Changes between Version 1 and Version 2 of mapping_info


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Timestamp:
Oct 26, 2014, 11:17:12 AM (10 years ago)
Author:
alain
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  • mapping_info

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    33
     4== C mapping data structure ==
    45
     6The C binary mapping data structure, is used by the GIET_VM in the boot phase to map one or several multi-threaded user applications on a
     7generic multi-processors, multi-clusters architecture. The next section describes how this this C binary structure can be generated by the ''genmap'' tool from a source description using the PYTHON language.
    58
    6 The C binary mapping data structure, is used by the GIET_VM to map one or several multi-threaded user applications on a
    7 generic multi-processors, multi-clusters architecture. This C binary structure is generated by the ''genmap'' tool from a source description
    8 using PYTHON.
     9The C mapping data structure contains the following informations:
    910
    10 This mapping is statically build by the GIET-VM bootloader in the boot phase:
    11  1.  It contains a description of the target clusterized hardware architecture.The number of cluster is variable (can be one). The number of processors per cluster is variable (can be one). The number of peripherals and coprocessor per cluster is variable. The number of physical memory banks per cluster is variable.
    12  2. It contains a description of the user applications (an user application is called a ''vspace'') to be launched on the platform. The number of parallel ''tasks'' per application is variable (can be one). Multi-Writer/Multi-Reader communication channels between tasks are supported. Each vspace contains a variable number of virtual segments (called ''vsegs''). The number of vspace can be one.
    13  3. It contains the mapping directives: The tasks are statically allocated to processors. The various software objects (user and kernel code segments, tasks stacks, tasks heaps, communication channels, etc.) are called ''vobjs'', and are statically placed on the distributed physical memory banks (called ''psegs''),  using the paged virtual memory.
     11 1.  It contains a description of the target, clusterized, hardware architecture, with the following constraints: The clusters are identified by the (x,y) coordinates in a 2D mesh topology. The number of clusters is variable (can be one). The number of processors per cluster is variable (can be one). The number of  physical memory banks is variable (up to one physical memory bank per cluster. Most peripherals are ''external'' and  localized in one specific I/O cluster.
     12 2. It contains a description of the user applications to be launched on the platform. An user application is characterized by a a virtual address space, called a ''vspace''. The number of parallel ''tasks'' per application is variable (can be one). Multi-Writer/Multi-Reader communication channels between tasks are supported. Each vspace contains a variable number of virtual segments, called ''vsegs''. The number of vspace can be one.
     13 3. It contains the mapping directives: The tasks are statically allocated to processors. The various software objects (user and kernel code segments, tasks stacks, tasks heaps, communication channels, etc.) are called ''vobjs'', and are statically placed on the distributed physical memory banks (called ''psegs''),  using the page tables (one page table per vspace) that define the mapping of the vsegs on the psegs.
    1414
    1515The C binary mapping data structure is defined in the [source:soft/giet_vm/giet_xml/mapping_info.h mapping_info.h] file, and is organised as the concatenation of a fixed size header, and 11 variable size arrays:
    … …  
    2626 * mapping_periph_t   periph[]
    2727It is intended to be stored in memory in the seg_boot_mapping segment.
     28
     29== Python Mapping General =
     30
     31A specific mapping requires at least two python files:
     32 * The '''arch.py''' file is attached to a given hardware architecture. It describes both the (possibly generic) hardware architectures, and the mapping of the kernel software objects on this architecture.
     33 * The '''appli.py''' file is attached to a given user application. It describes the both the application structure (tasks and communication channels), and the mapping of the application tasks and software objects on the architecture.
     34
     35The various Python Classes used by these these files are defined in the [source:soft/giet_vm/giet_python/mapping.py mapping.py] file.
     36
     37== Python Architecture description ===
     38
     39To define an architecture, you must use the following constructors:
     40
     41=== Class Mapping ===
     42
     43The following constructor build a mapping object and define the target architecture general parameters:
     44
     45mapping = Mapping( name           # mapping name
     46                                 x_size          # number of clusters in a row of the 2D mesh
     47                                 y_size           # number of clusters in a column of the 2D mesh               
     48                                 nprocs          # number of processors per cluster     
     49                                 x_width        # number of bits to encode X coordinate in paddr (default = 4)
     50                                 y_width         # number of bits to encode Y coordinate in paddr (default = 4)
     51                                 p_width         # number of bits to encode local processor index (default = 4)
     52                                 paddr_width  # number of bits in physical address   
     53                                 coherence      # Boolean true if hardware cache coherence         
     54                                 irq_per_proc   # number of IRQ lines between XCU and proc 
     55                                 use_ramdisk    # Boolean true if the architecture contains a RamDisk
     56                                 x_io                 # io_cluster X coordinate         
     57                                 y_io                  # io_cluster Y coordinate
     58                                 peri_increment  # peri_increment,
     59                                 ram_base          # Physical memory bank base address in cluster [0,0]
     60                                 ram_size           # ram_size )
     61
     62mapping = Mapping
     63== Application description : appli.py ===