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/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
#include <aws/io/event_loop.h>
#include <aws/common/clock.h>
#include <aws/common/device_random.h>
#include <aws/common/system_info.h>
#include <aws/common/thread.h>
struct aws_event_loop *aws_event_loop_new_default(struct aws_allocator *alloc, aws_io_clock_fn *clock) {
struct aws_event_loop_options options = {
.thread_options = NULL,
.clock = clock,
};
return aws_event_loop_new_default_with_options(alloc, &options);
}
static void s_event_loop_group_thread_exit(void *user_data) {
struct aws_event_loop_group *el_group = user_data;
aws_simple_completion_callback *completion_callback = el_group->shutdown_options.shutdown_callback_fn;
void *completion_user_data = el_group->shutdown_options.shutdown_callback_user_data;
aws_mem_release(el_group->allocator, el_group);
if (completion_callback != NULL) {
completion_callback(completion_user_data);
}
}
static void s_aws_event_loop_group_shutdown_sync(struct aws_event_loop_group *el_group) {
while (aws_array_list_length(&el_group->event_loops) > 0) {
struct aws_event_loop *loop = NULL;
if (!aws_array_list_back(&el_group->event_loops, &loop)) {
aws_event_loop_destroy(loop);
}
aws_array_list_pop_back(&el_group->event_loops);
}
aws_array_list_clean_up(&el_group->event_loops);
}
static void s_event_loop_destroy_async_thread_fn(void *thread_data) {
struct aws_event_loop_group *el_group = thread_data;
s_aws_event_loop_group_shutdown_sync(el_group);
aws_thread_current_at_exit(s_event_loop_group_thread_exit, el_group);
}
static void s_aws_event_loop_group_shutdown_async(struct aws_event_loop_group *el_group) {
/* It's possible that the last refcount was released on an event-loop thread,
* so we would deadlock if we waited here for all the event-loop threads to shut down.
* Therefore, we spawn a NEW thread and have it wait for all the event-loop threads to shut down
*/
struct aws_thread cleanup_thread;
AWS_ZERO_STRUCT(cleanup_thread);
aws_thread_init(&cleanup_thread, el_group->allocator);
struct aws_thread_options thread_options;
AWS_ZERO_STRUCT(thread_options);
thread_options.cpu_id = -1;
thread_options.join_strategy = AWS_TJS_MANAGED;
aws_thread_launch(&cleanup_thread, s_event_loop_destroy_async_thread_fn, el_group, &thread_options);
}
static struct aws_event_loop_group *s_event_loop_group_new(
struct aws_allocator *alloc,
aws_io_clock_fn *clock,
uint16_t el_count,
uint16_t cpu_group,
bool pin_threads,
aws_new_event_loop_fn *new_loop_fn,
void *new_loop_user_data,
const struct aws_shutdown_callback_options *shutdown_options) {
AWS_ASSERT(new_loop_fn);
size_t group_cpu_count = 0;
struct aws_cpu_info *usable_cpus = NULL;
if (pin_threads) {
group_cpu_count = aws_get_cpu_count_for_group(cpu_group);
if (!group_cpu_count) {
aws_raise_error(AWS_ERROR_INVALID_ARGUMENT);
return NULL;
}
usable_cpus = aws_mem_calloc(alloc, group_cpu_count, sizeof(struct aws_cpu_info));
if (usable_cpus == NULL) {
return NULL;
}
aws_get_cpu_ids_for_group(cpu_group, usable_cpus, group_cpu_count);
}
struct aws_event_loop_group *el_group = aws_mem_calloc(alloc, 1, sizeof(struct aws_event_loop_group));
if (el_group == NULL) {
return NULL;
}
el_group->allocator = alloc;
aws_ref_count_init(
&el_group->ref_count, el_group, (aws_simple_completion_callback *)s_aws_event_loop_group_shutdown_async);
if (aws_array_list_init_dynamic(&el_group->event_loops, alloc, el_count, sizeof(struct aws_event_loop *))) {
goto on_error;
}
for (uint16_t i = 0; i < el_count; ++i) {
/* Don't pin to hyper-threads if a user cared enough to specify a NUMA node */
if (!pin_threads || (i < group_cpu_count && !usable_cpus[i].suspected_hyper_thread)) {
struct aws_thread_options thread_options = *aws_default_thread_options();
struct aws_event_loop_options options = {
.clock = clock,
};
if (pin_threads) {
thread_options.cpu_id = usable_cpus[i].cpu_id;
options.thread_options = &thread_options;
}
struct aws_event_loop *loop = new_loop_fn(alloc, &options, new_loop_user_data);
if (!loop) {
goto on_error;
}
if (aws_array_list_push_back(&el_group->event_loops, (const void *)&loop)) {
aws_event_loop_destroy(loop);
goto on_error;
}
if (aws_event_loop_run(loop)) {
goto on_error;
}
}
}
if (shutdown_options != NULL) {
el_group->shutdown_options = *shutdown_options;
}
if (pin_threads) {
aws_mem_release(alloc, usable_cpus);
}
return el_group;
on_error:
aws_mem_release(alloc, usable_cpus);
s_aws_event_loop_group_shutdown_sync(el_group);
s_event_loop_group_thread_exit(el_group);
return NULL;
}
struct aws_event_loop_group *aws_event_loop_group_new(
struct aws_allocator *alloc,
aws_io_clock_fn *clock,
uint16_t el_count,
aws_new_event_loop_fn *new_loop_fn,
void *new_loop_user_data,
const struct aws_shutdown_callback_options *shutdown_options) {
AWS_ASSERT(new_loop_fn);
AWS_ASSERT(el_count);
return s_event_loop_group_new(alloc, clock, el_count, 0, false, new_loop_fn, new_loop_user_data, shutdown_options);
}
static struct aws_event_loop *s_default_new_event_loop(
struct aws_allocator *allocator,
const struct aws_event_loop_options *options,
void *user_data) {
(void)user_data;
return aws_event_loop_new_default_with_options(allocator, options);
}
struct aws_event_loop_group *aws_event_loop_group_new_default(
struct aws_allocator *alloc,
uint16_t max_threads,
const struct aws_shutdown_callback_options *shutdown_options) {
if (!max_threads) {
uint16_t processor_count = (uint16_t)aws_system_info_processor_count();
/* cut them in half to avoid using hyper threads for the IO work. */
max_threads = processor_count > 1 ? processor_count / 2 : processor_count;
}
return aws_event_loop_group_new(
alloc, aws_high_res_clock_get_ticks, max_threads, s_default_new_event_loop, NULL, shutdown_options);
}
struct aws_event_loop_group *aws_event_loop_group_new_pinned_to_cpu_group(
struct aws_allocator *alloc,
aws_io_clock_fn *clock,
uint16_t el_count,
uint16_t cpu_group,
aws_new_event_loop_fn *new_loop_fn,
void *new_loop_user_data,
const struct aws_shutdown_callback_options *shutdown_options) {
AWS_ASSERT(new_loop_fn);
AWS_ASSERT(el_count);
return s_event_loop_group_new(
alloc, clock, el_count, cpu_group, true, new_loop_fn, new_loop_user_data, shutdown_options);
}
struct aws_event_loop_group *aws_event_loop_group_new_default_pinned_to_cpu_group(
struct aws_allocator *alloc,
uint16_t max_threads,
uint16_t cpu_group,
const struct aws_shutdown_callback_options *shutdown_options) {
if (!max_threads) {
uint16_t processor_count = (uint16_t)aws_system_info_processor_count();
/* cut them in half to avoid using hyper threads for the IO work. */
max_threads = processor_count > 1 ? processor_count / 2 : processor_count;
}
return aws_event_loop_group_new_pinned_to_cpu_group(
alloc, aws_high_res_clock_get_ticks, max_threads, cpu_group, s_default_new_event_loop, NULL, shutdown_options);
}
struct aws_event_loop_group *aws_event_loop_group_acquire(struct aws_event_loop_group *el_group) {
if (el_group != NULL) {
aws_ref_count_acquire(&el_group->ref_count);
}
return el_group;
}
void aws_event_loop_group_release(struct aws_event_loop_group *el_group) {
if (el_group != NULL) {
aws_ref_count_release(&el_group->ref_count);
}
}
size_t aws_event_loop_group_get_loop_count(struct aws_event_loop_group *el_group) {
return aws_array_list_length(&el_group->event_loops);
}
struct aws_event_loop *aws_event_loop_group_get_loop_at(struct aws_event_loop_group *el_group, size_t index) {
struct aws_event_loop *el = NULL;
aws_array_list_get_at(&el_group->event_loops, &el, index);
return el;
}
struct aws_event_loop *aws_event_loop_group_get_next_loop(struct aws_event_loop_group *el_group) {
size_t loop_count = aws_array_list_length(&el_group->event_loops);
AWS_ASSERT(loop_count > 0);
if (loop_count == 0) {
return NULL;
}
/* do one call to get 32 random bits because this hits an actual entropy source and it's not cheap */
uint32_t random_32_bit_num = 0;
aws_device_random_u32(&random_32_bit_num);
/* use the best of two algorithm to select the loop with the lowest load.
* If we find device random is too hard on the kernel, we can seed it and use another random
* number generator. */
/* it's fine and intentional, the case will throw off the top 16 bits and that's what we want. */
uint16_t random_num_a = (uint16_t)random_32_bit_num;
random_num_a = random_num_a % loop_count;
uint16_t random_num_b = (uint16_t)(random_32_bit_num >> 16);
random_num_b = random_num_b % loop_count;
struct aws_event_loop *random_loop_a = NULL;
struct aws_event_loop *random_loop_b = NULL;
aws_array_list_get_at(&el_group->event_loops, &random_loop_a, random_num_a);
aws_array_list_get_at(&el_group->event_loops, &random_loop_b, random_num_b);
/* there's no logical reason why this should ever be possible. It's just best to die if it happens. */
AWS_FATAL_ASSERT((random_loop_a && random_loop_b) && "random_loop_a or random_loop_b is NULL.");
size_t load_a = aws_event_loop_get_load_factor(random_loop_a);
size_t load_b = aws_event_loop_get_load_factor(random_loop_b);
return load_a < load_b ? random_loop_a : random_loop_b;
}
static void s_object_removed(void *value) {
struct aws_event_loop_local_object *object = (struct aws_event_loop_local_object *)value;
if (object->on_object_removed) {
object->on_object_removed(object);
}
}
int aws_event_loop_init_base(struct aws_event_loop *event_loop, struct aws_allocator *alloc, aws_io_clock_fn *clock) {
AWS_ZERO_STRUCT(*event_loop);
event_loop->alloc = alloc;
event_loop->clock = clock;
aws_atomic_init_int(&event_loop->current_load_factor, 0u);
aws_atomic_init_int(&event_loop->next_flush_time, 0u);
if (aws_hash_table_init(&event_loop->local_data, alloc, 20, aws_hash_ptr, aws_ptr_eq, NULL, s_object_removed)) {
return AWS_OP_ERR;
}
return AWS_OP_SUCCESS;
}
void aws_event_loop_clean_up_base(struct aws_event_loop *event_loop) {
aws_hash_table_clean_up(&event_loop->local_data);
}
void aws_event_loop_register_tick_start(struct aws_event_loop *event_loop) {
aws_high_res_clock_get_ticks(&event_loop->latest_tick_start);
}
void aws_event_loop_register_tick_end(struct aws_event_loop *event_loop) {
/* increment the timestamp diff counter (this should always be called from the same thread), the concurrency
* work happens during the flush. */
uint64_t end_tick = 0;
aws_high_res_clock_get_ticks(&end_tick);
size_t elapsed = (size_t)aws_min_u64(end_tick - event_loop->latest_tick_start, SIZE_MAX);
event_loop->current_tick_latency_sum = aws_add_size_saturating(event_loop->current_tick_latency_sum, elapsed);
event_loop->latest_tick_start = 0;
size_t next_flush_time_secs = aws_atomic_load_int(&event_loop->next_flush_time);
/* store as seconds because we can't make a 64-bit integer reliably atomic across platforms. */
uint64_t end_tick_secs = aws_timestamp_convert(end_tick, AWS_TIMESTAMP_NANOS, AWS_TIMESTAMP_SECS, NULL);
/* if a second has passed, flush the load-factor. */
if (end_tick_secs > next_flush_time_secs) {
aws_atomic_store_int(&event_loop->current_load_factor, event_loop->current_tick_latency_sum);
event_loop->current_tick_latency_sum = 0;
/* run again in a second. */
aws_atomic_store_int(&event_loop->next_flush_time, (size_t)(end_tick_secs + 1));
}
}
size_t aws_event_loop_get_load_factor(struct aws_event_loop *event_loop) {
uint64_t current_time = 0;
aws_high_res_clock_get_ticks(¤t_time);
uint64_t current_time_secs = aws_timestamp_convert(current_time, AWS_TIMESTAMP_NANOS, AWS_TIMESTAMP_SECS, NULL);
size_t next_flush_time_secs = aws_atomic_load_int(&event_loop->next_flush_time);
/* safety valve just in case an event-loop had heavy load and then went completely idle. If we haven't
* had an update from the event-loop in 10 seconds, just assume idle. Also, yes this is racy, but it should
* be good enough because an active loop will be updating its counter frequently ( more than once per 10 seconds
* for sure ), in the case where we hit the technical race condition, we don't care anyways and returning 0
* is the desired behavior. */
if (current_time_secs > next_flush_time_secs + 10) {
return 0;
}
return aws_atomic_load_int(&event_loop->current_load_factor);
}
void aws_event_loop_destroy(struct aws_event_loop *event_loop) {
if (!event_loop) {
return;
}
AWS_ASSERT(event_loop->vtable && event_loop->vtable->destroy);
AWS_ASSERT(!aws_event_loop_thread_is_callers_thread(event_loop));
event_loop->vtable->destroy(event_loop);
}
int aws_event_loop_fetch_local_object(
struct aws_event_loop *event_loop,
void *key,
struct aws_event_loop_local_object *obj) {
AWS_ASSERT(aws_event_loop_thread_is_callers_thread(event_loop));
struct aws_hash_element *object = NULL;
if (!aws_hash_table_find(&event_loop->local_data, key, &object) && object) {
*obj = *(struct aws_event_loop_local_object *)object->value;
return AWS_OP_SUCCESS;
}
return AWS_OP_ERR;
}
int aws_event_loop_put_local_object(struct aws_event_loop *event_loop, struct aws_event_loop_local_object *obj) {
AWS_ASSERT(aws_event_loop_thread_is_callers_thread(event_loop));
struct aws_hash_element *object = NULL;
int was_created = 0;
if (!aws_hash_table_create(&event_loop->local_data, obj->key, &object, &was_created)) {
object->key = obj->key;
object->value = obj;
return AWS_OP_SUCCESS;
}
return AWS_OP_ERR;
}
int aws_event_loop_remove_local_object(
struct aws_event_loop *event_loop,
void *key,
struct aws_event_loop_local_object *removed_obj) {
AWS_ASSERT(aws_event_loop_thread_is_callers_thread(event_loop));
struct aws_hash_element existing_object;
AWS_ZERO_STRUCT(existing_object);
int was_present = 0;
struct aws_hash_element *remove_candidate = removed_obj ? &existing_object : NULL;
if (!aws_hash_table_remove(&event_loop->local_data, key, remove_candidate, &was_present)) {
if (remove_candidate && was_present) {
*removed_obj = *(struct aws_event_loop_local_object *)existing_object.value;
}
return AWS_OP_SUCCESS;
}
return AWS_OP_ERR;
}
int aws_event_loop_run(struct aws_event_loop *event_loop) {
AWS_ASSERT(event_loop->vtable && event_loop->vtable->run);
return event_loop->vtable->run(event_loop);
}
int aws_event_loop_stop(struct aws_event_loop *event_loop) {
AWS_ASSERT(event_loop->vtable && event_loop->vtable->stop);
return event_loop->vtable->stop(event_loop);
}
int aws_event_loop_wait_for_stop_completion(struct aws_event_loop *event_loop) {
AWS_ASSERT(!aws_event_loop_thread_is_callers_thread(event_loop));
AWS_ASSERT(event_loop->vtable && event_loop->vtable->wait_for_stop_completion);
return event_loop->vtable->wait_for_stop_completion(event_loop);
}
void aws_event_loop_schedule_task_now(struct aws_event_loop *event_loop, struct aws_task *task) {
AWS_ASSERT(event_loop->vtable && event_loop->vtable->schedule_task_now);
AWS_ASSERT(task);
event_loop->vtable->schedule_task_now(event_loop, task);
}
void aws_event_loop_schedule_task_future(
struct aws_event_loop *event_loop,
struct aws_task *task,
uint64_t run_at_nanos) {
AWS_ASSERT(event_loop->vtable && event_loop->vtable->schedule_task_future);
AWS_ASSERT(task);
event_loop->vtable->schedule_task_future(event_loop, task, run_at_nanos);
}
void aws_event_loop_cancel_task(struct aws_event_loop *event_loop, struct aws_task *task) {
AWS_ASSERT(event_loop->vtable && event_loop->vtable->cancel_task);
AWS_ASSERT(aws_event_loop_thread_is_callers_thread(event_loop));
AWS_ASSERT(task);
event_loop->vtable->cancel_task(event_loop, task);
}
#if AWS_USE_IO_COMPLETION_PORTS
int aws_event_loop_connect_handle_to_io_completion_port(
struct aws_event_loop *event_loop,
struct aws_io_handle *handle) {
AWS_ASSERT(event_loop->vtable && event_loop->vtable->connect_to_io_completion_port);
return event_loop->vtable->connect_to_io_completion_port(event_loop, handle);
}
#else /* !AWS_USE_IO_COMPLETION_PORTS */
int aws_event_loop_subscribe_to_io_events(
struct aws_event_loop *event_loop,
struct aws_io_handle *handle,
int events,
aws_event_loop_on_event_fn *on_event,
void *user_data) {
AWS_ASSERT(event_loop->vtable && event_loop->vtable->subscribe_to_io_events);
return event_loop->vtable->subscribe_to_io_events(event_loop, handle, events, on_event, user_data);
}
#endif /* AWS_USE_IO_COMPLETION_PORTS */
int aws_event_loop_unsubscribe_from_io_events(struct aws_event_loop *event_loop, struct aws_io_handle *handle) {
AWS_ASSERT(aws_event_loop_thread_is_callers_thread(event_loop));
AWS_ASSERT(event_loop->vtable && event_loop->vtable->unsubscribe_from_io_events);
return event_loop->vtable->unsubscribe_from_io_events(event_loop, handle);
}
void aws_event_loop_free_io_event_resources(struct aws_event_loop *event_loop, struct aws_io_handle *handle) {
AWS_ASSERT(event_loop && event_loop->vtable->free_io_event_resources);
event_loop->vtable->free_io_event_resources(handle->additional_data);
}
bool aws_event_loop_thread_is_callers_thread(struct aws_event_loop *event_loop) {
AWS_ASSERT(event_loop->vtable && event_loop->vtable->is_on_callers_thread);
return event_loop->vtable->is_on_callers_thread(event_loop);
}
int aws_event_loop_current_clock_time(struct aws_event_loop *event_loop, uint64_t *time_nanos) {
AWS_ASSERT(event_loop->clock);
return event_loop->clock(time_nanos);
}
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