1
1
openmpi/ompi/mca/btl/sm/btl_sm_fifo.h
Eugene Loh 5bbf5ba7d7 First putback of some sm BTL latency optimizations:
* The main thing done here is to convert from multiple FIFOs/queues per
  receiver (each receiver has one FIFO for each sender) to a single FIFO/queue
  per receiver (all senders sharing the same FIFO for a given receiver).
* This requires rewriting the FIFO support, so that
  ompi/class/ompi_[circular_buffer_]fifo.h is no longer used and FIFO
  support is instead in btl_sm.h.
* The number of FIFOs per receiver is actually an MCA tunable parameter,
  but it appears that 1 or possibly 2 FIFOs (even for 112 local processes)
  per receiver is sufficient.

This commit was SVN r20578.
2009-02-17 15:58:15 +00:00

57 строки
2.1 KiB
C

#ifndef MCA_BTL_SM_FIFO_H
#define MCA_BTL_SM_FIFO_H
#include "btl_sm.h"
#include "btl_sm_endpoint.h"
/*
* FIFO_MAP(x) defines which FIFO on the receiver should be used
* by sender rank x. The map is some many-to-one hash.
*
* FIFO_MAP_NUM(n) defines how many FIFOs the receiver has for
* n senders.
*
* That is,
*
* for all 0 <= x < n:
*
* 0 <= FIFO_MAP(x) < FIFO_MAP_NUM(n)
*
* For example, using some power-of-two nfifos, we could have
*
* FIFO_MAP(x) = x & (nfifos-1)
* FIFO_MAP_NUM(n) = min(nfifos,n)
*
* Interesting limits include:
*
* nfifos very large: In this case, each sender has its
* own dedicated FIFO on each receiver and the receiver
* has one FIFO per sender.
*
* nfifos == 1: In this case, all senders use the same
* FIFO and each receiver has just one FIFO for all senders.
*/
#define FIFO_MAP(x) ((x) & (mca_btl_sm_component.nfifos - 1))
#define FIFO_MAP_NUM(n) ( (mca_btl_sm_component.nfifos) < (n) ? (mca_btl_sm_component.nfifos) : (n) )
#define MCA_BTL_SM_FIFO_WRITE(endpoint_peer, my_smp_rank, \
peer_smp_rank, hdr, resend, rc) \
do { \
sm_fifo_t* fifo = &(mca_btl_sm_component.fifo[peer_smp_rank][FIFO_MAP(my_smp_rank)]); \
\
opal_atomic_lock(&(fifo->head_lock)); \
/* post fragment */ \
if(sm_fifo_write(hdr, fifo) != OMPI_SUCCESS) { \
btl_sm_add_pending(endpoint_peer, hdr, resend); \
rc = OMPI_ERR_RESOURCE_BUSY; \
} else { \
MCA_BTL_SM_SIGNAL_PEER(endpoint_peer); \
rc = OMPI_SUCCESS; \
} \
opal_atomic_unlock(&(fifo->head_lock)); \
} while(0)
#endif