view src/event/ngx_event_connectex.c @ 4233:aae172db7ac8

Event pipe: reduced number of file buffers used. If possible we now just extend already present file buffer in p->out chain instead of keeping ngx_buf_t for each buffer we've flushed to disk. This saves about 120 bytes of memory per buffer flushed to disk, and resolves high CPU usage observed in edge cases (due to coalescing these buffers on send).
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 31 Oct 2011 09:54:55 +0000
parents a88a3e4e158f
children d620f497c50f
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 */


#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);
    }
}