implement the ring example with asynchronous calls

mpi/Makefile.am

@@ -54,6 +54,7 @@ check_PROGRAMS +=					\
 	tests/mpi_isend					\
 	tests/mpi_irecv					\
 	tests/ring					\
+	tests/ring_async				\
 	tests/block_interface
 
 tests_mpi_isend_LDADD =					\
@@ -80,6 +81,12 @@ tests_ring_LDADD =					\
 tests_ring_SOURCES =					\
 	tests/ring.c
 
+tests_ring_async_LDADD =					\
+	libstarpumpi.la
+
+tests_ring_async_SOURCES =					\
+	tests/ring_async.c
+
 tests_block_interface_LDADD =				\
 	libstarpumpi.la
 
@@ -88,4 +95,5 @@ tests_block_interface_SOURCES =				\
 
 if USE_CUDA
 tests_ring_SOURCES += tests/ring_kernel.cu
+tests_ring_async_SOURCES += tests/ring_kernel.cu
 endif

mpi/starpu_mpi.c

@@ -71,8 +71,6 @@ static void _handle_new_mpi_irecv(struct starpu_mpi_req_s *req)
 }
 
 
-/* NB: there is no status field here as we (may) return before the request is
- * actually transmitted to MPI. */
 int starpu_mpi_irecv(starpu_data_handle data_handle, struct starpu_mpi_req_s *req,
 		int source, int mpi_tag, MPI_Comm comm,
 		void (*callback)(void *))

mpi/tests/ring_async.c

@@ -0,0 +1,131 @@
+/*
+ * StarPU
+ * Copyright (C) INRIA 2008-2009 (see AUTHORS file)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * See the GNU Lesser General Public License in COPYING.LGPL for more details.
+ */
+
+#include <starpu_mpi.h>
+
+#define NITER	2048
+
+unsigned token = 42;
+starpu_data_handle token_handle;
+
+#ifdef USE_CUDA
+extern void increment_cuda(starpu_data_interface_t *buffers, __attribute__ ((unused)) void *_args);
+#endif
+
+void increment_core(starpu_data_interface_t *buffers, __attribute__ ((unused)) void *_args)
+{
+	unsigned *tokenptr = (unsigned *)buffers[0].vector.ptr;
+	(*tokenptr)++;
+}
+
+static starpu_codelet increment_cl = {
+	.where = CORE|CUDA,
+#ifdef USE_CUDA
+	.cuda_func = increment_cuda,
+#endif
+	.core_func = increment_core,
+	.nbuffers = 1
+};
+
+void increment_token(void)
+{
+	struct starpu_task *task = starpu_task_create();
+
+	task->cl = &increment_cl;
+	
+	task->buffers[0].handle = token_handle;
+	task->buffers[0].mode = STARPU_RW;
+
+	task->synchronous = 1;
+
+	starpu_submit_task(task);
+}
+
+int main(int argc, char **argv)
+{
+	MPI_Init(NULL, NULL);
+
+	int rank, size;
+
+	MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+	MPI_Comm_size(MPI_COMM_WORLD, &size);
+
+	if (size < 2)
+	{
+		if (rank == 0)
+			fprintf(stderr, "We need at least 2 processes.\n");
+
+		MPI_Finalize();
+		return 0;
+	}
+
+	starpu_init(NULL);
+	starpu_mpi_initialize();
+
+	starpu_register_vector_data(&token_handle, 0, (uintptr_t)&token, 1, sizeof(unsigned));
+
+	unsigned nloops = NITER;
+	unsigned loop;
+
+	unsigned last_loop = nloops - 1;
+	unsigned last_rank = size - 1;
+
+	for (loop = 0; loop < nloops; loop++)
+	{
+		int tag = loop*size + rank;
+
+		if (!((loop == 0) && (rank == 0)))
+		{
+			token = 0;
+			MPI_Status status;
+			struct starpu_mpi_req_s req;
+			starpu_mpi_irecv(token_handle, &req, (rank+size-1)%size, tag, MPI_COMM_WORLD, NULL);
+			starpu_mpi_wait(&req, &status);
+		}
+		else {
+			token = 0;
+			fprintf(stdout, "Start with token value %d\n", token);
+		}
+
+		increment_token();
+		
+		if (!((loop == last_loop) && (rank == last_rank)))
+		{
+			struct starpu_mpi_req_s req;
+			MPI_Status status;
+			starpu_mpi_isend(token_handle, &req, (rank+1)%size, tag+1, MPI_COMM_WORLD, NULL);
+			starpu_mpi_wait(&req, &status);
+		}
+		else {
+
+			starpu_sync_data_with_mem(token_handle, STARPU_R);
+			fprintf(stdout, "Finished : token value %d\n", token);
+			starpu_release_data_from_mem(token_handle);
+		}
+	}
+
+	starpu_mpi_shutdown();
+	starpu_shutdown();
+
+	MPI_Finalize();
+
+	if (rank == last_rank)
+	{
+		STARPU_ASSERT(token == nloops*size);
+	}
+
+	return 0;
+}