mpid_ssend.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 "mpidimpl.h"

/* FIXME: HOMOGENEOUS SYSTEMS ONLY -- no data conversion is performed */

/*
 * MPID_Ssend()
 */
#undef FUNCNAME
#define FUNCNAME MPID_Ssend
#undef FCNAME
#define FCNAME MPIDI_QUOTE(FUNCNAME)
int MPID_Ssend(const void * buf, int count, MPI_Datatype datatype, int rank, int tag, MPID_Comm * comm, int context_offset,
	       MPID_Request ** request)
{
    MPIDI_msg_sz_t data_sz;
    int dt_contig;
    MPID_Request * sreq = NULL;
    MPIDI_VC * vc;
#if defined(MPID_USE_SEQUENCE_NUMBERS)
    MPID_Seqnum_t seqnum;
#endif    
    int mpi_errno = MPI_SUCCESS;
    MPIDI_STATE_DECL(MPID_STATE_MPID_SSEND);

    MPIDI_FUNC_ENTER(MPID_STATE_MPID_SSEND);

    MPIDI_DBG_PRINTF((10, FCNAME, "entering"));
    MPIDI_DBG_PRINTF((15, FCNAME, "rank=%d, tag=%d, context=%d", rank, tag, comm->context_id + context_offset));

    if (rank == comm->rank && comm->comm_kind != MPID_INTERCOMM)
    {
	mpi_errno = MPIDI_Isend_self(buf, count, datatype, rank, tag, comm, context_offset, MPIDI_REQUEST_TYPE_SSEND, &sreq);
#       if defined(MPICH_SINGLE_THREADED)
	{
	    if (sreq != NULL && sreq->cc != 0)
	    {
		MPIDI_ERR_PRINTF((FCNAME, "DEADLOCK - MPI_Ssend() to self, no matching received posted."));
		abort();
	    }
	}
#	endif
	goto fn_exit;
    }
    
    if (rank == MPI_PROC_NULL)
    {
	goto fn_exit;
    }

    MPIDI_CH3U_Datatype_get_info(count, datatype, dt_contig, data_sz);

    vc = comm->vcr[rank];
	
    MPIDI_CH3M_create_sreq(sreq, mpi_errno, goto fn_exit);
    MPIDI_Request_set_type(sreq, MPIDI_REQUEST_TYPE_SSEND);
    
    /* FIXME: Since the request is never returned to the user and they can't do things like cancel it or wait on it, we may not
       need to fill in all of the fields.  For example, it may be completely unnecessary to supply the matching information.  Also,
       some of the fields can be set after the message has been sent.  These issues should be looked at more closely when we are
       trying to squeeze those last few nanoseconds out of the code.  */
    
    if (data_sz == 0)
    {
	MPIDI_CH3_Pkt_t upkt;
	MPIDI_CH3_Pkt_eager_sync_send_t * const es_pkt = &upkt.eager_sync_send;

	MPIDI_DBG_PRINTF((15, FCNAME, "sending zero length message"));

	sreq->cc = 2;
	sreq->ch3.ca = MPIDI_CH3_CA_COMPLETE;
	
	es_pkt->type = MPIDI_CH3_PKT_EAGER_SYNC_SEND;
	es_pkt->match.rank = comm->rank;
	es_pkt->match.tag = tag;
	es_pkt->match.context_id = comm->context_id + context_offset;
	es_pkt->sender_req_id = sreq->handle;
	es_pkt->data_sz = 0;

	MPIDI_CH3U_VC_FAI_send_seqnum(vc, seqnum);
	MPIDI_CH3U_Pkt_set_seqnum(es_pkt, seqnum);
	MPIDI_CH3U_Request_set_seqnum(sreq, seqnum);
	
	MPIDI_CH3_iSend(vc, sreq, es_pkt, sizeof(*es_pkt));
	
	goto fn_exit;
    }
    
    /* FIXME: flow control: limit number of outstanding eager messsages containing data and need to be buffered by the receiver */

    /* FIXME: handle case where data_sz is greater than what can be stored in iov.MPID_IOV_LEN.  hand off to segment code? */
    
    if (data_sz + sizeof(MPIDI_CH3_Pkt_eager_sync_send_t) <= MPIDI_CH3_EAGER_MAX_MSG_SIZE)
    {
	MPIDI_CH3_Pkt_t upkt;
	MPIDI_CH3_Pkt_eager_sync_send_t * const es_pkt = &upkt.eager_sync_send;
	MPID_IOV iov[MPID_IOV_LIMIT];
	    
	sreq->cc = 2;
	sreq->ch3.ca = MPIDI_CH3_CA_COMPLETE;
	
	es_pkt->type = MPIDI_CH3_PKT_EAGER_SYNC_SEND;
	es_pkt->match.rank = comm->rank;
	es_pkt->match.tag = tag;
	es_pkt->match.context_id = comm->context_id + context_offset;
	es_pkt->sender_req_id = sreq->handle;
	es_pkt->data_sz = data_sz;

	iov[0].MPID_IOV_BUF = (void*)es_pkt;
	iov[0].MPID_IOV_LEN = sizeof(*es_pkt);

	if (dt_contig)
	{
	    MPIDI_DBG_PRINTF((15, FCNAME, "sending contiguous sync eager message, data_sz=" MPIDI_MSG_SZ_FMT, data_sz));
	    
	    iov[1].MPID_IOV_BUF = (void *) buf;
	    iov[1].MPID_IOV_LEN = data_sz;
	    
	    MPIDI_CH3U_VC_FAI_send_seqnum(vc, seqnum);
	    MPIDI_CH3U_Pkt_set_seqnum(es_pkt, seqnum);
	    MPIDI_CH3U_Request_set_seqnum(sreq, seqnum);
	    
	    MPIDI_CH3_iSendv(vc, sreq, iov, 2);
	}
	else
	{
	    int iov_n;
	    
	    MPIDI_DBG_PRINTF((15, FCNAME, "sending non-contiguous sync eager message, data_sz=" MPIDI_MSG_SZ_FMT, data_sz));
	    
	    MPID_Segment_init(buf, count, datatype, &sreq->ch3.segment);
	    sreq->ch3.segment_first = 0;
	    sreq->ch3.segment_size = data_sz;
	    
	    iov_n = MPID_IOV_LIMIT - 1;
	    mpi_errno = MPIDI_CH3U_Request_load_send_iov(sreq, &iov[1], &iov_n);
	    if (mpi_errno == MPI_SUCCESS)
	    {
		iov_n += 1;
		
		MPIDI_CH3U_VC_FAI_send_seqnum(vc, seqnum);
		MPIDI_CH3U_Pkt_set_seqnum(es_pkt, seqnum);
		MPIDI_CH3U_Request_set_seqnum(sreq, seqnum);
		
		MPIDI_CH3_iSendv(vc, sreq, iov, iov_n);
	    }
	    else
	    {
		MPIU_Object_set_ref(sreq, 0);
		MPIDI_CH3_Request_destroy(sreq);
		sreq = NULL;
	    }
	}
    }
    else
    {
	MPIDI_CH3_Pkt_t upkt;
	MPIDI_CH3_Pkt_rndv_req_to_send_t * const rts_pkt = &upkt.rndv_req_to_send;
	MPID_Request * rts_sreq;
	
	MPIDI_DBG_PRINTF((15, FCNAME, "sending rndv RTS, data_sz=" MPIDI_MSG_SZ_FMT, data_sz));
	    
	rts_pkt->type = MPIDI_CH3_PKT_RNDV_REQ_TO_SEND;
	rts_pkt->match.rank = comm->rank;
	rts_pkt->match.tag = tag;
	rts_pkt->match.context_id = comm->context_id + context_offset;
	rts_pkt->sender_req_id = sreq->handle;
	rts_pkt->data_sz = data_sz;

	MPIDI_CH3U_VC_FAI_send_seqnum(vc, seqnum);
	MPIDI_CH3U_Pkt_set_seqnum(rts_pkt, seqnum);
	MPIDI_CH3U_Request_set_seqnum(sreq, seqnum);
	
	rts_sreq = MPIDI_CH3_iStartMsg(vc, rts_pkt, sizeof(*rts_pkt));
	sreq->partner_request = rts_sreq;

	/* TODO: fill temporary IOV or pack temporary buffer after send to hide some latency.  This require synchronization because
           CTS could arrive and be processed before the above iSend completes (depending on the progress engine, threads, etc.). */
    }

  fn_exit:
    *request = sreq;
    if (sreq != NULL)
    {
	MPIDI_DBG_PRINTF((15, FCNAME, "request allocated, handle=0x%08x", sreq->handle));
    }
    MPIDI_DBG_PRINTF((10, FCNAME, "exiting"));
    MPIDI_FUNC_EXIT(MPID_STATE_MPID_SSEND);
    return mpi_errno;
}