Mercurial > hg > nginx
view src/event/modules/ngx_win32_poll_module.c @ 9138:a90f79792b5d
QUIC: optimized ACK delay.
Previously ACK was not generated if max_ack_delay was not yet expired and the
number of unacknowledged ack-eliciting packets was less than two, as allowed by
RFC 9000 13.2.1-13.2.2. However this only makes sense to avoid sending ACK-only
packets, as explained by the RFC:
On the other hand, reducing the frequency of packets that carry only
acknowledgments reduces packet transmission and processing cost at both
endpoints.
Now ACK is delayed only if output frame queue is empty. Otherwise ACK is sent
immediately, which significantly improves QUIC performance with certain tests.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Thu, 27 Jul 2023 16:37:17 +0400 |
parents | efd71d49bde0 |
children |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Maxim Dounin * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> static ngx_int_t ngx_poll_init(ngx_cycle_t *cycle, ngx_msec_t timer); static void ngx_poll_done(ngx_cycle_t *cycle); static ngx_int_t ngx_poll_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags); static ngx_int_t ngx_poll_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags); static ngx_int_t ngx_poll_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags); static char *ngx_poll_init_conf(ngx_cycle_t *cycle, void *conf); static struct pollfd *event_list; static ngx_connection_t **event_index; static ngx_uint_t nevents; static ngx_str_t poll_name = ngx_string("poll"); static ngx_event_module_t ngx_poll_module_ctx = { &poll_name, NULL, /* create configuration */ ngx_poll_init_conf, /* init configuration */ { ngx_poll_add_event, /* add an event */ ngx_poll_del_event, /* delete an event */ ngx_poll_add_event, /* enable an event */ ngx_poll_del_event, /* disable an event */ NULL, /* add an connection */ NULL, /* delete an connection */ NULL, /* trigger a notify */ ngx_poll_process_events, /* process the events */ ngx_poll_init, /* init the events */ ngx_poll_done /* done the events */ } }; ngx_module_t ngx_poll_module = { NGX_MODULE_V1, &ngx_poll_module_ctx, /* module context */ NULL, /* module directives */ NGX_EVENT_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_int_t ngx_poll_init(ngx_cycle_t *cycle, ngx_msec_t timer) { struct pollfd *list; ngx_connection_t **index; if (event_list == NULL) { nevents = 0; } if (ngx_process >= NGX_PROCESS_WORKER || cycle->old_cycle == NULL || cycle->old_cycle->connection_n < cycle->connection_n) { list = ngx_alloc(sizeof(struct pollfd) * cycle->connection_n, cycle->log); if (list == NULL) { return NGX_ERROR; } if (event_list) { ngx_memcpy(list, event_list, sizeof(struct pollfd) * nevents); ngx_free(event_list); } event_list = list; index = ngx_alloc(sizeof(ngx_connection_t *) * cycle->connection_n, cycle->log); if (index == NULL) { return NGX_ERROR; } if (event_index) { ngx_memcpy(index, event_index, sizeof(ngx_connection_t *) * nevents); ngx_free(event_index); } event_index = index; } ngx_io = ngx_os_io; ngx_event_actions = ngx_poll_module_ctx.actions; ngx_event_flags = NGX_USE_LEVEL_EVENT; return NGX_OK; } static void ngx_poll_done(ngx_cycle_t *cycle) { ngx_free(event_list); ngx_free(event_index); event_list = NULL; event_index = NULL; } static ngx_int_t ngx_poll_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags) { ngx_event_t *e; ngx_connection_t *c; c = ev->data; ev->active = 1; if (ev->index != NGX_INVALID_INDEX) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "poll event fd:%d ev:%i is already set", c->fd, event); return NGX_OK; } if (event == NGX_READ_EVENT) { e = c->write; #if (NGX_READ_EVENT != POLLIN) event = POLLIN; #endif } else { e = c->read; #if (NGX_WRITE_EVENT != POLLOUT) event = POLLOUT; #endif } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "poll add event: fd:%d ev:%i", c->fd, event); if (e == NULL || e->index == NGX_INVALID_INDEX) { event_list[nevents].fd = c->fd; event_list[nevents].events = (short) event; event_list[nevents].revents = 0; event_index[nevents] = c; ev->index = nevents; nevents++; } else { ngx_log_debug1(NGX_LOG_DEBUG_EVENT, ev->log, 0, "poll add index: %i", e->index); event_list[e->index].events |= (short) event; ev->index = e->index; } return NGX_OK; } static ngx_int_t ngx_poll_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags) { ngx_event_t *e; ngx_connection_t *c; c = ev->data; ev->active = 0; if (ev->index == NGX_INVALID_INDEX) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "poll event fd:%d ev:%i is already deleted", c->fd, event); return NGX_OK; } if (event == NGX_READ_EVENT) { e = c->write; #if (NGX_READ_EVENT != POLLIN) event = POLLIN; #endif } else { e = c->read; #if (NGX_WRITE_EVENT != POLLOUT) event = POLLOUT; #endif } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "poll del event: fd:%d ev:%i", c->fd, event); if (e == NULL || e->index == NGX_INVALID_INDEX) { nevents--; if (ev->index < nevents) { ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "index: copy event %ui to %i", nevents, ev->index); event_list[ev->index] = event_list[nevents]; event_index[ev->index] = event_index[nevents]; c = event_index[ev->index]; if (c->fd == (ngx_socket_t) -1) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "unexpected last event"); } else { if (c->read->index == nevents) { c->read->index = ev->index; } if (c->write->index == nevents) { c->write->index = ev->index; } } } } else { ngx_log_debug1(NGX_LOG_DEBUG_EVENT, ev->log, 0, "poll del index: %i", e->index); event_list[e->index].events &= (short) ~event; } ev->index = NGX_INVALID_INDEX; return NGX_OK; } static ngx_int_t ngx_poll_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags) { int ready, revents; ngx_err_t err; ngx_uint_t i, found; ngx_event_t *ev; ngx_queue_t *queue; ngx_connection_t *c; /* NGX_TIMER_INFINITE == INFTIM */ #if (NGX_DEBUG0) if (cycle->log->log_level & NGX_LOG_DEBUG_ALL) { for (i = 0; i < nevents; i++) { ngx_log_debug3(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "poll: %ui: fd:%d ev:%04Xd", i, event_list[i].fd, event_list[i].events); } } #endif ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "poll timer: %M", timer); ready = WSAPoll(event_list, (u_int) nevents, (int) timer); err = (ready == -1) ? ngx_errno : 0; if (flags & NGX_UPDATE_TIME || ngx_event_timer_alarm) { ngx_time_update(); } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "poll ready %d of %ui", ready, nevents); if (err) { ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "WSAPoll() failed"); return NGX_ERROR; } if (ready == 0) { if (timer != NGX_TIMER_INFINITE) { return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "WSAPoll() returned no events without timeout"); return NGX_ERROR; } for (i = 0; i < nevents && ready; i++) { revents = event_list[i].revents; #if 1 ngx_log_debug4(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "poll: %ui: fd:%d ev:%04Xd rev:%04Xd", i, event_list[i].fd, event_list[i].events, revents); #else if (revents) { ngx_log_debug4(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "poll: %ui: fd:%d ev:%04Xd rev:%04Xd", i, event_list[i].fd, event_list[i].events, revents); } #endif if (revents & POLLNVAL) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "poll() error fd:%d ev:%04Xd rev:%04Xd", event_list[i].fd, event_list[i].events, revents); } if (revents & ~(POLLIN|POLLOUT|POLLERR|POLLHUP|POLLNVAL)) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "strange poll() events fd:%d ev:%04Xd rev:%04Xd", event_list[i].fd, event_list[i].events, revents); } if (event_list[i].fd == (ngx_socket_t) -1) { /* * the disabled event, a workaround for our possible bug, * see the comment below */ continue; } c = event_index[i]; if (c->fd == (ngx_socket_t) -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "unexpected event"); /* * it is certainly our fault and it should be investigated, * in the meantime we disable this event to avoid a CPU spinning */ if (i == nevents - 1) { nevents--; } else { event_list[i].fd = (ngx_socket_t) -1; } continue; } if (revents & (POLLERR|POLLHUP|POLLNVAL)) { /* * if the error events were returned, add POLLIN and POLLOUT * to handle the events at least in one active handler */ revents |= POLLIN|POLLOUT; } found = 0; if ((revents & POLLIN) && c->read->active) { found = 1; ev = c->read; ev->ready = 1; ev->available = -1; queue = ev->accept ? &ngx_posted_accept_events : &ngx_posted_events; ngx_post_event(ev, queue); } if ((revents & POLLOUT) && c->write->active) { found = 1; ev = c->write; ev->ready = 1; ngx_post_event(ev, &ngx_posted_events); } if (found) { ready--; continue; } } if (ready != 0) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "poll ready != events"); } return NGX_OK; } static char * ngx_poll_init_conf(ngx_cycle_t *cycle, void *conf) { ngx_event_conf_t *ecf; ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module); if (ecf->use != ngx_poll_module.ctx_index) { return NGX_CONF_OK; } #if (NGX_LOAD_WSAPOLL) if (!ngx_have_wsapoll) { ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "poll is not available on this platform"); return NGX_CONF_ERROR; } #endif return NGX_CONF_OK; }