X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lttng-context-perf-counters.c;h=467b71801a6529a14e2850a0d57148a89b0b26a1;hb=refs%2Fheads%2Fstable-2.7;hp=e9a57888c4db8b1d818e76c17c1e10d9421809c4;hpb=c24a0d710f6aac1484bd02bb6375e8de7429edd0;p=lttng-modules.git diff --git a/lttng-context-perf-counters.c b/lttng-context-perf-counters.c index e9a57888..467b7180 100644 --- a/lttng-context-perf-counters.c +++ b/lttng-context-perf-counters.c @@ -1,10 +1,23 @@ /* - * (C) Copyright 2009-2011 - - * Mathieu Desnoyers + * lttng-context-perf-counters.c * * LTTng performance monitoring counters (perf-counters) integration module. * - * Dual LGPL v2.1/GPL v2 license. + * Copyright (C) 2009-2012 Mathieu Desnoyers + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; only + * version 2.1 of the License. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include @@ -12,24 +25,19 @@ #include #include #include -#include "ltt-events.h" +#include +#include "lttng-events.h" #include "wrapper/ringbuffer/frontend_types.h" #include "wrapper/vmalloc.h" -#include "ltt-tracer.h" - -/* - * TODO: Add CPU hotplug support. - */ - -static DEFINE_MUTEX(perf_counter_mutex); -static LIST_HEAD(perf_counter_contexts); +#include "wrapper/perf.h" +#include "lttng-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 += lib_ring_buffer_align(offset, lttng_alignof(uint64_t)); size += sizeof(uint64_t); return size; } @@ -37,47 +45,132 @@ size_t perf_counter_get_size(size_t offset) static void perf_counter_record(struct lttng_ctx_field *field, struct lib_ring_buffer_ctx *ctx, - struct ltt_channel *chan) + struct lttng_channel *chan) { struct perf_event *event; uint64_t value; - event = field->u.perf_counter.e[ctx->cpu]; - event->pmu->read(event); - value = local64_read(&event->count); - lib_ring_buffer_align_ctx(ctx, ltt_alignof(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, lttng_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; + struct perf_event **events = field->u.perf_counter->e; int cpu; - mutex_lock(&perf_counter_mutex); - list_del(&field->u.perf_counter.head); + get_online_cpus(); for_each_online_cpu(cpu) perf_event_release_kernel(events[cpu]); - mutex_unlock(&perf_counter_mutex); + 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(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 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; @@ -88,7 +181,7 @@ int lttng_add_perf_counter_to_ctx(uint32_t type, if (!events) return -ENOMEM; - attr = kzalloc(sizeof(*field->u.perf_counter.attr), GFP_KERNEL); + attr = kzalloc(sizeof(struct perf_event_attr), GFP_KERNEL); if (!attr) { ret = -ENOMEM; goto error_attr; @@ -100,61 +193,90 @@ int lttng_add_perf_counter_to_ctx(uint32_t type, attr->pinned = 1; attr->disabled = 0; - mutex_lock(&perf_counter_mutex); - - for_each_online_cpu(cpu) { - events[cpu] = perf_event_create_kernel_counter(attr, - cpu, NULL, overflow_callback); - if (!events[cpu]) { - ret = -EINVAL; - goto error; - } + 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 (!field->event_field.name) + if (!name_alloc) { + ret = -ENOMEM; goto name_alloc_error; + } field = lttng_append_context(ctx); if (!field) { ret = -ENOMEM; - goto error; + 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(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.size = sizeof(uint64_t) * CHAR_BIT; + field->event_field.type.u.basic.integer.alignment = lttng_alignof(uint64_t) * CHAR_BIT; + field->event_field.type.u.basic.integer.signedness = lttng_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.e = events; - field->u.perf_counter.attr = attr; - - list_add(&field->u.perf_counter.head, &perf_counter_contexts); - mutex_unlock(&perf_counter_mutex); + field->u.perf_counter = perf_field; + perf_field->hp_enable = 1; + lttng_context_update(*ctx); wrapper_vmalloc_sync_all(); return 0; -error: - kfree(name_alloc); -name_alloc_error: +counter_busy: +counter_error: for_each_online_cpu(cpu) { - if (events[cpu]) + if (events[cpu] && !IS_ERR(events[cpu])) perf_event_release_kernel(events[cpu]); } - mutex_unlock(&perf_counter_mutex); + 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");