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A Distributed Framework for DSP Multicomputers


 
Concept

The key feature of IDSP is the assumption of a model of distributed application that consists of a graph of cooperating DSP algorithms running in one or more machines. A node in the graph represents an algorithm, run in the context of a task known as an operator. An arrow represents a data stream:

IDSP dynamically creates one or more instances of a given application (group), assigning operators to processors following either an ad-hoc or a load-balancing approach.

 Software Architecture

IDSP shows a microkernel architecture.There are are two kinds of operators: algorithm operators, running DSP algorithms, and server operators, that provide system services, such as the creation of operators and groups. The group server implements the GRP interface, the operator server the OPR interface, etc. 

IDSP currently uses DSP/BIOS for easier portability between the TMS320C6x, though just TSK and SEM DSP/BIOS services are used, for basic concurrent support. Migration to other RTOS, therefore, is straightforward.

 Interfaces

IDSP is composed by six public interfaces. 

  • KNL: Basic task management and communication. 
  • GC: MPI-like location-transparent group communication. 
  • RPC: Amoeba-like RPC communication 
  • OPR: Management of remote operators 
  • GRP: Managements of groups
  • CHN: High level 3L Diamond-like channel communication
    		•
    Performance

    Next figure shows the time taken to synchronous primitives to send a message. A SundanceTM SMT310Q multi-computer board with four Texas Instruments TMSC6102 DSP processors has been our test environment. As a reference, we measured the DSP/BIOS MBX_post primitive.


     
     

     

    		 Code size

    IDSP is small. The DSP/BIOS text segment size is around 25 Kbytes. The text sizes of IDSP interfaces are:

    Kernel

       GRP 0C20h
       OPR 1000h
       KNL 1560h 
       COM 18E0h
       LNK 1380h 
     + ISR 0340h
           6120h =   24864 bytes

    Group and RPC communication

       GC  04C0h 
     + RPC 0400h
            8C0h =    2240 bytes

    Channel communication

       CHN 1720h =    5920 bytes

    TOTAL = 33024 bytes (< 33 Kb)

    		 Target Hardware

    Idsp currently runs on:

    1) TMS320C6711 DSP Starter Kit (DSK), a Texas Instruments C6711-based DSP board

    2) SundanceTM PCI SMT310Q multi-computer:

    Last change: April/01/2004

    IDSP
    Universidad de Extremadura
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    Tel: +34 27 25 72 65 Fax: +34 27 25 72 02
    E-Mail: juancarl@unex.es