ch3_istartmsg.c

刚才是说明 现在是安装程序在 LINUX环境下进行编程的MPICH安装文件

/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*
 *  (C) 2001 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

#include "mpidi_ch3_impl.h"

static MPID_Request * create_request(void * hdr, int hdr_sz, int nb)
{
    MPID_Request * sreq;
    MPIDI_STATE_DECL(MPID_STATE_CREATE_REQUEST);

    MPIDI_FUNC_ENTER(MPID_STATE_CREATE_REQUEST);

    sreq = MPIDI_CH3_Request_create();
    assert(sreq != NULL);
    MPIU_Object_set_ref(sreq, 2);
    sreq->kind = MPID_REQUEST_SEND;
    /* memcpy(&sreq->tcp.pkt, hdr, hdr_sz); */
    assert(hdr_sz == sizeof(MPIDI_CH3_Pkt_t));
    sreq->tcp.pkt = *(MPIDI_CH3_Pkt_t *) hdr;
    sreq->ch3.iov[0].MPID_IOV_BUF = (char *) &sreq->tcp.pkt + nb;
    sreq->ch3.iov[0].MPID_IOV_LEN = hdr_sz - nb;
    sreq->ch3.iov_count = 1;
    sreq->tcp.iov_offset = 0;
    sreq->ch3.ca = MPIDI_CH3_CA_COMPLETE;
    
    MPIDI_FUNC_EXIT(MPID_STATE_CREATE_REQUEST);
    return sreq;
}

/*
 * MPIDI_CH3_iStartMsg() attempts to send the message immediately.  If the
 * entire message is successfully sent, then NULL is returned.  Otherwise a
 * request is allocated, the header is copied into the request, and a pointer
 * to the request is returned.  An error condition also results in a request be
 * allocated and the errror being returned in the status field of the
 * request.
 */
#undef FUNCNAME
#define FUNCNAME MPIDI_CH3_iStartMsg
#undef FCNAME
#define FCNAME MPIDI_QUOTE(FUNCNAME)
MPID_Request * MPIDI_CH3_iStartMsg(MPIDI_VC * vc, void * hdr, int hdr_sz)
{
    MPID_Request * sreq = NULL;
    MPIDI_STATE_DECL(MPID_STATE_MPIDI_CH3_ISTARTMSG);
    MPIDI_STATE_DECL(MPID_STATE_WRITE);

    MPIDI_FUNC_ENTER(MPID_STATE_MPIDI_CH3_ISTARTMSG);
    
    MPIDI_DBG_PRINTF((50, FCNAME, "entering"));
    assert(hdr_sz <= sizeof(MPIDI_CH3_Pkt_t));

    /* The TCP implementation uses a fixed length header, the size of which is
       the maximum of all possible packet headers */
    hdr_sz = sizeof(MPIDI_CH3_Pkt_t);
    
    if (vc->tcp.state == MPIDI_CH3I_VC_STATE_CONNECTED) /* MT */
    {
	/* Connection already formed.  If send queue is empty attempt to send
           data, queuing any unsent data. */
	if (MPIDI_CH3I_SendQ_empty(vc)) /* MT */
	{
	    int nb;

	    /* MT - need some signalling to lock down our right to use the
               channel, thus insuring that the progress engine does also try to
               write */
	    do
	    {
		MPIDI_FUNC_ENTER(MPID_STATE_WRITE);
		nb = write(vc->tcp.fd, hdr, hdr_sz);
		MPIDI_FUNC_EXIT(MPID_STATE_WRITE);
	    }
	    while (nb == -1 && errno == EINTR);
	    
	    if (nb == hdr_sz)
	    {
		MPIDI_DBG_PRINTF((55, FCNAME, "data sent immediately"));
		/* done.  get us out of here as quickly as possible. */
	    }
	    else if (nb >= 0)
	    {
		MPIDI_DBG_PRINTF((55, FCNAME,
				  "send delayed, request enqueued"));
		sreq = create_request(hdr, hdr_sz, nb);
		MPIDI_CH3I_SendQ_enqueue_head(vc, sreq);
		MPIDI_CH3I_TCP_post_write(vc, sreq);
	    }
	    else if (errno == EAGAIN || errno == EWOULDBLOCK ||
		     errno == ENOMEM)
	    {
		MPIDI_DBG_PRINTF((55, FCNAME, "send failed, errno=%d:%s, "
				  "request enqueued", errno, strerror(errno)));
		sreq = create_request(hdr, hdr_sz, 0);
		MPIDI_CH3I_SendQ_enqueue(vc, sreq);
		MPIDI_CH3I_TCP_post_write(vc, sreq);
	    }
	    else
	    {
		MPIDI_DBG_PRINTF((55, FCNAME, "ERROR - connection failed, "
				  "errno=%d:%s", errno, strerror(errno)));
		sreq = MPIDI_CH3_Request_create();
		assert(sreq != NULL);
		sreq->kind = MPID_REQUEST_SEND;
		sreq->cc = 0;
		/* TODO: Create an appropriate error message based on the value
                   of errno */
		sreq->status.MPI_ERROR = MPI_ERR_INTERN;
	    }
	}
	else
	{
	    MPIDI_DBG_PRINTF((55, FCNAME,
			      "send in progress, request enqueued"));
	    sreq = create_request(hdr, hdr_sz, 0);
	    MPIDI_CH3I_SendQ_enqueue(vc, sreq);
	}
    }
    else if (vc->tcp.state == MPIDI_CH3I_VC_STATE_UNCONNECTED) /* MT */
    {
	MPIDI_DBG_PRINTF((55, FCNAME, "unconnected.  requesting connection "
			  "and enqueuing send request"));
	
	/* Form a new connection */
	MPIDI_CH3I_TCP_post_connect(vc);

	/* queue the data so it can be sent after the connection is formed */
	sreq = create_request(hdr, hdr_sz, 0);
	MPIDI_CH3I_SendQ_enqueue(vc, sreq);
    }
    else if (vc->tcp.state != MPIDI_CH3I_VC_STATE_FAILED)
    {
	/* Unable to send data at the moment, so queue it for later */
	MPIDI_DBG_PRINTF((55, FCNAME, "forming connection, request enqueued"));
	sreq = create_request(hdr, hdr_sz, 0);
	MPIDI_CH3I_SendQ_enqueue(vc, sreq);
    }
    else
    {
	/* Connection failed, so allocate a request and return an error. */
	MPIDI_DBG_PRINTF((55, FCNAME, "ERROR - connection failed"));
	sreq = MPIDI_CH3_Request_create();
	assert(sreq != NULL);
	sreq->kind = MPID_REQUEST_SEND;
	sreq->cc = 0;
	/* TODO: Create an appropriate error message */
	sreq->status.MPI_ERROR = MPI_ERR_INTERN;
    }
    
    MPIDI_DBG_PRINTF((50, FCNAME, "exiting"));
    MPIDI_FUNC_EXIT(MPID_STATE_MPIDI_CH3_ISTARTMSG);
    return sreq;
}