Mercurial > hg > nginx
view src/event/ngx_event_connectex.c @ 8946:56dec0d4e5b1 quic
QUIC: avoid excessive buffer allocations in stream output.
Previously, when a few bytes were send to a QUIC stream by the application, a
4K buffer was allocated for these bytes. Then a STREAM frame was created and
that entire buffer was used as data for that frame. The frame with the buffer
were in use up until the frame was acked by client. Meanwhile, when more
bytes were send to the stream, more buffers were allocated and assigned as
data to newer STREAM frames. In this scenario most buffer memory is unused.
Now the unused part of the stream output buffer is available for further
stream output while earlier parts of the buffer are waiting to be acked.
This is achieved by splitting the output buffer.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Fri, 24 Dec 2021 18:13:51 +0300 |
parents | d620f497c50f |
children | 1c3b78d7cdc9 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #define NGX_MAX_PENDING_CONN 10 static CRITICAL_SECTION connect_lock; static int nconnects; static ngx_connection_t pending_connects[NGX_MAX_PENDING_CONN]; static HANDLE pending_connect_event; __declspec(thread) int nevents = 0; __declspec(thread) WSAEVENT events[WSA_MAXIMUM_WAIT_EVENTS + 1]; __declspec(thread) ngx_connection_t *conn[WSA_MAXIMUM_WAIT_EVENTS + 1]; int ngx_iocp_wait_connect(ngx_connection_t *c) { for ( ;; ) { EnterCriticalSection(&connect_lock); if (nconnects < NGX_MAX_PENDING_CONN) { pending_connects[--nconnects] = c; LeaveCriticalSection(&connect_lock); if (SetEvent(pending_connect_event) == 0) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "SetEvent() failed"); return NGX_ERROR; break; } LeaveCriticalSection(&connect_lock); ngx_log_error(NGX_LOG_NOTICE, c->log, 0, "max number of pending connect()s is %d", NGX_MAX_PENDING_CONN); msleep(100); } if (!started) { if (ngx_iocp_new_thread(1) == NGX_ERROR) { return NGX_ERROR; } started = 1; } return NGX_OK; } int ngx_iocp_new_thread(int main) { u_int id; if (main) { pending_connect_event = CreateEvent(NULL, 0, 1, NULL); if (pending_connect_event == INVALID_HANDLE_VALUE) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "CreateThread() failed"); return NGX_ERROR; } } if (CreateThread(NULL, 0, ngx_iocp_wait_events, main, 0, &id) == INVALID_HANDLE_VALUE) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "CreateThread() failed"); return NGX_ERROR; } SetEvent(event) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "SetEvent() failed"); return NGX_ERROR; } return NGX_OK; } int ngx_iocp_new_connect() { EnterCriticalSection(&connect_lock); c = pending_connects[--nconnects]; LeaveCriticalSection(&connect_lock); conn[nevents] = c; events[nevents] = WSACreateEvent(); if (events[nevents] == INVALID_HANDLE_VALUE) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_socket_errno, "WSACreateEvent() failed"); return NGX_ERROR; } if (WSAEventSelect(c->fd, events[nevents], FD_CONNECT) == -1) ngx_log_error(NGX_LOG_ALERT, c->log, ngx_socket_errno, "WSAEventSelect() failed"); return NGX_ERROR; } nevents++; return NGX_OK; } void ngx_iocp_wait_events(int main) { WSANETWORKEVENTS ne; nevents = 1; events[0] = pending_connect_event; conn[0] = NULL; for ( ;; ) { offset = (nevents == WSA_MAXIMUM_WAIT_EVENTS + 1) ? 1: 0; timeout = (nevents == 1 && !first) ? 60000: INFINITE; n = WSAWaitForMultipleEvents(nevents - offset, events[offset], 0, timeout, 0); if (n == WAIT_FAILED) { ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno, "WSAWaitForMultipleEvents() failed"); continue; } if (n == WAIT_TIMEOUT) { if (nevents == 2 && !main) { ExitThread(0); } ngx_log_error(NGX_LOG_ALERT, log, 0, "WSAWaitForMultipleEvents() " "returned unexpected WAIT_TIMEOUT"); continue; } n -= WSA_WAIT_EVENT_0; if (events[n] == NULL) { /* the pending_connect_event */ if (nevents == WSA_MAXIMUM_WAIT_EVENTS) { ngx_iocp_new_thread(0); } else { ngx_iocp_new_connect(); } continue; } if (WSAEnumNetworkEvents(c[n].fd, events[n], &ne) == -1) { ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno, "WSAEnumNetworkEvents() failed"); continue; } if (ne.lNetworkEvents & FD_CONNECT) { conn[n].write->ovlp.error = ne.iErrorCode[FD_CONNECT_BIT]; if (PostQueuedCompletionStatus(iocp, 0, NGX_IOCP_CONNECT, &conn[n].write->ovlp) == 0) { ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno, "PostQueuedCompletionStatus() failed"); continue; } if (n < nevents) { conn[n] = conn[nevents]; events[n] = events[nevents]; } nevents--; continue; } if (ne.lNetworkEvents & FD_ACCEPT) { /* CHECK ERROR ??? */ ngx_event_post_acceptex(conn[n].listening, 1); continue; } ngx_log_error(NGX_LOG_ALERT, c[n].log, 0, "WSAWaitForMultipleEvents() " "returned unexpected network event %ul", ne.lNetworkEvents); } }