+++ /dev/null
-/*
- * (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 "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)) {
- 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));
-}
-
-static
-void overflow_callback(struct perf_event *event, int nmi,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
-}
-
-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 = perf_event_create_kernel_counter(attr,
- cpu, NULL, overflow_callback);
- if (!pevent || IS_ERR(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] = perf_event_create_kernel_counter(attr,
- cpu, NULL, overflow_callback);
- if (!events[cpu] || IS_ERR(events[cpu])) {
- ret = -EINVAL;
- goto counter_error;
- }
- }
- 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(unsigned long) * CHAR_BIT;
- field->event_field.type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
- field->event_field.type.u.basic.integer.signedness = is_signed_type(unsigned long);
- 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_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");
projects / lttng-modules.git / blobdiff