[svn-r1035] t_file.c:

    Added a new test to verify the MPIO can support independent
    overlapping writes.
testphdf5.c:
    Bracketed the MPIO write test with a #ifdef so that it is
    tested only when the explicitely turned on.

Platform tested:
    O2K.

1 files changed, 136 insertions, 0 deletions

diff --git a/testpar/t_file.c b/testpar/t_file.c
index 0c64092..c615663 100644
--- a/testpar/t_file.c
+++ b/testpar/t_file.c
@@ -78,3 +78,139 @@ test_split_comm_access(char *filename[])
 	}
     }
 }
+
+
+
+/*
+ * MPIO independent overlapping writes.
+ *
+ * First n-1 processes open 1 file.
+ * Each of the n-1 process writes chunks of data to the file in round-robin
+ * fashion, in a interleaved but not overlapped fashion.  Using increasing
+ * chunk sizes for the benefits of testing different write sizes and also
+ * reducing the numbers of writes.
+ *
+ * Last process (n-1) just waits.
+ * First n-1 processes finish writing and cloose the file.
+ * Last process opens the same file and verifies the data.
+ */
+
+#define MPIO_TEST_WRITE_SIZE 1024*1024     /* 1 MB */
+
+void
+test_mpio_overlap_writes(char *filename[])
+{
+    int mpi_size, mpi_rank;
+    MPI_Comm comm;
+    MPI_Info info = MPI_INFO_NULL;
+    int color, mrc;
+    MPI_File	fh;
+    int newrank, newprocs;
+    hid_t fid;			/* file IDs */
+    hid_t acc_tpl;		/* File access properties */
+    herr_t ret;			/* generic return value */
+    int i;
+    char  buf[4093];		/* use some prime number for size */
+    int bufsize = sizeof(buf);
+    int stride;
+    MPI_Offset  mpi_off;
+    MPI_Status  mpi_stat;
+
+
+    if (verbose)
+	printf("MPIO independent overlapping writes test on file %s\n",
+	    filename[0]);
+
+    /* set up MPI parameters */
+    MPI_Comm_size(MPI_COMM_WORLD,&mpi_size);
+    MPI_Comm_rank(MPI_COMM_WORLD,&mpi_rank);
+
+    /* Need at least 2 processes */
+    VRFY((mpi_size >= 2), "Has at least 2 processes");
+
+    /* splits processes 0 to n-2 into one comm. and the last one into another */
+    color = ((mpi_rank < (mpi_size - 1)) ? 0 : 1);
+    mrc = MPI_Comm_split (MPI_COMM_WORLD, color, mpi_rank, &comm);
+    VRFY((mrc==MPI_SUCCESS), "Comm_split succeeded");
+
+    if (color==0){
+	/* First n-1 processes (color==0) open a file and write it */
+	mrc = MPI_File_open(comm, filename[0], MPI_MODE_CREATE|MPI_MODE_RDWR,
+		info, &fh);
+	VRFY((mrc==MPI_SUCCESS), "");
+
+	stride = 1;
+	mpi_off = mpi_rank*stride;
+	while (mpi_off < MPIO_TEST_WRITE_SIZE){
+	    /* make sure the write does not exceed the TEST_WRITE_SIZE */
+	    if (mpi_off+stride > MPIO_TEST_WRITE_SIZE)
+		stride = MPIO_TEST_WRITE_SIZE - mpi_off;
+
+	    /* set data to some trivial pattern for easy verification */
+	    for (i=0; i<stride; i++)
+		buf[i] = (mpi_off+i) & 0x7f;
+	    mrc = MPI_File_write_at(fh, mpi_off, buf, stride, MPI_BYTE,
+		    &mpi_stat);
+	    VRFY((mrc==MPI_SUCCESS), "");
+	    
+	    /* move the offset pointer to last byte written by all processes */
+	    mpi_off += (mpi_size - 1 - mpi_rank) * stride;
+
+	    /* Increase chunk size without exceeding buffer size. */
+	    /* Then move the starting offset for next write. */
+	    stride *= 2;
+	    if (stride > bufsize)
+		stride = bufsize;
+	    mpi_off += mpi_rank*stride;
+	}
+
+	/* close file and free the communicator */
+	mrc = MPI_File_close(&fh);
+	VRFY((mrc==MPI_SUCCESS), "MPI_FILE_CLOSE");
+	mrc = MPI_Comm_free(&comm);
+	VRFY((mrc==MPI_SUCCESS), "MPI_Comm_free");
+    
+	/* sync with the other waiting processes */
+	mrc = MPI_Barrier(MPI_COMM_WORLD);
+	VRFY((mrc==MPI_SUCCESS), "Sync after writes");
+    }else{
+	/* last process waits till writes are done,
+	 * then opens file to verify data.
+	 */
+	mrc = MPI_Barrier(MPI_COMM_WORLD);
+	VRFY((mrc==MPI_SUCCESS), "Sync after writes");
+
+	mrc = MPI_File_open(comm, filename[0], MPI_MODE_RDONLY,
+		info, &fh);
+	VRFY((mrc==MPI_SUCCESS), "");
+
+	stride = bufsize;
+	for (mpi_off=0; mpi_off < MPIO_TEST_WRITE_SIZE; mpi_off += bufsize){
+	    /* make sure it does not read beyond end of data */
+	    if (mpi_off+stride > MPIO_TEST_WRITE_SIZE)
+		stride = MPIO_TEST_WRITE_SIZE - mpi_off;
+	    mrc = MPI_File_read_at(fh, mpi_off, buf, stride, MPI_BYTE,
+		    &mpi_stat);
+	    VRFY((mrc==MPI_SUCCESS), "");
+	    for (i=0; i<stride; i++){
+		if (buf[i] != ((mpi_off+i) & 0x7f))
+		    printf("proc %d: found data error at [%d], expect %d, got %d\n",
+		    mpi_rank, mpi_off+i, mpi_off & 0x7f, buf[0]);
+	    }
+	}
+
+	/* close file and free the communicator */
+	mrc = MPI_File_close(&fh);
+	VRFY((mrc==MPI_SUCCESS), "MPI_FILE_CLOSE");
+	mrc = MPI_Comm_free(&comm);
+	VRFY((mrc==MPI_SUCCESS), "MPI_Comm_free");
+    }
+
+    /*
+     * one more sync to ensure all processes have done reading
+     * before ending this test.
+     */
+    mrc = MPI_Barrier(MPI_COMM_WORLD);
+    VRFY((mrc==MPI_SUCCESS), "Sync before leaving test");
+}
+