diff options
Diffstat (limited to 'testpar/t_file.c')
| -rw-r--r-- | testpar/t_file.c | 136 |
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"); +} + |