HDF5 io_ops path analysis

hdf5-parallel_io.dot

digraph G {
    label = "Parallel I/O in HDF5"
    forcelabels = true
    rankdir = "TB"
    compound = true
    splines = true # true polyline curved
    node [style=""]

    subgraph cluster_h5dpkg_h {
        label = "H5Dpkg.h"
        style = "filled"
        fillcolor = "gray"
        s_struct[
            shape = "record"
            style = "filled"
            fillcolor = "white"
            label = "{
                <layout> H5D_layout_ops_t \{\l\     H5D_layout_read_func_t  par_read;\l\     H5D_layout_write_func_t par_write;\l\}\l|
                <io_info> H5D_io_info_t \{\l\     hbool_t using_mpi_vfd;\l\}\l|
                <chunk_map> H5D_chunk_map_t \{\l\     H5D_chunk_info_t **select_chunk;\l\}\l}"
        ]
    }

    subgraph cluster_h5dchunk {
        label = "H5Dchunk.c"
        style = "filled"
        fillcolor = "khaki"
        node[style="filled" fillcolor="white"]

        s_chunk_struct[
            shape = "record"
            label="{
            <file_iter> H5D_chunk_file_iter_ud_t \{\l\    const H5D_io_info_t *io_info;\l\}\l|
            <lops> H5D_layout_ops_t H5D_LOPS_CHUNK = \{\l\    .ser_read = H5D__chunk_read,\l\    .par_read = H5D__chunk_collective_read\l\}\l}
            "
        ]

        subgraph cluster_chunk_read {
            label = <<b><font point-size='16'>H5D__chunk_read()</font></b>>
            fillcolor="moccasin"

            s_chunk_read_init_chunk[
                shape = "box"
                label = "chunk = H5D_CHUNK_GET_FIRST_NODE()"
            ]
            s_chunk_read_next_chunk[
                shape = "box"
                label = "chunk = H5D_CHUNK_GET_NEXT_NODE()"
            ]
            s_chunk_read_test_chunk[
                shape = "diamond"
                label = "Got chunk?"
            ]
            s_single_read[
                shape = "box"
                label = "io_info->io_ops.single_read(...)"
            ]

            s_chunk_read_init_chunk -> s_chunk_read_test_chunk
            s_chunk_read_test_chunk-> s_single_read [label="yes"]
            s_single_read -> s_chunk_read_next_chunk -> s_chunk_read_test_chunk
        }

        s_chunk_struct:lops -> s_chunk_read_init_chunk [lhead=cluster_chunk_read color="magenta" penwidth=2 style="dashed"]
    }

    subgraph cluster_h5dcontig {
        label = "H5Dcontig.c"
        style = "filled"
        fillcolor = "khaki"
        node[style="filled" fillcolor="white"]

        s_lops_contig[
            shape = "box"
            label = "H5D_layout_ops_t H5D_LOPS_CONTIG = {\l    .ser_read = H5D__contig_read,\l    .par_read = H5D__contig_collective_read\l}\l"
        ]

        subgraph cluster_contig_read {
            label = <<b><font point-size='16'>H5D__contig_read()</font></b>>
            fillcolor="moccasin"

            s_contig_single_read[
                shape = "box"
                label = "io_info->io_ops.single_read(...)"
            ]
        }

        s_lops_contig -> s_contig_single_read [lhead=cluster_contig_read style="dashed"]
    }

    subgraph cluster_h5dmpio {
        label = "MPI-based I/O (H5Dmpio.c)"
        bgcolor = "gold"

        s_optimized_read_fn[
            shape = "record"
            style = "filled"
            fillcolor = "white"
            label = "{
                H5D__chunk_collective_read()|
                H5D__contig_collective_read()|
                H5D__mpio_select_read()}
            "
        ]
    }
    subgraph cluster_h5dio {
        label = <<b><font point-size='16'>H5D__read()</font></b> (H5Dio.c)>
        bgcolor = "ivory"

        s_read[shape="box" label="io_info->io_ops.multi_read(...)" style="filled" fillcolor="floralwhite"]

        subgraph cluster_ioinfo_init_fn {
            label = "H5D__ioinfo_init()"
            bgcolor = "floralwhite"
            s_io_ops[
                shape="box"
                label = "io_info->io_ops = {\l\    .multi_read = dset->shared->layout.ops->ser_read, \l\    .single_read = conv_needed ? H5D__scatgath_read :  H5D__select_read\l\}\l"
            ]
        }

        subgraph cluster_ioinfo_adjust_fn {
            label = "H5D__ioinfo_adjust()"
            bgcolor = "floralwhite"
            t_adjust_mpi_vfd[shape="diamond" label="io_info->using_mpi_vfd?"]
            t_adjust_collective_io[shape="diamond" label="Is collective I/O possible?"]
        }

        subgraph cluster_collective_read {
            label = "Collective I/O"
            bgcolor = "floralwhite"
            s_io_ops_collective[
                shape = "box"
                label = "io_info->io_ops = {\l\    .multi_read = dset->shared->layout.ops->par_read, \l\    .single_read = H5D__mpio_select_read\l\}\l"
            ]
        }

        s_io_ops -> t_adjust_mpi_vfd [ltail=cluster_ioinfo_init_fn]
        t_adjust_mpi_vfd -> t_adjust_collective_io [label="yes" color="darkgreen" penwidth=2]
        t_adjust_mpi_vfd -> s_read [label="no" color="red" penwidth=2]

        t_adjust_collective_io -> s_io_ops_collective [label="yes" lhead="cluster_collective_read" color="darkgreen" penwidth=2]
        t_adjust_collective_io -> s_read [label="no" color="red" penwidth=2]

        s_io_ops_collective -> s_read [color="darkgreen" penwidth=2]
        
        s_read -> s_optimized_read_fn:n [lhead="cluster_h5dmpio" label="MPI-based I/O" style="dashed" color="darkgreen" penwidth=2 minlen=2]
        s_read -> s_chunk_read_init_chunk [lhead=cluster_chunk_read label="Chunked dataset, no MPI" style="dashed" color="red" penwidth=2]
        s_read -> s_contig_single_read [lhead=cluster_contig_read label="Contiguous dataset, no MPI" style="dashed" color="red" penwidth=2]
    }

    subgraph cluster_vol {
        label = "VOL driver (H5VLconnector.h, H5VLnative.c)"
        bgcolor = "turquoise"

        s_dataset_cls[
            shape = "box"
            style = "filled"
            color = "white"
            label = "H5VL_native_cls_g.dataset_cls = {\l    .read = H5VL__native_dataset_read\l}\l"
        ]

        s_native_dataset_read[
            shape = "box"
            style = "filled"
            color = "white"
            label = "H5VL__native_dataset_read()"
        ]

        s_dataset_cls -> s_native_dataset_read [style="dashed"]
        s_native_dataset_read -> s_io_ops:n [lhead=cluster_h5dio]
    }
}