| 1 | /* |
| 2 | * (C) Copyright 2009-2011 - |
| 3 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 4 | * |
| 5 | * LTTng performance monitoring counters (perf-counters) integration module. |
| 6 | * |
| 7 | * Dual LGPL v2.1/GPL v2 license. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/slab.h> |
| 12 | #include <linux/perf_event.h> |
| 13 | #include <linux/list.h> |
| 14 | #include <linux/string.h> |
| 15 | #include "ltt-events.h" |
| 16 | #include "wrapper/ringbuffer/frontend_types.h" |
| 17 | #include "wrapper/vmalloc.h" |
| 18 | #include "ltt-tracer.h" |
| 19 | |
| 20 | /* |
| 21 | * TODO: Add CPU hotplug support. |
| 22 | */ |
| 23 | |
| 24 | static DEFINE_MUTEX(perf_counter_mutex); |
| 25 | static LIST_HEAD(perf_counter_contexts); |
| 26 | |
| 27 | static |
| 28 | size_t perf_counter_get_size(size_t offset) |
| 29 | { |
| 30 | size_t size = 0; |
| 31 | |
| 32 | size += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); |
| 33 | size += sizeof(uint64_t); |
| 34 | return size; |
| 35 | } |
| 36 | |
| 37 | static |
| 38 | void perf_counter_record(struct lttng_ctx_field *field, |
| 39 | struct lib_ring_buffer_ctx *ctx, |
| 40 | struct ltt_channel *chan) |
| 41 | { |
| 42 | struct perf_event *event; |
| 43 | uint64_t value; |
| 44 | |
| 45 | event = field->u.perf_counter.e[ctx->cpu]; |
| 46 | event->pmu->read(event); |
| 47 | value = local64_read(&event->count); |
| 48 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(value)); |
| 49 | chan->ops->event_write(ctx, &value, sizeof(value)); |
| 50 | } |
| 51 | |
| 52 | static |
| 53 | void overflow_callback(struct perf_event *event, int nmi, |
| 54 | struct perf_sample_data *data, |
| 55 | struct pt_regs *regs) |
| 56 | { |
| 57 | } |
| 58 | |
| 59 | static |
| 60 | void lttng_destroy_perf_counter_field(struct lttng_ctx_field *field) |
| 61 | { |
| 62 | struct perf_event **events = field->u.perf_counter.e; |
| 63 | int cpu; |
| 64 | |
| 65 | mutex_lock(&perf_counter_mutex); |
| 66 | list_del(&field->u.perf_counter.head); |
| 67 | for_each_online_cpu(cpu) |
| 68 | perf_event_release_kernel(events[cpu]); |
| 69 | mutex_unlock(&perf_counter_mutex); |
| 70 | kfree(field->event_field.name); |
| 71 | kfree(field->u.perf_counter.attr); |
| 72 | kfree(events); |
| 73 | } |
| 74 | |
| 75 | int lttng_add_perf_counter_to_ctx(uint32_t type, |
| 76 | uint64_t config, |
| 77 | const char *name, |
| 78 | struct lttng_ctx **ctx) |
| 79 | { |
| 80 | struct lttng_ctx_field *field; |
| 81 | struct perf_event **events; |
| 82 | struct perf_event_attr *attr; |
| 83 | int ret; |
| 84 | int cpu; |
| 85 | char *name_alloc; |
| 86 | |
| 87 | events = kzalloc(num_possible_cpus() * sizeof(*events), GFP_KERNEL); |
| 88 | if (!events) |
| 89 | return -ENOMEM; |
| 90 | |
| 91 | attr = kzalloc(sizeof(*field->u.perf_counter.attr), GFP_KERNEL); |
| 92 | if (!attr) { |
| 93 | ret = -ENOMEM; |
| 94 | goto error_attr; |
| 95 | } |
| 96 | |
| 97 | attr->type = type; |
| 98 | attr->config = config; |
| 99 | attr->size = sizeof(struct perf_event_attr); |
| 100 | attr->pinned = 1; |
| 101 | attr->disabled = 0; |
| 102 | |
| 103 | mutex_lock(&perf_counter_mutex); |
| 104 | |
| 105 | for_each_online_cpu(cpu) { |
| 106 | events[cpu] = perf_event_create_kernel_counter(attr, |
| 107 | cpu, NULL, overflow_callback); |
| 108 | if (!events[cpu]) { |
| 109 | ret = -EINVAL; |
| 110 | goto error; |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | name_alloc = kstrdup(name, GFP_KERNEL); |
| 115 | if (!field->event_field.name) |
| 116 | goto name_alloc_error; |
| 117 | |
| 118 | field = lttng_append_context(ctx); |
| 119 | if (!field) { |
| 120 | ret = -ENOMEM; |
| 121 | goto error; |
| 122 | } |
| 123 | field->destroy = lttng_destroy_perf_counter_field; |
| 124 | |
| 125 | field->event_field.name = name_alloc; |
| 126 | field->event_field.type.atype = atype_integer; |
| 127 | field->event_field.type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT; |
| 128 | field->event_field.type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT; |
| 129 | field->event_field.type.u.basic.integer.signedness = is_signed_type(unsigned long); |
| 130 | field->event_field.type.u.basic.integer.reverse_byte_order = 0; |
| 131 | field->event_field.type.u.basic.integer.base = 10; |
| 132 | field->event_field.type.u.basic.integer.encoding = lttng_encode_none; |
| 133 | field->get_size = perf_counter_get_size; |
| 134 | field->record = perf_counter_record; |
| 135 | field->u.perf_counter.e = events; |
| 136 | field->u.perf_counter.attr = attr; |
| 137 | |
| 138 | list_add(&field->u.perf_counter.head, &perf_counter_contexts); |
| 139 | mutex_unlock(&perf_counter_mutex); |
| 140 | |
| 141 | wrapper_vmalloc_sync_all(); |
| 142 | return 0; |
| 143 | |
| 144 | error: |
| 145 | kfree(name_alloc); |
| 146 | name_alloc_error: |
| 147 | for_each_online_cpu(cpu) { |
| 148 | if (events[cpu]) |
| 149 | perf_event_release_kernel(events[cpu]); |
| 150 | } |
| 151 | mutex_unlock(&perf_counter_mutex); |
| 152 | kfree(attr); |
| 153 | error_attr: |
| 154 | kfree(events); |
| 155 | return ret; |
| 156 | } |
| 157 | |
| 158 | MODULE_LICENSE("GPL and additional rights"); |
| 159 | MODULE_AUTHOR("Mathieu Desnoyers"); |
| 160 | MODULE_DESCRIPTION("Linux Trace Toolkit Perf Support"); |