Mercurial > hg > nginx
view src/os/win32/ngx_wsasend_chain.c @ 7583:efd71d49bde0
Events: available bytes calculation via ioctl(FIONREAD).
This makes it possible to avoid looping for a long time while working
with a fast enough peer when data are added to the socket buffer faster
than we are able to read and process them (ticket #1431). This is
basically what we already do on FreeBSD with kqueue, where information
about the number of bytes in the socket buffer is returned by
the kevent() call.
With other event methods rev->available is now set to -1 when the socket
is ready for reading. Later in ngx_recv() and ngx_recv_chain(), if
full buffer is received, real number of bytes in the socket buffer is
retrieved using ioctl(FIONREAD). Reading more than this number of bytes
ensures that even with edge-triggered event methods the event will be
triggered again, so it is safe to stop processing of the socket and
switch to other connections.
Using ioctl(FIONREAD) only after reading a full buffer is an optimization.
With this approach we only call ioctl(FIONREAD) when there are at least
two recv()/readv() calls.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 17 Oct 2019 16:02:19 +0300 |
parents | 2cd019520210 |
children | ecf2a9002b37 |
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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_WSABUFS 8 ngx_chain_t * ngx_wsasend_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit) { int rc; u_char *prev; u_long size, sent, send, prev_send; ngx_err_t err; ngx_event_t *wev; ngx_array_t vec; ngx_chain_t *cl; LPWSABUF wsabuf; WSABUF wsabufs[NGX_WSABUFS]; wev = c->write; if (!wev->ready) { return in; } /* the maximum limit size is the maximum u_long value - the page size */ if (limit == 0 || limit > (off_t) (NGX_MAX_UINT32_VALUE - ngx_pagesize)) { limit = NGX_MAX_UINT32_VALUE - ngx_pagesize; } send = 0; /* * WSABUFs must be 4-byte aligned otherwise * WSASend() will return undocumented WSAEINVAL error. */ vec.elts = wsabufs; vec.size = sizeof(WSABUF); vec.nalloc = NGX_WSABUFS; vec.pool = c->pool; for ( ;; ) { prev = NULL; wsabuf = NULL; prev_send = send; vec.nelts = 0; /* create the WSABUF and coalesce the neighbouring bufs */ for (cl = in; cl && vec.nelts < ngx_max_wsabufs && send < limit; cl = cl->next) { if (ngx_buf_special(cl->buf)) { continue; } size = cl->buf->last - cl->buf->pos; if (send + size > limit) { size = (u_long) (limit - send); } if (prev == cl->buf->pos) { wsabuf->len += cl->buf->last - cl->buf->pos; } else { wsabuf = ngx_array_push(&vec); if (wsabuf == NULL) { return NGX_CHAIN_ERROR; } wsabuf->buf = (char *) cl->buf->pos; wsabuf->len = cl->buf->last - cl->buf->pos; } prev = cl->buf->last; send += size; } sent = 0; rc = WSASend(c->fd, vec.elts, vec.nelts, &sent, 0, NULL, NULL); if (rc == -1) { err = ngx_errno; if (err == WSAEWOULDBLOCK) { ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "WSASend() not ready"); } else { wev->error = 1; ngx_connection_error(c, err, "WSASend() failed"); return NGX_CHAIN_ERROR; } } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "WSASend: fd:%d, s:%ul", c->fd, sent); c->sent += sent; in = ngx_chain_update_sent(in, sent); if (send - prev_send != sent) { wev->ready = 0; return in; } if (send >= limit || in == NULL) { return in; } } } ngx_chain_t * ngx_overlapped_wsasend_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit) { int rc; u_char *prev; u_long size, send, sent; ngx_err_t err; ngx_event_t *wev; ngx_array_t vec; ngx_chain_t *cl; LPWSAOVERLAPPED ovlp; LPWSABUF wsabuf; WSABUF wsabufs[NGX_WSABUFS]; wev = c->write; if (!wev->ready) { return in; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "wev->complete: %d", wev->complete); if (!wev->complete) { /* post the overlapped WSASend() */ /* the maximum limit size is the maximum u_long value - the page size */ if (limit == 0 || limit > (off_t) (NGX_MAX_UINT32_VALUE - ngx_pagesize)) { limit = NGX_MAX_UINT32_VALUE - ngx_pagesize; } /* * WSABUFs must be 4-byte aligned otherwise * WSASend() will return undocumented WSAEINVAL error. */ vec.elts = wsabufs; vec.nelts = 0; vec.size = sizeof(WSABUF); vec.nalloc = NGX_WSABUFS; vec.pool = c->pool; send = 0; prev = NULL; wsabuf = NULL; /* create the WSABUF and coalesce the neighbouring bufs */ for (cl = in; cl && vec.nelts < ngx_max_wsabufs && send < limit; cl = cl->next) { if (ngx_buf_special(cl->buf)) { continue; } size = cl->buf->last - cl->buf->pos; if (send + size > limit) { size = (u_long) (limit - send); } if (prev == cl->buf->pos) { wsabuf->len += cl->buf->last - cl->buf->pos; } else { wsabuf = ngx_array_push(&vec); if (wsabuf == NULL) { return NGX_CHAIN_ERROR; } wsabuf->buf = (char *) cl->buf->pos; wsabuf->len = cl->buf->last - cl->buf->pos; } prev = cl->buf->last; send += size; } ovlp = (LPWSAOVERLAPPED) &c->write->ovlp; ngx_memzero(ovlp, sizeof(WSAOVERLAPPED)); rc = WSASend(c->fd, vec.elts, vec.nelts, &sent, 0, ovlp, NULL); wev->complete = 0; if (rc == -1) { err = ngx_errno; if (err == WSA_IO_PENDING) { ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "WSASend() posted"); wev->active = 1; return in; } else { wev->error = 1; ngx_connection_error(c, err, "WSASend() failed"); return NGX_CHAIN_ERROR; } } else if (ngx_event_flags & NGX_USE_IOCP_EVENT) { /* * if a socket was bound with I/O completion port then * GetQueuedCompletionStatus() would anyway return its status * despite that WSASend() was already complete */ wev->active = 1; return in; } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "WSASend: fd:%d, s:%ul", c->fd, sent); } else { /* the overlapped WSASend() complete */ wev->complete = 0; wev->active = 0; if (ngx_event_flags & NGX_USE_IOCP_EVENT) { if (wev->ovlp.error) { ngx_connection_error(c, wev->ovlp.error, "WSASend() failed"); return NGX_CHAIN_ERROR; } sent = wev->available; } else { if (WSAGetOverlappedResult(c->fd, (LPWSAOVERLAPPED) &wev->ovlp, &sent, 0, NULL) == 0) { ngx_connection_error(c, ngx_socket_errno, "WSASend() or WSAGetOverlappedResult() failed"); return NGX_CHAIN_ERROR; } } } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "WSASend ovlp: fd:%d, s:%ul", c->fd, sent); c->sent += sent; in = ngx_chain_update_sent(in, sent); if (in) { wev->ready = 0; } else { wev->ready = 1; } return in; }