1
1
openmpi/ompi/mca/coll/libnbc/nbc_ibarrier.c
Torsten Hoefler 6b22641669 added LibNBC (http://www.unixer.de/NBC) as collv1 (blocking) component.
I know it does not make much sense but one can play around with the
performance. Numbers are available at http://www.unixer.de/research/nbcoll/perf/.
This is the first step towards collv2. Next step includes the addition
of non-blocking functions to the MPI-Layer and the collv1 interface.

It implements all MPI-1 collective algorithms in a non-blocking manner.
However, the collv1 interface does not allow non-blocking collectives so
that all collectives are used blocking by the ompi-glue layer.

I wanted to add LibNBC as a separate subdirectory, but I could not
convince the buildsystem (and had not the time). So the component looks
pretty messy. It would be great if somebody could explain me how to move
all nbc*{c,h}, and {hb,dict}*{c,h} to a seperate subdirectory.

It's .ompi_ignored because I did not test it exhaustively yet.

This commit was SVN r11401.
2006-08-24 16:47:18 +00:00

76 строки
2.7 KiB
C

#include "nbc.h"
/* Dissemination implementation of MPI_Ibarrier */
int NBC_Ibarrier(MPI_Comm comm, NBC_Handle* handle) {
int round, rank, p, maxround, res, recvpeer, sendpeer;
NBC_Schedule *schedule;
res = NBC_Init_handle(handle, comm);
if(res != NBC_OK) { printf("Error in NBC_Init_handle(%i)\n", res); return res; }
res = MPI_Comm_rank(comm, &rank);
if (MPI_SUCCESS != res) { printf("MPI Error in MPI_Comm_rank() (%i)\n", res); return res; }
res = MPI_Comm_size(comm, &p);
if (MPI_SUCCESS != res) { printf("MPI Error in MPI_Comm_size() (%i)\n", res); return res; }
handle->tmpbuf=NULL;
#ifdef NBC_CACHE_SCHEDULE
/* there only one argument set per communicator -> hang it directly at
* the tree-position, NBC_Dict_size[...] is 0 for not initialized and
* 1 for initialized. NBC_Dict[...] is a pointer to the schedule in
* this case */
if(handle->comminfo->NBC_Dict_size[NBC_BARRIER] == 0) {
/* we did not init it yet */
#endif
schedule = malloc(sizeof(NBC_Schedule));
if (NULL == schedule) { printf("Error in malloc()\n"); return res; }
round = -1;
res = NBC_Sched_create(schedule);
if(res != NBC_OK) { printf("Error in NBC_Sched_create (%i)\n", res); return res; }
maxround = (int)ceil((log(p)/LOG2)-1);
do {
round++;
sendpeer = (rank + (1<<round)) % p;
/* add p because modulo does not work with negative values */
recvpeer = ((rank - (1<<round))+p) % p;
/* send msg to sendpeer */
res = NBC_Sched_send(NULL, false, 0, MPI_BYTE, sendpeer, schedule);
if (NBC_OK != res) { printf("Error in NBC_Sched_send() (%i)\n", res); return res; }
/* recv msg from recvpeer */
res = NBC_Sched_recv(NULL, false, 0, MPI_BYTE, recvpeer, schedule);
if (NBC_OK != res) { printf("Error in NBC_Sched_recv() (%i)\n", res); return res; }
/* end communication round */
if(round < maxround){
res = NBC_Sched_barrier(schedule);
if (NBC_OK != res) { printf("Error in NBC_Sched_barrier() (%i)\n", res); return res; }
}
} while (round < maxround);
res = NBC_Sched_commit(schedule);
if (NBC_OK != res) { printf("Error in NBC_Sched_commit() (%i)\n", res); return res; }
#ifdef NBC_CACHE_SCHEDULE
/* add it */
handle->comminfo->NBC_Dict[NBC_BARRIER] = (hb_tree*)schedule;
handle->comminfo->NBC_Dict_size[NBC_BARRIER] = 1;
} else {
/* we found it */
schedule = (NBC_Schedule*)handle->comminfo->NBC_Dict[NBC_BARRIER];
}
#endif
res = NBC_Start(handle, schedule);
if (NBC_OK != res) { printf("Error in NBC_Start() (%i)\n", res); return res; }
return NBC_OK;
}
/*void NBC_IBARRIER(MPI_Fint *comm, MPI_Fint *ierr) {
*ierr = NBC_Ibarrier(MPI_Comm comm, NBC_Handle* handle);
}*/