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-rw-r--r--testpar/t_file.c136
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");
+}
+