ch3u_rma_sync.c

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

#include "mpidimpl.h"
#include "mpidrma.h"

#ifdef USE_MPIU_INSTR
MPIU_INSTR_DURATION_DECL(winfence_clearlock);
MPIU_INSTR_DURATION_DECL(winfence_rs);
MPIU_INSTR_DURATION_DECL(winfence_issue);
MPIU_INSTR_DURATION_DECL(winfence_complete);
MPIU_INSTR_DURATION_DECL(winfence_wait);
MPIU_INSTR_DURATION_DECL(winfence_block);
MPIU_INSTR_COUNTER_DECL(winfence_reqs);
MPIU_INSTR_COUNTER_DECL(winunlock_reqs);
MPIU_INSTR_COUNTER_DECL(wincomplete_reqs);
MPIU_INSTR_DURATION_DECL(winpost_clearlock);
MPIU_INSTR_DURATION_DECL(winpost_sendsync);
MPIU_INSTR_DURATION_DECL(winstart_clearlock);
MPIU_INSTR_DURATION_DECL(wincomplete_issue);
MPIU_INSTR_DURATION_DECL(wincomplete_complete);
MPIU_INSTR_DURATION_DECL(wincomplete_recvsync);
MPIU_INSTR_DURATION_DECL(wincomplete_block);
MPIU_INSTR_DURATION_DECL(winwait_wait);
MPIU_INSTR_DURATION_DECL(winlock_getlocallock);
MPIU_INSTR_DURATION_DECL(winunlock_getlock);
MPIU_INSTR_DURATION_DECL(winunlock_issue);
MPIU_INSTR_DURATION_DECL(winunlock_complete);
MPIU_INSTR_DURATION_DECL(winunlock_block);
MPIU_INSTR_DURATION_DECL(lockqueue_alloc);
MPIU_INSTR_DURATION_DECL(rmapkt_acc);
MPIU_INSTR_DURATION_DECL(rmapkt_acc_predef);
MPIU_INSTR_DURATION_DECL(rmapkt_acc_immed);
MPIU_INSTR_DURATION_DECL(rmapkt_acc_immed_op);
MPIU_INSTR_DURATION_DECL(rmapkt_cas);
MPIU_INSTR_DURATION_DECL(rmapkt_fop);
MPIU_INSTR_DURATION_DECL(rmapkt_get_accum);
MPIU_INSTR_DURATION_EXTERN_DECL(rmaqueue_alloc);
MPIU_INSTR_DURATION_EXTERN_DECL(rmaqueue_set);
void MPIDI_CH3_RMA_InitInstr(void);

void MPIDI_CH3_RMA_InitInstr(void)
{
    MPIU_INSTR_DURATION_INIT(lockqueue_alloc,0,"Allocate Lock Queue element");
    MPIU_INSTR_DURATION_INIT(winfence_clearlock,1,"WIN_FENCE:Clear prior lock");
    MPIU_INSTR_DURATION_INIT(winfence_rs,0,"WIN_FENCE:ReduceScatterBlock");
    MPIU_INSTR_DURATION_INIT(winfence_issue,2,"WIN_FENCE:Issue RMA ops");
    MPIU_INSTR_DURATION_INIT(winfence_complete,1,"WIN_FENCE:Complete RMA ops");
    MPIU_INSTR_DURATION_INIT(winfence_wait,1,"WIN_FENCE:Wait for ops from other processes");
    MPIU_INSTR_DURATION_INIT(winfence_block,0,"WIN_FENCE:Wait for any progress");
    MPIU_INSTR_COUNTER_INIT(winfence_reqs,"WIN_FENCE:Pending requests");
    MPIU_INSTR_COUNTER_INIT(winunlock_reqs,"WIN_UNLOCK:Pending requests");
    MPIU_INSTR_COUNTER_INIT(wincomplete_reqs,"WIN_COMPLETE:Pending requests");
    MPIU_INSTR_DURATION_INIT(winpost_clearlock,1,"WIN_POST:Clear prior lock");
    MPIU_INSTR_DURATION_INIT(winpost_sendsync,1,"WIN_POST:Senc sync messages");
    MPIU_INSTR_DURATION_INIT(winstart_clearlock,1,"WIN_START:Clear prior lock");
    MPIU_INSTR_DURATION_INIT(wincomplete_recvsync,1,"WIN_COMPLETE:Recv sync messages");
    MPIU_INSTR_DURATION_INIT(wincomplete_issue,2,"WIN_COMPLETE:Issue RMA ops");
    MPIU_INSTR_DURATION_INIT(wincomplete_complete,1,"WIN_COMPLETE:Complete RMA ops");
    MPIU_INSTR_DURATION_INIT(wincomplete_block,0,"WIN_COMPLETE:Wait for any progress");
    MPIU_INSTR_DURATION_INIT(winwait_wait,1,"WIN_WAIT:Wait for ops from other processes");
    MPIU_INSTR_DURATION_INIT(winlock_getlocallock,0,"WIN_LOCK:Get local lock");
    MPIU_INSTR_DURATION_INIT(winunlock_issue,2,"WIN_UNLOCK:Issue RMA ops");
    MPIU_INSTR_DURATION_INIT(winunlock_complete,1,"WIN_UNLOCK:Complete RMA ops");
    MPIU_INSTR_DURATION_INIT(winunlock_getlock,0,"WIN_UNLOCK:Acquire lock");
    MPIU_INSTR_DURATION_INIT(winunlock_block,0,"WIN_UNLOCK:Wait for any progress");
    MPIU_INSTR_DURATION_INIT(rmapkt_acc,0,"RMA:PKTHANDLER for Accumulate");
    MPIU_INSTR_DURATION_INIT(rmapkt_acc_predef,0,"RMA:PKTHANDLER for Accumulate: predef dtype");
    MPIU_INSTR_DURATION_INIT(rmapkt_acc_immed,0,"RMA:PKTHANDLER for Accum immed");
    MPIU_INSTR_DURATION_INIT(rmapkt_acc_immed_op,0,"RMA:PKTHANDLER for Accum immed operation");
    MPIU_INSTR_DURATION_INIT(rmapkt_cas,0,"RMA:PKTHANDLER for Compare-and-swap");
    MPIU_INSTR_DURATION_INIT(rmapkt_fop,0,"RMA:PKTHANDLER for Fetch-and-op");
    MPIU_INSTR_DURATION_INIT(rmapkt_get_accum,0,"RMA:PKTHANDLER for Get-Accumulate");
}

/* These are used to use a common routine to complete lists of RMA 
   operations with a single routine, while collecting data that 
   distinguishes between different synchronization modes.  This is not
   thread-safe; the best choice for thread-safety is to eliminate this
   ability to discriminate between the different types of RMA synchronization.
*/
static MPIU_INSTR_Duration_count *list_complete;  /* outer */
static MPIU_INSTR_Duration_count *list_block;     /* Inner; while waiting */

#endif

/*
 * These routines provide a default implementation of the MPI RMA operations
 * in terms of the low-level, two-sided channel operations.  A channel
 * may override these functions, on a per-window basis, by overriding
 * the MPID functions in the RMAFns section of MPID_Win object.
 */

#define SYNC_POST_TAG 100

static int MPIDI_CH3I_Send_lock_msg(int dest, int lock_type, MPID_Win *win_ptr);
static int MPIDI_CH3I_Send_unlock_msg(int dest, MPID_Win *win_ptr);
static int MPIDI_CH3I_Send_flush_msg(int dest, MPID_Win *win_ptr);
static int MPIDI_CH3I_Wait_for_lock_granted(MPID_Win *win_ptr, int target_rank);
static int MPIDI_CH3I_Acquire_local_lock(MPID_Win *win_ptr, int lock_mode);
static int MPIDI_CH3I_Send_rma_msg(MPIDI_RMA_Op_t * rma_op, MPID_Win * win_ptr,
				   MPI_Win source_win_handle, 
				   MPI_Win target_win_handle, 
				   MPIDI_RMA_dtype_info * dtype_info, 
				   void ** dataloop, MPID_Request ** request);
static int MPIDI_CH3I_Recv_rma_msg(MPIDI_RMA_Op_t * rma_op, MPID_Win * win_ptr,
				   MPI_Win source_win_handle, 
				   MPI_Win target_win_handle, 
				   MPIDI_RMA_dtype_info * dtype_info, 
				   void ** dataloop, MPID_Request ** request); 
static int MPIDI_CH3I_Send_contig_acc_msg(MPIDI_RMA_Op_t *, MPID_Win *,
					  MPI_Win, MPI_Win, MPID_Request ** );
static int MPIDI_CH3I_Send_immed_rmw_msg(MPIDI_RMA_Op_t *, MPID_Win *,
                                         MPI_Win, MPI_Win, MPID_Request ** );
static int MPIDI_CH3I_Do_passive_target_rma(MPID_Win *win_ptr, int target_rank,
                                            int *wait_for_rma_done_pkt,
                                            int unlock_target);
static int MPIDI_CH3I_Send_lock_put_or_acc(MPID_Win *, int);
static int MPIDI_CH3I_Send_lock_get(MPID_Win *, int);
static int MPIDI_CH3I_RMAListComplete(MPID_Win *win_ptr,
                                      MPIDI_RMA_Ops_list_t *ops_list);
static int MPIDI_CH3I_RMAListPartialComplete(MPID_Win *win_ptr,
                                             MPIDI_RMA_Ops_list_t *ops_list,
                                             MPIDI_RMA_Op_t *last_elm, int *nDone);

static int create_datatype(const MPIDI_RMA_dtype_info *dtype_info,
                           const void *dataloop, MPI_Aint dataloop_sz,
                           const void *o_addr, int o_count,
			   MPI_Datatype o_datatype,
                           MPID_Datatype **combined_dtp);

/* Issue an RMA operation -- Before calling this macro, you must define the
 * MPIDI_CH3I_TRACK_RMA_WRITE helper macro.  This macro defines any extra action
 * that should be taken when a write (put/acc) operation is encountered. */
#define MPIDI_CH3I_ISSUE_RMA_OP(op_ptr_, win_ptr_, source_win_handle_, target_win_handle_,err_) \
    do {                                                                                        \
    switch ((op_ptr_)->type)                                                                    \
    {                                                                                           \
        case (MPIDI_RMA_PUT):                                                                   \
        case (MPIDI_RMA_ACCUMULATE):                                                            \
            MPIDI_CH3I_TRACK_RMA_WRITE(op_ptr_, win_ptr_);                                      \
            (err_) = MPIDI_CH3I_Send_rma_msg((op_ptr_), (win_ptr_), (source_win_handle_),       \
                                                (target_win_handle_), &(op_ptr_)->dtype_info,   \
                                                &(op_ptr_)->dataloop, &(op_ptr_)->request);     \
            if (err_) { MPIU_ERR_POP(err_); }                                                   \
            break;                                                                              \
        case (MPIDI_RMA_GET_ACCUMULATE):                                                        \
            if ((op_ptr_)->op == MPI_NO_OP) {                                                   \
                /* Note: Origin arguments are ignored for NO_OP, so we don't                    \
                 * need to release a ref to the origin datatype. */                             \
                                                                                                \
                /* Convert the GAcc to a Get */                                                 \
                (op_ptr_)->type            = MPIDI_RMA_GET;                                     \
                (op_ptr_)->origin_addr     = (op_ptr_)->result_addr;                            \
                (op_ptr_)->origin_count    = (op_ptr_)->result_count;                           \
                (op_ptr_)->origin_datatype = (op_ptr_)->result_datatype;                        \
                                                                                                \
                (err_) = MPIDI_CH3I_Recv_rma_msg((op_ptr_), (win_ptr_), (source_win_handle_),   \
                                                    (target_win_handle_), &(op_ptr_)->dtype_info,\
                                                    &(op_ptr_)->dataloop, &(op_ptr_)->request); \
            } else {                                                                            \
                MPIDI_CH3I_TRACK_RMA_WRITE(op_ptr_, win_ptr_);                                  \
                (err_) = MPIDI_CH3I_Send_rma_msg((op_ptr_), (win_ptr_), (source_win_handle_),   \
                                                    (target_win_handle_), &(op_ptr_)->dtype_info,\
                                                    &(op_ptr_)->dataloop, &(op_ptr_)->request); \
            }                                                                                   \
            if (err_) { MPIU_ERR_POP(err_); }                                                   \
            break;                                                                              \
        case MPIDI_RMA_ACC_CONTIG:                                                              \
            MPIDI_CH3I_TRACK_RMA_WRITE(op_ptr_, win_ptr_);                                      \
            (err_) = MPIDI_CH3I_Send_contig_acc_msg((op_ptr_), (win_ptr_),                      \
                                                       (source_win_handle_), (target_win_handle_),\
                                                       &(op_ptr_)->request );                   \
            if (err_) { MPIU_ERR_POP(err_); }                                                   \
            break;                                                                              \
        case (MPIDI_RMA_GET):                                                                   \
            (err_) = MPIDI_CH3I_Recv_rma_msg((op_ptr_), (win_ptr_),                             \
                                                (source_win_handle_), (target_win_handle_),     \
                                                &(op_ptr_)->dtype_info,                         \
                                                &(op_ptr_)->dataloop, &(op_ptr_)->request);     \
            if (err_) { MPIU_ERR_POP(err_); }                                                   \
            break;                                                                              \
        case (MPIDI_RMA_COMPARE_AND_SWAP):                                                      \
        case (MPIDI_RMA_FETCH_AND_OP):                                                          \
            MPIDI_CH3I_TRACK_RMA_WRITE(op_ptr_, win_ptr_);                                      \
            (err_) = MPIDI_CH3I_Send_immed_rmw_msg((op_ptr_), (win_ptr_),                       \
                                                      (source_win_handle_), (target_win_handle_),\
                                                      &(op_ptr_)->request );                    \
            if (err_) { MPIU_ERR_POP(err_); }                                                   \
            break;                                                                              \
                                                                                                \
        default:                                                                                \
            MPIU_ERR_SETANDJUMP(err_,MPI_ERR_OTHER,"**winInvalidOp");                           \
    }                                                                                           \
    } while (0)


#undef FUNCNAME
#define FUNCNAME MPIDI_Win_fence
#undef FCNAME
#define FCNAME MPIDI_QUOTE(FUNCNAME)
int MPIDI_Win_fence(int assert, MPID_Win *win_ptr)
{
    int mpi_errno = MPI_SUCCESS;
    int comm_size;
    int *rma_target_proc, *nops_to_proc, i, total_op_count, *curr_ops_cnt;
    MPIDI_RMA_Op_t *curr_ptr;
    MPIDI_RMA_Ops_list_t *ops_list;
    MPID_Comm *comm_ptr;
    MPI_Win source_win_handle, target_win_handle;
    MPID_Progress_state progress_state;
    int errflag = FALSE;
    MPIU_CHKLMEM_DECL(3);
    MPIDI_STATE_DECL(MPID_STATE_MPIDI_WIN_FENCE);

    MPIDI_RMA_FUNC_ENTER(MPID_STATE_MPIDI_WIN_FENCE);

    MPIU_ERR_CHKANDJUMP(win_ptr->epoch_state != MPIDI_EPOCH_NONE &&
                        win_ptr->epoch_state != MPIDI_EPOCH_FENCE,
                        mpi_errno, MPI_ERR_RMA_SYNC, "**rmasync");

    /* In case this process was previously the target of passive target rma
     * operations, we need to take care of the following...
     * Since we allow MPI_Win_unlock to return without a done ack from
     * the target in the case of multiple rma ops and exclusive lock,
     * we need to check whether there is a lock on the window, and if
     * there is a lock, poke the progress engine until the operartions
     * have completed and the lock is released. */
    if (win_ptr->current_lock_type != MPID_LOCK_NONE)
    {
	MPIU_INSTR_DURATION_START(winfence_clearlock);
	MPID_Progress_start(&progress_state);
	while (win_ptr->current_lock_type != MPID_LOCK_NONE)
	{
	    /* poke the progress engine */
	    mpi_errno = MPID_Progress_wait(&progress_state);
	    /* --BEGIN ERROR HANDLING-- */
	    if (mpi_errno != MPI_SUCCESS) {
		MPID_Progress_end(&progress_state);
		MPIU_ERR_SETANDJUMP(mpi_errno,MPI_ERR_OTHER,"**winnoprogress");
	    }
	    /* --END ERROR HANDLING-- */
	    MPIU_INSTR_DURATION_INCR(winfence_clearlock,0,1);
	}
	MPID_Progress_end(&progress_state);
	MPIU_INSTR_DURATION_END(winfence_clearlock);
    }

    /* Note that the NOPRECEDE and NOSUCCEED must be specified by all processes
       in the window's group if any specify it */
    if (assert & MPI_MODE_NOPRECEDE)
    {
        /* Error: Operations were issued and the user claimed NOPRECEDE */
        MPIU_ERR_CHKANDJUMP(win_ptr->epoch_state == MPIDI_EPOCH_FENCE,
                            mpi_errno, MPI_ERR_RMA_SYNC, "**rmasync");

	win_ptr->fence_issued = (assert & MPI_MODE_NOSUCCEED) ? 0 : 1;
	goto fn_exit;
    }
    
    if (win_ptr->fence_issued == 0)
    {
	/* win_ptr->fence_issued == 0 means either this is the very first
	   call to fence or the preceding fence had the
	   MPI_MODE_NOSUCCEED assert. 

           If this fence has MPI_MODE_NOSUCCEED, do nothing and return.
	   Otherwise just increment the fence count and return. */

	if (!(assert & MPI_MODE_NOSUCCEED)) win_ptr->fence_issued = 1;
    }
    else
    {
	int nRequest = 0;
	int nRequestNew = 0;
	MPIU_INSTR_DURATION_START(winfence_rs);
	/* This is the second or later fence. Do all the preceding RMA ops. */
	comm_ptr = win_ptr->comm_ptr;
	/* First inform every process whether it is a target of RMA
	   ops from this process */
	comm_size = comm_ptr->local_size;

	MPIU_CHKLMEM_MALLOC(rma_target_proc, int *, comm_size*sizeof(int),
			    mpi_errno, "rma_target_proc");
	for (i=0; i<comm_size; i++) rma_target_proc[i] = 0;
	
	/* keep track of no. of ops to each proc. Needed for knowing
	   whether or not to decrement the completion counter. The
	   completion counter is decremented only on the last
	   operation. */
	MPIU_CHKLMEM_MALLOC(nops_to_proc, int *, comm_size*sizeof(int),
			    mpi_errno, "nops_to_proc");
	for (i=0; i<comm_size; i++) nops_to_proc[i] = 0;

        /* Note, active target uses the following ops list, and passive
           target uses win_ptr->targets[..] */
        ops_list = &win_ptr->at_rma_ops_list;

	/* set rma_target_proc[i] to 1 if rank i is a target of RMA
	   ops from this process */
	total_op_count = 0;
        curr_ptr = MPIDI_CH3I_RMA_Ops_head(ops_list);
	while (curr_ptr != NULL)
	{
	    total_op_count++;
	    rma_target_proc[curr_ptr->target_rank] = 1;
	    nops_to_proc[curr_ptr->target_rank]++;
	    curr_ptr = curr_ptr->next;
	}
	
	MPIU_CHKLMEM_MALLOC(curr_ops_cnt, int *, comm_size*sizeof(int),
			    mpi_errno, "curr_ops_cnt");
	for (i=0; i<comm_size; i++) curr_ops_cnt[i] = 0;
	/* do a reduce_scatter_block (with MPI_SUM) on rma_target_proc. 
	   As a result,
	   each process knows how many other processes will be doing
	   RMA ops on its window */  
            
	/* first initialize the completion counter. */
	win_ptr->my_counter = comm_size;
            
	mpi_errno = MPIR_Reduce_scatter_block_impl(MPI_IN_PLACE, rma_target_proc, 1,
                                                   MPI_INT, MPI_SUM, comm_ptr, &errflag);
	MPIU_INSTR_DURATION_END(winfence_rs);
	/* result is stored in rma_target_proc[0] */
	if (mpi_errno) { MPIU_ERR_POP(mpi_errno); }
        MPIU_ERR_CHKANDJUMP(errflag, mpi_errno, MPI_ERR_OTHER, "**coll_fail");

	/* Set the completion counter */
	/* FIXME: MT: this needs to be done atomically because other
	   procs have the address and could decrement it. */
	win_ptr->my_counter = win_ptr->my_counter - comm_size + 
	    rma_target_proc[0];  

	MPIU_INSTR_DURATION_START(winfence_issue);
	MPIU_INSTR_DURATION_INCR(winfence_issue,0,total_op_count);
	MPIU_INSTR_DURATION_MAX(winfence_issue,1,total_op_count);
	MPIU_INSTR_COUNTER_RESET(winfence_reqs);
	i = 0;
        curr_ptr = MPIDI_CH3I_RMA_Ops_head(ops_list);
	while (curr_ptr != NULL)
	{
	    /* The completion counter at the target is decremented only on 
	       the last RMA operation. We indicate the last operation by 
	       passing the source_win_handle only on the last operation. 
	       Otherwise, we pass NULL */
	    if (curr_ops_cnt[curr_ptr->target_rank] ==
		nops_to_proc[curr_ptr->target_rank] - 1) 
		source_win_handle = win_ptr->handle;
	    else 
		source_win_handle = MPI_WIN_NULL;
	    
	    target_win_handle = win_ptr->all_win_handles[curr_ptr->target_rank];

#define MPIDI_CH3I_TRACK_RMA_WRITE(op_ptr_, win_ptr_) /* Not used by active mode */
            MPIDI_CH3I_ISSUE_RMA_OP(curr_ptr, win_ptr, source_win_handle, target_win_handle, mpi_errno);
#undef MPIDI_CH3I_TRACK_RMA_WRITE

	    i++;
	    curr_ops_cnt[curr_ptr->target_rank]++;
	    /* If the request is null, we can remove it immediately */
	    if (!curr_ptr->request) {
                MPIDI_CH3I_RMA_Ops_free_and_next(ops_list, &curr_ptr);
	    }
	    else  {
		nRequest++;
		MPIU_INSTR_COUNTER_INCR(winfence_reqs,1);
		curr_ptr    = curr_ptr->next;
		/* The test on the difference is to reduce the number
		   of times the partial complete routine is called. Without
		   this, significant overhead is added once the
		   number of requests exceeds the threshold, since the
		   number that are completed in a call may be small. */
		if (nRequest > MPIR_PARAM_RMA_NREQUEST_THRESHOLD && 
		    nRequest - nRequestNew > MPIR_PARAM_RMA_NREQUEST_NEW_THRESHOLD) {
		    int nDone = 0;
                    MPIDI_CH3I_RMAListPartialComplete(win_ptr, ops_list, curr_ptr, &nDone);
		    /* if (nDone > 0) printf( "nDone = %d\n", nDone ); */
		    nRequest -= nDone;
		    nRequestNew = nRequest;
		}
	    }
	}
	MPIU_INSTR_DURATION_END(winfence_issue);

	/* We replaced a loop over an array of requests with a list of the
	   incomplete requests.  The reason to do 
	   that is for long lists - processing the entire list until
	   all are done introduces a potentially n^2 time.  In 
	   testing with test/mpi/perf/manyrma.c , the number of iterations
	   within the "while (total_op_count) was O(total_op_count).
	   
	   Another alternative is to create a more compressed list (storing
	   only the necessary information, reducing the number of cache lines
	   needed while looping through the requests.
	*/
	if (total_op_count)
	{ 
	    MPIU_INSTR_STMT(list_complete=MPIU_INSTR_GET_VAR(winfence_complete));
	    MPIU_INSTR_STMT(list_block=MPIU_INSTR_GET_VAR(winfence_block));
            mpi_errno = MPIDI_CH3I_RMAListComplete(win_ptr, ops_list);
	}

        MPIU_Assert(MPIDI_CH3I_RMA_Ops_isempty(ops_list));
	
	/* wait for all operations from other processes to finish */
	if (win_ptr->my_counter)
	{
	    MPIU_INSTR_DURATION_START(winfence_wait);
	    MPID_Progress_start(&progress_state);
	    while (win_ptr->my_counter)
	    {
		mpi_errno = MPID_Progress_wait(&progress_state);
		/* --BEGIN ERROR HANDLING-- */
		if (mpi_errno != MPI_SUCCESS) {
		    MPID_Progress_end(&progress_state);
		    MPIU_ERR_SETANDJUMP(mpi_errno,MPI_ERR_OTHER,"**winnoprogress");
		}
		/* --END ERROR HANDLING-- */
		MPIU_INSTR_DURATION_INCR(winfence_wait,0,1);
	    }
	    MPID_Progress_end(&progress_state);
	    MPIU_INSTR_DURATION_END(winfence_wait);
	} 
	
	if (assert & MPI_MODE_NOSUCCEED)
	{
	    win_ptr->fence_issued = 0;
	}

        win_ptr->epoch_state = MPIDI_EPOCH_NONE;
    }

 fn_exit:
    MPIU_CHKLMEM_FREEALL();
    MPIDI_RMA_FUNC_EXIT(MPID_STATE_MPIDI_WIN_FENCE);
    return mpi_errno;
    /* --BEGIN ERROR HANDLING-- */
 fn_fail:
    goto fn_exit;
    /* --END ERROR HANDLING-- */
}

/* create_datatype() creates a new struct datatype for the dtype_info
   and the dataloop of the target datatype together with the user data */
#undef FUNCNAME
#define FUNCNAME create_datatype
#undef FCNAME
#define FCNAME MPIDI_QUOTE(FUNCNAME)
static int create_datatype(const MPIDI_RMA_dtype_info *dtype_info,
                           const void *dataloop, MPI_Aint dataloop_sz,
                           const void *o_addr, int o_count, MPI_Datatype o_datatype,
                           MPID_Datatype **combined_dtp)
{
    int mpi_errno = MPI_SUCCESS;
    /* datatype_set_contents wants an array 'ints' which is the
       blocklens array with count prepended to it.  So blocklens
       points to the 2nd element of ints to avoid having to copy
       blocklens into ints later. */
    int ints[4];
    int *blocklens = &ints[1];
    MPI_Aint displaces[3];
    MPI_Datatype datatypes[3];
    const int count = 3;
    MPI_Datatype combined_datatype;
    MPIDI_STATE_DECL(MPID_STATE_CREATE_DATATYPE);

    MPIDI_FUNC_ENTER(MPID_STATE_CREATE_DATATYPE);

    /* create datatype */
    displaces[0] = MPIU_PtrToAint(dtype_info);
    blocklens[0] = sizeof(*dtype_info);
    datatypes[0] = MPI_BYTE;
    
    displaces[1] = MPIU_PtrToAint(dataloop);
    blocklens[1] = dataloop_sz;
    datatypes[1] = MPI_BYTE;
    
    displaces[2] = MPIU_PtrToAint(o_addr);
    blocklens[2] = o_count;
    datatypes[2] = o_datatype;
    
    mpi_errno = MPID_Type_struct(count,
                                 blocklens,
                                 displaces,
                                 datatypes,
                                 &combined_datatype);
    if (mpi_errno) MPIU_ERR_POP(mpi_errno);
   
    ints[0] = count;

    MPID_Datatype_get_ptr(combined_datatype, *combined_dtp);    
    mpi_errno = MPID_Datatype_set_contents(*combined_dtp,
				           MPI_COMBINER_STRUCT,
				           count+1, /* ints (cnt,blklen) */
				           count, /* aints (disps) */
				           count, /* types */
				           ints,
				           displaces,
				           datatypes);
    if (mpi_errno) MPIU_ERR_POP(mpi_errno);

    /* Commit datatype */
    
    MPID_Dataloop_create(combined_datatype,
                         &(*combined_dtp)->dataloop,
                         &(*combined_dtp)->dataloop_size,
                         &(*combined_dtp)->dataloop_depth,
                         MPID_DATALOOP_HOMOGENEOUS);
    
    /* create heterogeneous dataloop */
    MPID_Dataloop_create(combined_datatype,
                         &(*combined_dtp)->hetero_dloop,
                         &(*combined_dtp)->hetero_dloop_size,
                         &(*combined_dtp)->hetero_dloop_depth,
                         MPID_DATALOOP_HETEROGENEOUS);
 
 fn_exit:
    MPIDI_FUNC_EXIT(MPID_STATE_CREATE_DATATYPE);
    return mpi_errno;
 fn_fail:
    goto fn_exit;
}


#undef FUNCNAME
#define FUNCNAME MPIDI_CH3I_Send_rma_msg
#undef FCNAME
#define FCNAME MPIDI_QUOTE(FUNCNAME)
static int MPIDI_CH3I_Send_rma_msg(MPIDI_RMA_Op_t *rma_op, MPID_Win *win_ptr,
				   MPI_Win source_win_handle, 
				   MPI_Win target_win_handle, 
				   MPIDI_RMA_dtype_info *dtype_info, 
				   void **dataloop, MPID_Request **request) 
{
    MPIDI_CH3_Pkt_t upkt;
    MPIDI_CH3_Pkt_put_t *put_pkt = &upkt.put;
    MPIDI_CH3_Pkt_accum_t *accum_pkt = &upkt.accum;
    MPID_IOV iov[MPID_IOV_LIMIT];
    int mpi_errno=MPI_SUCCESS, predefined;
    int origin_dt_derived, target_dt_derived, origin_type_size, iovcnt; 
    MPIDI_VC_t * vc;
    MPID_Comm *comm_ptr;
    MPID_Datatype *target_dtp=NULL, *origin_dtp=NULL;
    MPID_Request *resp_req=NULL;
    MPIU_CHKPMEM_DECL(1);
    MPIDI_STATE_DECL(MPID_STATE_MPIDI_CH3I_SEND_RMA_MSG);
    MPIDI_STATE_DECL(MPID_STATE_MEMCPY);

    MPIDI_RMA_FUNC_ENTER(MPID_STATE_MPIDI_CH3I_SEND_RMA_MSG);

    *request = NULL;

    if (rma_op->type == MPIDI_RMA_PUT)
    {
        MPIDI_Pkt_init(put_pkt, MPIDI_CH3_PKT_PUT);
        put_pkt->addr = (char *) win_ptr->base_addrs[rma_op->target_rank] +
            win_ptr->disp_units[rma_op->target_rank] * rma_op->target_disp;

        put_pkt->count = rma_op->target_count;
        put_pkt->datatype = rma_op->target_datatype;
        put_pkt->dataloop_size = 0;
        put_pkt->target_win_handle = target_win_handle;
        put_pkt->source_win_handle = source_win_handle;
        
        iov[0].MPID_IOV_BUF = (MPID_IOV_BUF_CAST) put_pkt;
        iov[0].MPID_IOV_LEN = sizeof(*put_pkt);
    }
    else if (rma_op->type == MPIDI_RMA_GET_ACCUMULATE)
    {
        /* Create a request for the GACC response.  Store the response buf, count, and
           datatype in it, and pass the request's handle in the GACC packet. When the
           response comes from the target, it will contain the request handle. */
        resp_req = MPID_Request_create();
        MPIU_ERR_CHKANDJUMP(resp_req == NULL, mpi_errno, MPI_ERR_OTHER, "**nomemreq");

        MPIU_Object_set_ref(resp_req, 2);

        resp_req->dev.user_buf = rma_op->result_addr;
        resp_req->dev.user_count = rma_op->result_count;
        resp_req->dev.datatype = rma_op->result_datatype;
        resp_req->dev.target_win_handle = target_win_handle;
        resp_req->dev.source_win_handle = source_win_handle;

        MPIDI_CH3I_DATATYPE_IS_PREDEFINED(resp_req->dev.datatype, predefined);
        if (!predefined) {
            MPID_Datatype *result_dtp = NULL;
            MPID_Datatype_get_ptr(resp_req->dev.datatype, result_dtp);
            resp_req->dev.datatype_ptr = result_dtp;
            /* this will cause the datatype to be freed when the
               request is freed. */
        }

        /* Note: Get_accumulate uses the same packet type as accumulate */
        MPIDI_Pkt_init(accum_pkt, MPIDI_CH3_PKT_GET_ACCUM);
        accum_pkt->addr = (char *) win_ptr->base_addrs[rma_op->target_rank] +
            win_ptr->disp_units[rma_op->target_rank] * rma_op->target_disp;
        accum_pkt->count = rma_op->target_count;
        accum_pkt->datatype = rma_op->target_datatype;
        accum_pkt->dataloop_size = 0;
        accum_pkt->op = rma_op->op;
        accum_pkt->target_win_handle = target_win_handle;
        accum_pkt->source_win_handle = source_win_handle;
        accum_pkt->request_handle = resp_req->handle;

        iov[0].MPID_IOV_BUF = (MPID_IOV_BUF_CAST) accum_pkt;
        iov[0].MPID_IOV_LEN = sizeof(*accum_pkt);
    }
    else
    {
        MPIDI_Pkt_init(accum_pkt, MPIDI_CH3_PKT_ACCUMULATE);
        accum_pkt->addr = (char *) win_ptr->base_addrs[rma_op->target_rank] +
            win_ptr->disp_units[rma_op->target_rank] * rma_op->target_disp;
        accum_pkt->count = rma_op->target_count;
        accum_pkt->datatype = rma_op->target_datatype;
        accum_pkt->dataloop_size = 0;
        accum_pkt->op = rma_op->op;
        accum_pkt->target_win_handle = target_win_handle;
        accum_pkt->source_win_handle = source_win_handle;

        iov[0].MPID_IOV_BUF = (MPID_IOV_BUF_CAST) accum_pkt;
        iov[0].MPID_IOV_LEN = sizeof(*accum_pkt);
    }

    /*    printf("send pkt: type %d, addr %d, count %d, base %d\n", rma_pkt->type,
          rma_pkt->addr, rma_pkt->count, win_ptr->base_addrs[rma_op->target_rank]);
          fflush(stdout);
    */

    comm_ptr = win_ptr->comm_ptr;
    MPIDI_Comm_get_vc_set_active(comm_ptr, rma_op->target_rank, &vc);

    MPIDI_CH3I_DATATYPE_IS_PREDEFINED(rma_op->origin_datatype, predefined);
    if (!predefined)
    {
        origin_dt_derived = 1;
        MPID_Datatype_get_ptr(rma_op->origin_datatype, origin_dtp);
    }
    else
    {
        origin_dt_derived = 0;
    }

    MPIDI_CH3I_DATATYPE_IS_PREDEFINED(rma_op->target_datatype, predefined);
    if (!predefined)
    {
        target_dt_derived = 1;
        MPID_Datatype_get_ptr(rma_op->target_datatype, target_dtp);
    }
    else
    {
        target_dt_derived = 0;
    }

    if (target_dt_derived)
    {
        /* derived datatype on target. fill derived datatype info */
        dtype_info->is_contig = target_dtp->is_contig;
        dtype_info->max_contig_blocks = target_dtp->max_contig_blocks;
        dtype_info->size = target_dtp->size;
        dtype_info->extent = target_dtp->extent;
        dtype_info->dataloop_size = target_dtp->dataloop_size;
        dtype_info->dataloop_depth = target_dtp->dataloop_depth;
        dtype_info->eltype = target_dtp->eltype;
        dtype_info->dataloop = target_dtp->dataloop;
        dtype_info->ub = target_dtp->ub;
        dtype_info->lb = target_dtp->lb;
        dtype_info->true_ub = target_dtp->true_ub;
        dtype_info->true_lb = target_dtp->true_lb;
        dtype_info->has_sticky_ub = target_dtp->has_sticky_ub;
        dtype_info->has_sticky_lb = target_dtp->has_sticky_lb;

	MPIU_CHKPMEM_MALLOC(*dataloop, void *, target_dtp->dataloop_size, 
			    mpi_errno, "dataloop");

	MPIDI_FUNC_ENTER(MPID_STATE_MEMCPY);
        MPIU_Memcpy(*dataloop, target_dtp->dataloop, target_dtp->dataloop_size);
	MPIDI_FUNC_EXIT(MPID_STATE_MEMCPY);
        /* the dataloop can have undefined padding sections, so we need to let
         * valgrind know that it is OK to pass this data to writev later on */
        MPL_VG_MAKE_MEM_DEFINED(*dataloop, target_dtp->dataloop_size);

        if (rma_op->type == MPIDI_RMA_PUT)
	{
            put_pkt->dataloop_size = target_dtp->dataloop_size;
	}
        else
	{
            accum_pkt->dataloop_size = target_dtp->dataloop_size;
	}
    }

    MPID_Datatype_get_size_macro(rma_op->origin_datatype, origin_type_size);

    if (!target_dt_derived)
    {
        /* basic datatype on target */
        if (!origin_dt_derived)
        {
            /* basic datatype on origin */
            iov[1].MPID_IOV_BUF = (MPID_IOV_BUF_CAST)rma_op->origin_addr;
            iov[1].MPID_IOV_LEN = rma_op->origin_count * origin_type_size;
            iovcnt = 2;
	    MPIU_THREAD_CS_ENTER(CH3COMM,vc);
            mpi_errno = MPIDI_CH3_iStartMsgv(vc, iov, iovcnt, request);
	    MPIU_THREAD_CS_EXIT(CH3COMM,vc);
            MPIU_ERR_CHKANDJUMP(mpi_errno, mpi_errno, MPI_ERR_OTHER, "**ch3|rmamsg");
        }
        else
        {
            /* derived datatype on origin */
            *request = MPID_Request_create();
            MPIU_ERR_CHKANDJUMP(*request == NULL,mpi_errno,MPI_ERR_OTHER,"**nomemreq");
            
            MPIU_Object_set_ref(*request, 2);
            (*request)->kind = MPID_REQUEST_SEND;
            
            (*request)->dev.segment_ptr = MPID_Segment_alloc( );
            MPIU_ERR_CHKANDJUMP1((*request)->dev.segment_ptr == NULL, mpi_errno, MPI_ERR_OTHER, "**nomem", "**nomem %s", "MPID_Segment_alloc");

            (*request)->dev.datatype_ptr = origin_dtp;
            /* this will cause the datatype to be freed when the request
               is freed. */
            MPID_Segment_init(rma_op->origin_addr, rma_op->origin_count,
                              rma_op->origin_datatype,
                              (*request)->dev.segment_ptr, 0);
            (*request)->dev.segment_first = 0;
            (*request)->dev.segment_size = rma_op->origin_count * origin_type_size;

            (*request)->dev.OnFinal = 0;
            (*request)->dev.OnDataAvail = 0;

	    MPIU_THREAD_CS_ENTER(CH3COMM,vc);
            mpi_errno = vc->sendNoncontig_fn(vc, *request, iov[0].MPID_IOV_BUF, iov[0].MPID_IOV_LEN);
	    MPIU_THREAD_CS_EXIT(CH3COMM,vc);
            MPIU_ERR_CHKANDJUMP(mpi_errno, mpi_errno, MPI_ERR_OTHER, "**ch3|rmamsg");
        }
    }
    else
    {
        /* derived datatype on target */
        MPID_Datatype *combined_dtp = NULL;

        *request = MPID_Request_create();
        if (*request == NULL) {
	    MPIU_ERR_SETANDJUMP(mpi_errno,MPI_ERR_OTHER,"**nomemreq");
        }

        MPIU_Object_set_ref(*request, 2);
        (*request)->kind = MPID_REQUEST_SEND;

	(*request)->dev.segment_ptr = MPID_Segment_alloc( );
        MPIU_ERR_CHKANDJUMP1((*request)->dev.segment_ptr == NULL, mpi_errno, MPI_ERR_OTHER, "**nomem", "**nomem %s", "MPID_Segment_alloc");

        /* create a new datatype containing the dtype_info, dataloop, and origin data */

        mpi_errno = create_datatype(dtype_info, *dataloop, target_dtp->dataloop_size, rma_op->origin_addr,
                                    rma_op->origin_count, rma_op->origin_datatype, &combined_dtp);
        if (mpi_errno) MPIU_ERR_POP(mpi_errno);

        (*request)->dev.datatype_ptr = combined_dtp;
        /* combined_datatype will be freed when request is freed */

        MPID_Segment_init(MPI_BOTTOM, 1, combined_dtp->handle,
                          (*request)->dev.segment_ptr, 0);
        (*request)->dev.segment_first = 0;
        (*request)->dev.segment_size = combined_dtp->size;

        (*request)->dev.OnFinal = 0;
        (*request)->dev.OnDataAvail = 0;

	MPIU_THREAD_CS_ENTER(CH3COMM,vc);
        mpi_errno = vc->sendNoncontig_fn(vc, *request, iov[0].MPID_IOV_BUF, iov[0].MPID_IOV_LEN);
	MPIU_THREAD_CS_EXIT(CH3COMM,vc);
        MPIU_ERR_CHKANDJUMP(mpi_errno, mpi_errno, MPI_ERR_OTHER, "**ch3|rmamsg");

        /* we're done with the datatypes */
        if (origin_dt_derived)
            MPID_Datatype_release(origin_dtp);
        MPID_Datatype_release(target_dtp);
    }

    /* This operation can generate two requests; one for inbound and one for
       outbound data. */
    if (resp_req != NULL) {
        if (*request != NULL) {
            /* If we have both inbound and outbound requests (i.e. GACC
               operation), we need to ensure that the source buffer is
               available and that the response data has been received before
               informing the origin that this operation is complete.  Because
               the update needs to be done atomically at the target, they will
               not send back data until it has been received.  Therefore,
               completion of the response request implies that the send request
               has completed.

               Therefore: refs on the response request are set to two: one is
               held by the progress engine and the other by the RMA op
               completion code.  Refs on the outbound request are set to one;
               it will be completed by the progress engine.
             */

            MPID_Request_release(*request);
            *request = resp_req;

        } else {
            *request = resp_req;
        }

        /* For error checking */
        resp_req = NULL;
    }

 fn_exit:
    MPIU_CHKPMEM_COMMIT();
    MPIDI_RMA_FUNC_EXIT(MPID_STATE_MPIDI_CH3I_SEND_RMA_MSG);
    return mpi_errno;
    /* --BEGIN ERROR HANDLING-- */
 fn_fail:
    if (resp_req) {
        MPIU_Object_set_ref(resp_req, 0);
        MPIDI_CH3_Request_destroy(resp_req);
    }
    if (*request)
    {
        MPIU_CHKPMEM_REAP();
        if ((*request)->dev.datatype_ptr)
            MPID_Datatype_release((*request)->dev.datatype_ptr);
        MPIU_Object_set_ref(*request, 0);
        MPIDI_CH3_Request_destroy(*request);
    }
    *request = NULL;
    goto fn_exit;
    /* --END ERROR HANDLING-- */
}

/*
 * Use this for contiguous accumulate operations
 */
#undef FUNCNAME
#define FUNCNAME MPIDI_CH3I_Send_contig_acc_msg
#undef FCNAME
#define FCNAME MPIDI_QUOTE(FUNCNAME)
static int MPIDI_CH3I_Send_contig_acc_msg(MPIDI_RMA_Op_t *rma_op,
					  MPID_Win *win_ptr,
					  MPI_Win source_win_handle, 
					  MPI_Win target_win_handle, 
					  MPID_Request **request) 
{
    MPIDI_CH3_Pkt_t upkt;
    MPIDI_CH3_Pkt_accum_t *accum_pkt = &upkt.accum;
    MPID_IOV iov[MPID_IOV_LIMIT];
    int mpi_errno=MPI_SUCCESS;
    int origin_type_size, iovcnt; 
    MPIDI_VC_t * vc;
    MPID_Comm *comm_ptr;
    int len;
    MPIDI_STATE_DECL(MPID_STATE_MPIDI_CH3I_SEND_CONTIG_ACC_MSG);

    MPIDI_RMA_FUNC_ENTER(MPID_STATE_MPIDI_CH3I_SEND_CONTIG_ACC_MSG);

    *request = NULL;

    MPID_Datatype_get_size_macro(rma_op->origin_datatype, origin_type_size);
    /* FIXME: Make this size check efficient and match the packet type */
    len = rma_op->origin_count * origin_type_size;
    if (MPIR_PARAM_RMA_ACC_IMMED && len <= MPIDI_RMA_IMMED_INTS*sizeof(int)) {
	MPIDI_CH3_Pkt_accum_immed_t * accumi_pkt = &upkt.accum_immed;
	void *dest = accumi_pkt->data, *src = rma_op->origin_addr;
	
	MPIDI_Pkt_init(accumi_pkt, MPIDI_CH3_PKT_ACCUM_IMMED);
	accumi_pkt->addr = (char *) win_ptr->base_addrs[rma_op->target_rank] +
	    win_ptr->disp_units[rma_op->target_rank] * rma_op->target_disp;
	accumi_pkt->count = rma_op->target_count;
	accumi_pkt->datatype = rma_op->target_datatype;
	accumi_pkt->op = rma_op->op;
	accumi_pkt->target_win_handle = target_win_handle;
	accumi_pkt->source_win_handle = source_win_handle;
	
	switch (len) {
	case 1: *(uint8_t *)dest  = *(uint8_t *)src;  break;
	case 2: *(uint16_t *)dest = *(uint16_t *)src; break;
	case 4: *(uint32_t *)dest = *(uint32_t *)src; break;
	case 8: *(uint64_t *)dest = *(uint64_t *)src; break;
	default:
	    MPIU_Memcpy( accumi_pkt->data, (void *)rma_op->origin_addr, len );
	}
	comm_ptr = win_ptr->comm_ptr;
	MPIDI_Comm_get_vc_set_active(comm_ptr, rma_op->target_rank, &vc);
	MPIU_THREAD_CS_ENTER(CH3COMM,vc);
	mpi_errno = MPIDI_CH3_iStartMsg(vc, accumi_pkt, sizeof(*accumi_pkt), request);
	MPIU_THREAD_CS_EXIT(CH3COMM,vc);
	MPIU_ERR_CHKANDJUMP(mpi_errno, mpi_errno, MPI_ERR_OTHER, "**ch3|rmamsg");
	goto fn_exit;
    }

    MPIDI_Pkt_init(accum_pkt, MPIDI_CH3_PKT_ACCUMULATE);
    accum_pkt->addr = (char *) win_ptr->base_addrs[rma_op->target_rank] +
	win_ptr->disp_units[rma_op->target_rank] * rma_op->target_disp;
    accum_pkt->count = rma_op->target_count;
    accum_pkt->datatype = rma_op->target_datatype;
    accum_pkt->dataloop_size = 0;
    accum_pkt->op = rma_op->op;
    accum_pkt->target_win_handle = target_win_handle;
    accum_pkt->source_win_handle = source_win_handle;
    
    iov[0].MPID_IOV_BUF = (MPID_IOV_BUF_CAST) accum_pkt;
    iov[0].MPID_IOV_LEN = sizeof(*accum_pkt);

    /*    printf("send pkt: type %d, addr %d, count %d, base %d\n", rma_pkt->type,
          rma_pkt->addr, rma_pkt->count, win_ptr->base_addrs[rma_op->target_rank]);
          fflush(stdout);
    */

    comm_ptr = win_ptr->comm_ptr;
    MPIDI_Comm_get_vc_set_active(comm_ptr, rma_op->target_rank, &vc);


    /* basic datatype on target */
    /* basic datatype on origin */
    /* FIXME: This is still very heavyweight for a small message operation,
       such as a single word update */
    /* One possibility is to use iStartMsg with a buffer that is just large 
       enough, though note that nemesis has an optimization for this */
    iov[1].MPID_IOV_BUF = (MPID_IOV_BUF_CAST)rma_op->origin_addr;
    iov[1].MPID_IOV_LEN = rma_op->origin_count * origin_type_size;
    iovcnt = 2;
    MPIU_THREAD_CS_ENTER(CH3COMM,vc);
    mpi_errno = MPIDI_CH3_iStartMsgv(vc, iov, iovcnt, request);
    MPIU_THREAD_CS_EXIT(CH3COMM,vc);
    MPIU_ERR_CHKANDJUMP(mpi_errno, mpi_errno, MPI_ERR_OTHER, "**ch3|rmamsg");

 fn_exit:
    MPIDI_RMA_FUNC_EXIT(MPID_STATE_MPIDI_CH3I_SEND_CONTIG_ACC_MSG);
    return mpi_errno;
    /* --BEGIN ERROR HANDLING-- */
 fn_fail:
    if (*request)
    {
        MPIU_Object_set_ref(*request, 0);
        MPIDI_CH3_Request_destroy(*request);
    }
    *request = NULL;
    goto fn_exit;
    /* --END ERROR HANDLING-- */
}


/*
 * Initiate an immediate RMW accumulate operation
 */
#undef FUNCNAME
#define FUNCNAME MPIDI_CH3I_Send_immed_rmw_msg
#undef FCNAME
#define FCNAME MPIDI_QUOTE(FUNCNAME)
static int MPIDI_CH3I_Send_immed_rmw_msg(MPIDI_RMA_Op_t *rma_op,
                                         MPID_Win *win_ptr,
                                         MPI_Win source_win_handle, 
                                         MPI_Win target_win_handle, 
                                         MPID_Request **request) 
{
    int mpi_errno = MPI_SUCCESS;
    MPID_Request *rmw_req = NULL, *resp_req = NULL;
    MPIDI_VC_t *vc;
    MPID_Comm *comm_ptr;
    int len;
    MPIDI_STATE_DECL(MPID_STATE_MPIDI_CH3I_SEND_IMMED_RMW_MSG);

    MPIDI_RMA_FUNC_ENTER(MPID_STATE_MPIDI_CH3I_SEND_IMMED_RMW_MSG);

    *request = NULL;

    /* Create a request for the RMW response.  Store the origin buf, count, and
       datatype in it, and pass the request's handle RMW packet. When the
       response comes from the target, it will contain the request handle. */
    resp_req = MPID_Request_create();
    MPIU_ERR_CHKANDJUMP(resp_req == NULL, mpi_errno, MPI_ERR_OTHER, "**nomemreq");
    *request = resp_req;

    /* Set refs on the request to 2: one for the response message, and one for
       the partial completion handler */
    MPIU_Object_set_ref(resp_req, 2);

    resp_req->dev.user_buf = rma_op->result_addr;
    resp_req->dev.user_count = rma_op->result_count;
    resp_req->dev.datatype = rma_op->result_datatype;
    resp_req->dev.target_win_handle = target_win_handle;
    resp_req->dev.source_win_handle = source_win_handle;

    /* REQUIRE: All datatype arguments must be of the same, builtin
                type and counts must be 1. */
    MPID_Datatype_get_size_macro(rma_op->origin_datatype, len);
    comm_ptr = win_ptr->comm_ptr;

    if (rma_op->type == MPIDI_RMA_COMPARE_AND_SWAP) {
        MPIDI_CH3_Pkt_t upkt;
        MPIDI_CH3_Pkt_cas_t *cas_pkt = &upkt.cas;

        MPIU_Assert(len <= sizeof(MPIDI_CH3_CAS_Immed_u));

        /* If this is the last operation, it also unlocks the window 
           at the target. */
        if (source_win_handle != MPI_WIN_NULL) {
            MPIDI_Pkt_init(cas_pkt, MPIDI_CH3_PKT_CAS_UNLOCK);
        } else {
            MPIDI_Pkt_init(cas_pkt, MPIDI_CH3_PKT_CAS);
        }

        cas_pkt->addr = (char *) win_ptr->base_addrs[rma_op->target_rank] +
            win_ptr->disp_units[rma_op->target_rank] * rma_op->target_disp;
        cas_pkt->datatype = rma_op->target_datatype;
        cas_pkt->target_win_handle = target_win_handle;
        cas_pkt->request_handle = resp_req->handle;

        MPIU_Memcpy( (void *) &cas_pkt->origin_data, rma_op->origin_addr, len );
        MPIU_Memcpy( (void *) &cas_pkt->compare_data, rma_op->compare_addr, len );

        MPIDI_Comm_get_vc_set_active(comm_ptr, rma_op->target_rank, &vc);
        MPIU_THREAD_CS_ENTER(CH3COMM,vc);
        mpi_errno = MPIDI_CH3_iStartMsg(vc, cas_pkt, sizeof(*cas_pkt), &rmw_req);
        MPIU_THREAD_CS_EXIT(CH3COMM,vc);
        MPIU_ERR_CHKANDJUMP(mpi_errno, mpi_errno, MPI_ERR_OTHER, "**ch3|rmamsg");

        if (rmw_req != NULL) {
            MPID_Request_release(rmw_req);
        }
    }

    else if (rma_op->type == MPIDI_RMA_FETCH_AND_OP) {
        MPIDI_CH3_Pkt_t upkt;
        MPIDI_CH3_Pkt_fop_t *fop_pkt = &upkt.fop;

        MPIU_Assert(len <= sizeof(MPIDI_CH3_FOP_Immed_u));

        MPIDI_Pkt_init(fop_pkt, MPIDI_CH3_PKT_FOP);

        fop_pkt->addr = (char *) win_ptr->base_addrs[rma_op->target_rank] +
            win_ptr->disp_units[rma_op->target_rank] * rma_op->target_disp;
        fop_pkt->datatype = rma_op->target_datatype;
        fop_pkt->target_win_handle = target_win_handle;
        fop_pkt->source_win_handle = source_win_handle;
        fop_pkt->request_handle = resp_req->handle;
        fop_pkt->op = rma_op->op;

        if (len <= sizeof(fop_pkt->origin_data) || rma_op->op == MPI_NO_OP) {
            /* Embed FOP data in the packet header */
            if (rma_op->op != MPI_NO_OP) {
                MPIU_Memcpy( fop_pkt->origin_data, rma_op->origin_addr, len );
            }

            MPIDI_Comm_get_vc_set_active(comm_ptr, rma_op->target_rank, &vc);
            MPIU_THREAD_CS_ENTER(CH3COMM,vc);
            mpi_errno = MPIDI_CH3_iStartMsg(vc, fop_pkt, sizeof(*fop_pkt), &rmw_req);
            MPIU_THREAD_CS_EXIT(CH3COMM,vc);
            MPIU_ERR_CHKANDJUMP(mpi_errno, mpi_errno, MPI_ERR_OTHER, "**ch3|rmamsg");

            if (rmw_req != NULL) {
                MPID_Request_release(rmw_req);
            }
        }
        else {
            /* Data is too big to copy into the FOP header, use an IOV to send it */
            MPID_IOV iov[MPID_IOV_LIMIT];

            rmw_req = MPID_Request_create();
            MPIU_ERR_CHKANDJUMP(rmw_req == NULL, mpi_errno, MPI_ERR_OTHER, "**nomemreq");
            MPIU_Object_set_ref(rmw_req, 1);

            rmw_req->dev.OnFinal = 0;
            rmw_req->dev.OnDataAvail = 0;

            iov[0].MPID_IOV_BUF = (MPID_IOV_BUF_CAST)fop_pkt;
            iov[0].MPID_IOV_LEN = sizeof(*fop_pkt);
            iov[1].MPID_IOV_BUF = (MPID_IOV_BUF_CAST)rma_op->origin_addr;
            iov[1].MPID_IOV_LEN = len; /* count == 1 */

            MPIDI_Comm_get_vc_set_active(comm_ptr, rma_op->target_rank, &vc);
            MPIU_THREAD_CS_ENTER(CH3COMM,vc);
            mpi_errno = MPIDI_CH3_iSendv(vc, rmw_req, iov, 2);
            MPIU_THREAD_CS_EXIT(CH3COMM,vc);

            MPIU_ERR_CHKANDJUMP(mpi_errno != MPI_SUCCESS, mpi_errno, MPI_ERR_OTHER, "**ch3|rmamsg");
        }
    }
    else {
        MPIU_ERR_SETANDJUMP(mpi_errno, MPI_ERR_OTHER, "**ch3|rmamsg");
    }

fn_exit:
    MPIDI_RMA_FUNC_EXIT(MPID_STATE_MPIDI_CH3I_SEND_IMMED_RMW_MSG);
    return mpi_errno;
    /* --BEGIN ERROR HANDLING-- */
fn_fail:
    if (*request) {
        MPIU_Object_set_ref(*request, 0);
        MPIDI_CH3_Request_destroy(*request);
    }
    *request = NULL;
    if (rmw_req) {
        MPIU_Object_set_ref(rmw_req, 0);
        MPIDI_CH3_Request_destroy(rmw_req);
    }
    goto fn_exit;
    /* --END ERROR HANDLING-- */
}



#undef FUNCNAME
#define FUNCNAME MPIDI_CH3I_Recv_rma_msg
#undef FCNAME
#define FCNAME MPIDI_QUOTE(FUNCNAME)
static int MPIDI_CH3I_Recv_rma_msg(MPIDI_RMA_Op_t *rma_op, MPID_Win *win_ptr,
				   MPI_Win source_win_handle, 
				   MPI_Win target_win_handle, 
				   MPIDI_RMA_dtype_info *dtype_info, 
				   void **dataloop, MPID_Request **request) 
{
    MPIDI_CH3_Pkt_t upkt;
    MPIDI_CH3_Pkt_get_t *get_pkt = &upkt.get;
    int mpi_errno=MPI_SUCCESS, predefined;
    MPIDI_VC_t * vc;
    MPID_Comm *comm_ptr;
    MPID_Request *req = NULL;
    MPID_Datatype *dtp;
    MPID_IOV iov[MPID_IOV_LIMIT];
    MPIU_CHKPMEM_DECL(1);
    MPIDI_STATE_DECL(MPID_STATE_MPIDI_CH3I_RECV_RMA_MSG);
    MPIDI_STATE_DECL(MPID_STATE_MEMCPY);

    MPIDI_RMA_FUNC_ENTER(MPID_STATE_MPIDI_CH3I_RECV_RMA_MSG);

    /* create a request, store the origin buf, cnt, datatype in it,
       and pass a handle to it in the get packet. When the get
       response comes from the target, it will contain the request
       handle. */  
    req = MPID_Request_create();
    if (req == NULL) {
	MPIU_ERR_SETANDJUMP(mpi_errno,MPI_ERR_OTHER,"**nomemreq");
    }

    *request = req;

    MPIU_Object_set_ref(req, 2);

    req->dev.user_buf = rma_op->origin_addr;
    req->dev.user_count = rma_op->origin_count;
    req->dev.datatype = rma_op->origin_datatype;
    req->dev.target_win_handle = MPI_WIN_NULL;
    req->dev.source_win_handle = source_win_handle;
    MPIDI_CH3I_DATATYPE_IS_PREDEFINED(req->dev.datatype, predefined);
    if (!predefined)
    {
        MPID_Datatype_get_ptr(req->dev.datatype, dtp);
        req->dev.datatype_ptr = dtp;
        /* this will cause the datatype to be freed when the
           request is freed. */  
    }

    MPIDI_Pkt_init(get_pkt, MPIDI_CH3_PKT_GET);
    get_pkt->addr = (char *) win_ptr->base_addrs[rma_op->target_rank] +
        win_ptr->disp_units[rma_op->target_rank] * rma_op->target_disp;
    get_pkt->count = rma_op->target_count;
    get_pkt->datatype = rma_op->target_datatype;
    get_pkt->request_handle = req->handle;
    get_pkt->target_win_handle = target_win_handle;
    get_pkt->source_win_handle = source_win_handle;

/*    printf("send pkt: type %d, addr %d, count %d, base %d\n", rma_pkt->type,
           rma_pkt->addr, rma_pkt->count, win_ptr->base_addrs[rma_op->target_rank]);
    fflush(stdout);
*/
	    
    comm_ptr = win_ptr->comm_ptr;
    MPIDI_Comm_get_vc_set_active(comm_ptr, rma_op->target_rank, &vc);

    MPIDI_CH3I_DATATYPE_IS_PREDEFINED(rma_op->target_datatype, predefined);
    if (predefined)
    {
        /* basic datatype on target. simply send the get_pkt. */
	MPIU_THREAD_CS_ENTER(CH3COMM,vc);
        mpi_errno = MPIDI_CH3_iStartMsg(vc, get_pkt, sizeof(*get_pkt), &req);
	MPIU_THREAD_CS_EXIT(CH3COMM,vc);
    }
    else
    {
        /* derived datatype on target. fill derived datatype info and
           send it along with get_pkt. */

        MPID_Datatype_get_ptr(rma_op->target_datatype, dtp);
        dtype_info->is_contig = dtp->is_contig;
        dtype_info->max_contig_blocks = dtp->max_contig_blocks;
        dtype_info->size = dtp->size;
        dtype_info->extent = dtp->extent;
        dtype_info->dataloop_size = dtp->dataloop_size;
        dtype_info->dataloop_depth = dtp->dataloop_depth;
        dtype_info->eltype = dtp->eltype;
        dtype_info->dataloop = dtp->dataloop;
        dtype_info->ub = dtp->ub;
        dtype_info->lb = dtp->lb;
        dtype_info->true_ub = dtp->true_ub;
        dtype_info->true_lb = dtp->true_lb;
        dtype_info->has_sticky_ub = dtp->has_sticky_ub;
        dtype_info->has_sticky_lb = dtp->has_sticky_lb;

	MPIU_CHKPMEM_MALLOC(*dataloop, void *, dtp->dataloop_size, 
			    mpi_errno, "dataloop");

	MPIDI_FUNC_ENTER(MPID_STATE_MEMCPY);
        MPIU_Memcpy(*dataloop, dtp->dataloop, dtp->dataloop_size);
	MPIDI_FUNC_EXIT(MPID_STATE_MEMCPY);

        /* the dataloop can have undefined padding sections, so we need to let
         * valgrind know that it is OK to pass this data to writev later on */
        MPL_VG_MAKE_MEM_DEFINED(*dataloop, dtp->dataloop_size);

        get_pkt->dataloop_size = dtp->dataloop_size;

        iov[0].MPID_IOV_BUF = (MPID_IOV_BUF_CAST)get_pkt;
        iov[0].MPID_IOV_LEN = sizeof(*get_pkt);
        iov[1].MPID_IOV_BUF = (MPID_IOV_BUF_CAST)dtype_info;
        iov[1].MPID_IOV_LEN = sizeof(*dtype_info);
        iov[2].MPID_IOV_BUF = (MPID_IOV_BUF_CAST)*dataloop;
        iov[2].MPID_IOV_LEN = dtp->dataloop_size;

	MPIU_THREAD_CS_ENTER(CH3COMM,vc);
        mpi_errno = MPIDI_CH3_iStartMsgv(vc, iov, 3, &req);
	MPIU_THREAD_CS_EXIT(CH3COMM,vc);

        /* release the target datatype */
        MPID_Datatype_release(dtp);
    }

    if (mpi_errno != MPI_SUCCESS) {
	MPIU_ERR_SETANDJUMP(mpi_errno,MPI_ERR_OTHER,"**ch3|rmamsg");
    }

    /* release the request returned by iStartMsg or iStartMsgv */
    if (req != NULL)
    {
        MPID_Request_release(req);
    }

 fn_exit:
    MPIDI_RMA_FUNC_EXIT(MPID_STATE_MPIDI_CH3I_RECV_RMA_MSG);
    return mpi_errno;

    /* --BEGIN ERROR HANDLING-- */
 fn_fail:
    MPIU_CHKPMEM_REAP();
    goto fn_exit;
    /* --END ERROR HANDLING-- */
}


#undef FUNCNAME
#define FUNCNAME MPIDI_Win_post
#undef FCNAME
#define FCNAME MPIDI_QUOTE(FUNCNAME)
int MPIDI_Win_post(MPID_Group *post_grp_ptr, int assert, MPID_Win *win_ptr)
{
    int mpi_errno=MPI_SUCCESS;
    MPID_Group *win_grp_ptr;
    int i, post_grp_size, *ranks_in_post_grp, *ranks_in_win_grp, dst, rank;
    MPID_Comm *win_comm_ptr;
    MPIU_CHKLMEM_DECL(4);
    MPIDI_STATE_DECL(MPID_STATE_MPIDI_WIN_POST);

    MPIDI_RMA_FUNC_ENTER(MPID_STATE_MPIDI_WIN_POST);

    MPIU_ERR_CHKANDJUMP(win_ptr->epoch_state != MPIDI_EPOCH_NONE &&
                        win_ptr->epoch_state != MPIDI_EPOCH_START,
                        mpi_errno, MPI_ERR_RMA_SYNC, "**rmasync");

    /* Track access epoch state */
    if (win_ptr->epoch_state == MPIDI_EPOCH_START)
        win_ptr->epoch_state = MPIDI_EPOCH_PSCW;
    else
        win_ptr->epoch_state = MPIDI_EPOCH_POST;

    /* Even though we would want to reset the fence counter to keep
     * the user from using the previous fence to mark the beginning of
     * a fence epoch if he switched from fence to lock-unlock
     * synchronization, we cannot do this because fence_issued must be
     * updated collectively */

    /* In case this process was previously the target of passive target rma
     * operations, we need to take care of the following...
     * Since we allow MPI_Win_unlock to return without a done ack from
     * the target in the case of multiple rma ops and exclusive lock,
     * we need to check whether there is a lock on the window, and if
     * there is a lock, poke the progress engine until the operations
     * have completed and the lock is therefore released. */
    if (win_ptr->current_lock_type != MPID_LOCK_NONE)
    {
	MPID_Progress_state progress_state;
	
	MPIU_INSTR_DURATION_START(winpost_clearlock);
	/* poke the progress engine */
	MPID_Progress_start(&progress_state);
	while (win_ptr->current_lock_type != MPID_LOCK_NONE)
	{
	    mpi_errno = MPID_Progress_wait(&progress_state);
	    /* --BEGIN ERROR HANDLING-- */
	    if (mpi_errno != MPI_SUCCESS) {
		MPID_Progress_end(&progress_state);
		MPIU_ERR_SETANDJUMP(mpi_errno,MPI_ERR_OTHER,"**winnoprogress");
	    }
	    /* --END ERROR HANDLING-- */
	    MPIU_INSTR_DURATION_INCR(winpost_clearlock,0,1);
	}
	MPID_Progress_end(&progress_state);
	MPIU_INSTR_DURATION_END(winpost_clearlock);
    }
        
    post_grp_size = post_grp_ptr->size;
        
    /* initialize the completion counter */
    win_ptr->my_counter = post_grp_size;
        
    if ((assert & MPI_MODE_NOCHECK) == 0)
    {
        MPI_Request *req;
        MPI_Status *status;

	MPIU_INSTR_DURATION_START(winpost_sendsync);
 
	/* NOCHECK not specified. We need to notify the source
	   processes that Post has been called. */  
	
	/* We need to translate the ranks of the processes in
	   post_group to ranks in win_ptr->comm_ptr, so that we
	   can do communication */
            
	MPIU_CHKLMEM_MALLOC(ranks_in_post_grp, int *, 
			    post_grp_size * sizeof(int),
			    mpi_errno, "ranks_in_post_grp");
	MPIU_CHKLMEM_MALLOC(ranks_in_win_grp, int *, 
			    post_grp_size * sizeof(int),
			    mpi_errno, "ranks_in_win_grp");
        
	for (i=0; i<post_grp_size; i++)
	{
	    ranks_in_post_grp[i] = i;
	}
        
	win_comm_ptr = win_ptr->comm_ptr;

        mpi_errno = MPIR_Comm_group_impl(win_comm_ptr, &win_grp_ptr);
	if (mpi_errno) MPIU_ERR_POP(mpi_errno);
	

        mpi_errno = MPIR_Group_translate_ranks_impl(post_grp_ptr, post_grp_size, ranks_in_post_grp,
                                                    win_grp_ptr, ranks_in_win_grp);
        if (mpi_errno) MPIU_ERR_POP(mpi_errno);
	
        rank = win_ptr->myrank;
	
	MPIU_CHKLMEM_MALLOC(req, MPI_Request *, post_grp_size * sizeof(MPI_Request), mpi_errno, "req");
        MPIU_CHKLMEM_MALLOC(status, MPI_Status *, post_grp_size*sizeof(MPI_Status), mpi_errno, "status");