Mercurial > hg > nginx

comparison src/os/win32/ngx_wsarecv_chain.c @ 7583:efd71d49bde0

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
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 ec81934727a1
children ecf2a9002b37
comparison
equal deleted inserted replaced
7582:70749256af79 7583:efd71d49bde0
92 rev->error = 1; 92 rev->error = 1;
93 ngx_connection_error(c, err, "WSARecv() failed"); 93 ngx_connection_error(c, err, "WSARecv() failed");
94 return NGX_ERROR; 94 return NGX_ERROR;
95 } 95 }
96 96
97 #if (NGX_HAVE_FIONREAD)
98
99 if (rev->available >= 0 && bytes > 0) {
100 rev->available -= bytes;
101
102 /*
103 * negative rev->available means some additional bytes
104 * were received between kernel notification and WSARecv(),
105 * and therefore ev->ready can be safely reset even for
106 * edge-triggered event methods
107 */
108
109 if (rev->available < 0) {
110 rev->available = 0;
111 rev->ready = 0;
112 }
113
114 ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
115 "WSARecv: avail:%d", rev->available);
116
117 } else if (bytes == size) {
118
119 if (ngx_socket_nread(c->fd, &rev->available) == -1) {
120 rev->error = 1;
121 ngx_connection_error(c, ngx_socket_errno,
122 ngx_socket_nread_n " failed");
123 return NGX_ERROR;
124 }
125
126 ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
127 "WSARecv: avail:%d", rev->available);
128 }
129
130 #endif
131
97 if (bytes < size) { 132 if (bytes < size) {
98 rev->ready = 0; 133 rev->ready = 0;
99 } 134 }
100 135
101 if (bytes == 0) { 136 if (bytes == 0) {