Add functions to test for cached values

doc/doxygen/chapters/410_mpi_support.doxy

@@ -572,6 +572,9 @@ add fine-graph starpu_mpi_cache_flush() calls during the algorithm; the effect
 for the data deallocation will be the same, but it will additionally release some
 pressure from the StarPU-MPI cache hash table during task submission.
 
+One can determine whether a piece of is cached with starpu_mpi_cached_receive()
+and starpu_mpi_cached_send().
+
 The whole caching behavior can be disabled thanks to the \ref STARPU_MPI_CACHE
 environment variable. The variable \ref STARPU_MPI_CACHE_STATS can be set to <c>1</c>
 to enable the runtime to display messages when data are added or removed

doc/doxygen/chapters/api/mpi.doxy

@@ -248,6 +248,16 @@ function has to be called at the same point of task graph submission by all the
 function does nothing if the cache mechanism is disabled (see
 \ref STARPU_MPI_CACHE).
 
+\fn int starpu_mpi_cached_receive(starpu_data_handle_t data_handle);
+\ingroup API_MPI_Support
+Test whether \p data_handle is cached for reception, i.e. the value was
+previously received from the owner node, and not flushed since then.
+
+\fn int starpu_mpi_cached_send(starpu_data_handle_t data_handle, int dest);
+\ingroup API_MPI_Support
+Test whether \p data_handle is cached for emission to node \p dest , i.e. the
+value was previously sent to \p dest, and not flushed since then.
+
 @name MPI Insert Task
 \anchor MPIInsertTask
 \ingroup API_MPI_Support

mpi/include/starpu_mpi.h

@@ -1,6 +1,6 @@
 /* StarPU --- Runtime system for heterogeneous multicore architectures.
  *
- * Copyright (C) 2009-2012, 2014-2016  Université de Bordeaux
+ * Copyright (C) 2009-2012, 2014-2017  Université de Bordeaux
  * Copyright (C) 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017  CNRS
  * Copyright (C) 2016  Inria
  *
@@ -75,6 +75,9 @@ void starpu_mpi_comm_amounts_retrieve(size_t *comm_amounts);
 void starpu_mpi_cache_flush(MPI_Comm comm, starpu_data_handle_t data_handle);
 void starpu_mpi_cache_flush_all_data(MPI_Comm comm);
 
+int starpu_mpi_cached_receive(starpu_data_handle_t data_handle);
+int starpu_mpi_cached_send(starpu_data_handle_t data_handle, int dest);
+
 int starpu_mpi_comm_size(MPI_Comm comm, int *size);
 int starpu_mpi_comm_rank(MPI_Comm comm, int *rank);
 int starpu_mpi_world_rank(void);

mpi/src/starpu_mpi_cache.c

@@ -1,7 +1,7 @@
 /* StarPU --- Runtime system for heterogeneous multicore architectures.
  *
  * Copyright (C) 2011, 2012, 2013, 2014, 2015, 2016, 2017  CNRS
- * Copyright (C) 2011-2016  Université de Bordeaux
+ * Copyright (C) 2011-2017  Université de Bordeaux
  * Copyright (C) 2014 INRIA
  *
  * StarPU is free software; you can redistribute it and/or modify
@@ -319,6 +319,13 @@ void *_starpu_mpi_cache_received_data_get(starpu_data_handle_t data, int mpi_ran
 	return already_received;
 }
 
+int starpu_mpi_cached_receive(starpu_data_handle_t data_handle)
+{
+	int owner = starpu_mpi_data_get_rank(data_handle);
+	void *already_received = _starpu_mpi_cache_received_data_get(data_handle, owner);
+	return already_received != NULL;
+}
+
 void *_starpu_mpi_cache_sent_data_set(starpu_data_handle_t data, int dest)
 {
 	struct _starpu_data_entry *already_sent;
@@ -344,3 +351,24 @@ void *_starpu_mpi_cache_sent_data_set(starpu_data_handle_t data, int dest)
 	STARPU_PTHREAD_MUTEX_UNLOCK(&_cache_sent_mutex[dest]);
 	return already_sent;
 }
+
+void *_starpu_mpi_cache_sent_data_get(starpu_data_handle_t data, int dest)
+{
+	struct _starpu_data_entry *already_sent;
+
+	if (_starpu_cache_enabled == 0) return NULL;
+
+	STARPU_MPI_ASSERT_MSG(dest < _starpu_cache_comm_size, "Node %d invalid. Max node is %d\n", dest, _starpu_cache_comm_size);
+
+	STARPU_PTHREAD_MUTEX_LOCK(&_cache_sent_mutex[dest]);
+	HASH_FIND_PTR(_cache_sent_data[dest], &data, already_sent);
+	STARPU_PTHREAD_MUTEX_UNLOCK(&_cache_sent_mutex[dest]);
+	return already_sent;
+}
+
+int starpu_mpi_cached_send(starpu_data_handle_t data_handle, int dest)
+{
+	void *already_sent = _starpu_mpi_cache_sent_data_get(data_handle, dest);
+	return already_sent != NULL;
+}
+

mpi/src/starpu_mpi_cache.h

@@ -1,7 +1,7 @@
 /* StarPU --- Runtime system for heterogeneous multicore architectures.
  *
  * Copyright (C) 2011, 2012, 2013, 2014, 2015, 2016  CNRS
- * Copyright (C) 2011-2014  Université de Bordeaux
+ * Copyright (C) 2011-2014, 2017  Université de Bordeaux
  * Copyright (C) 2014 INRIA
  *
  * StarPU is free software; you can redistribute it and/or modify
@@ -44,6 +44,7 @@ void _starpu_mpi_cache_received_data_clear(starpu_data_handle_t data);
  * If the data is NOT available in the cache, add it to the cache and return NULL
  */
 void *_starpu_mpi_cache_sent_data_set(starpu_data_handle_t data, int dest);
+void *_starpu_mpi_cache_sent_data_get(starpu_data_handle_t data, int dest);
 void _starpu_mpi_cache_sent_data_clear(MPI_Comm comm, starpu_data_handle_t data);
 
 void _starpu_mpi_cache_flush(MPI_Comm comm, starpu_data_handle_t data_handle);