config, |
| const char *name, |
| struct lttng_ctx **ctx) |
| { |
| struct lttng_ctx_field *field; |
| struct lttng_perf_counter_field *perf_field; |
| struct perf_event **events; |
| struct perf_event_attr *attr; |
| int ret; |
| int cpu; |
| char *name_alloc; |
| |
| events = kzalloc(num_possible_cpus() * sizeof(*events), GFP_KERNEL); |
| if (!events) |
| return -ENOMEM; |
| |
| attr = kzalloc(sizeof(struct perf_event_attr), GFP_KERNEL); |
| if (!attr) { |
| ret = -ENOMEM; |
| goto error_attr; |
| } |
| |
| attr->type = type; |
| attr->config = config; |
| attr->size = sizeof(struct perf_event_attr); |
| attr->pinned = 1; |
| attr->disabled = 0; |
| |
| perf_field = kzalloc(sizeof(struct lttng_perf_counter_field), GFP_KERNEL); |
| if (!perf_field) { |
| ret = -ENOMEM; |
| goto error_alloc_perf_field; |
| } |
| perf_field->e = events; |
| perf_field->attr = attr; |
| |
| name_alloc = kstrdup(name, GFP_KERNEL); |
| if (!name_alloc) { |
| ret = -ENOMEM; |
| goto name_alloc_error; |
| } |
| |
| field = lttng_append_context(ctx); |
| if (!field) { |
| ret = -ENOMEM; |
| goto append_context_error; |
| } |
| if (lttng_find_context(*ctx, name_alloc)) { |
| ret = -EEXIST; |
| goto find_error; |
| } |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| perf_field->nb.notifier_call = |
| lttng_perf_counter_cpu_hp_callback; |
| perf_field->nb.priority = 0; |
| register_cpu_notifier(&perf_field->nb); |
| #endif |
| |
| get_online_cpus(); |
| for_each_online_cpu(cpu) { |
| events[cpu] = wrapper_perf_event_create_kernel_counter(attr, |
| cpu, NULL, overflow_callback); |
| if (!events[cpu] || IS_ERR(events[cpu])) { |
| ret = -EINVAL; |
| goto counter_error; |
| } |
| if (events[cpu]->state == PERF_EVENT_STATE_ERROR) { |
| ret = -EBUSY; |
| goto counter_busy; |
| } |
| } |
| put_online_cpus(); |
| |
| field->destroy = lttng_destroy_perf_counter_field; |
| |
| field->event_field.name = name_alloc; |
| field->event_field.type.atype = atype_integer; |
| field->event_field.type.u.basic.integer.size = sizeof(uint64_t) * CHAR_BIT; |
| field->event_field.type.u.basic.integer.alignment = ltt_alignof(uint64_t) * CHAR_BIT; |
| field->event_field.type.u.basic.integer.signedness = is_signed_type(uint64_t); |
| field->event_field.type.u.basic.integer.reverse_byte_order = 0; |
| field->event_field.type.u.basic.integer.base = 10; |
| field->event_field.type.u.basic.integer.encoding = lttng_encode_none; |
| field->get_size = perf_counter_get_size; |
| field->record = perf_counter_record; |
| field->u.perf_counter = perf_field; |
| perf_field->hp_enable = 1; |
| |
| wrapper_vmalloc_sync_all(); |
| return 0; |
| |
| counter_busy: |
| counter_error: |
| for_each_online_cpu(cpu) { |
| if (events[cpu] && !IS_ERR(events[cpu])) |
| perf_event_release_kernel(events[cpu]); |
| } |
| put_online_cpus(); |
| #ifdef CONFIG_HOTPLUG_CPU |
| unregister_cpu_notifier(&perf_field->nb); |
| #endif |
| find_error: |
| lttng_remove_context_field(ctx, field); |
| append_context_error: |
| kfree(name_alloc); |
| name_alloc_error: |
| kfree(perf_field); |
| error_alloc_perf_field: |
| kfree(attr); |
| error_attr: |
| kfree(events); |
| return ret; |
| } |
| |
| MODULE_LICENSE("GPL and additional rights"); |
| MODULE_AUTHOR("Mathieu Desnoyers"); |
| MODULE_DESCRIPTION("Linux Trace Toolkit Perf Support"); |