Subversion Repositories async_sdm_noc

Asynchronous Spatial Division Multiplexing Router for On-Chip Networks

Version: 0.1

On-chip networks or networks-on-chip (NoCs) are the on-chip communication fabric for

current and future multiprocessor SoCs (MPSoCs) and chip multiprocessors (CMPs).

Compared with synchronous NoCs, asynchronous NoCs have following benefits:

  * Tolerance to all kinds of delay variations caused by process, power and temperature

    variations.

  * Low transmission latency.

  * Zero dynamic power when idle.

  * Unified sync/async interface and easy clock domain integration.

Most NoCs use the wormhole flow control method. Many complex flow control methods are

built upon the wormhole method, such as virtual channel (VC), TDMA, and SDM. VC is the

most utilized flow control in both sync and async NoCs. However, it is found VC

compromises the throughput performance of asynchronous NoCs. This project provides a new

asynchronous router structure which use SDM rather than VC. It has been shown that SDM

achieve better throughput than VC in the same router configuration.

This project provide a reconfigurable asynchronous SDM router which can be configured

into a basic wormhole router or an SDM router with multiple virtual circuits in every

direction.

Features:

  * 5-port router for mesh network (0 south, 1 west, 2 north, 3 east, 4 local)

  * The dimension order routing (XY routing)

  * Available flow control methods: wormhole, SDM

  * Reconfigurable number of virtual circuits, buffer size, data width

  * Fully synthesizable router implementation

  * SystemC testbench provided

Languages:

  * Routers are written in synthesizable SystemVerilog

  * Test benches are provided by SystemC

Software requirements:

  * The open source Nangate 45nm cell library

  * Synopsys Design Compiler (Synthesis)

  * Cadence IUS -- NC Simulator (for SystemC/Verilog co-simulation)

File structure:

  * common                              files needed for both SDM and VC routers

   \- script                            synthesis scripts for all routers

   |- src                               HDL for all routers

   \- tb                                test bench files for all routers

  * doc                                 documents

  * lib                                 minimal Nangate 45nm cell lib

  * sdm                                 SDM/wormhole router design

   \- define.v                          HDL configuration file

   |- define.h                          test bench configuration

   |- sim                               simulation run dir

   |- src                               HDL

   |- syn                               synthesis run dir

    \- script                           synthesis script

   \- tb                                test bench

  * vc                                  VC router (ongoing)

How to run:

  * to synthesize a router

    1. set up your design compiler enviornment and your cell library.

    2. modify the "define.v" configuration file for the strcture your want.

       currently including:

         ENABLE_CLOS   use the 2-stage Clos switch instead of crossbar

         ENABLE_CRRD   use the CRRD dispatching algorithm for the Clos

         ENABLE_MRMA   use the multi-resource matching arbiter instead of MNMA

         ENABLE_CHANNEL_SLICING  use channel slicing

         ENABLE_LOOKAHEAD  use the lookahead pipelines

         ENABLE_EOF    router use eof bit to indicate end-of-frame

    3. modify the "compile.tcl" scription for the design parameters.

       currently including:

         VCN   number of virtual circuits

         DW    the data width of a single virtual circuit

         IPD   the depth of input buffers

         OPD   the depth of putput buffers

    4. if another cell lib is used, change "cell_lib.v" in common\src and other related

       files. (very likely you need to email me for further instructions :-) )

    5. modify the "tech.tcl" in common/script for your cell library.

    6. run the synthesis at [sdm/vc]/syn

       dc_shell -f script/compile.tcl

    7. the synthesized netlist is inside [sdm/vc]/syn/file/

  * to run post-synthesis simulation

    1. check the netlists in [sdm/vc]/syn/file/

    2. modify the testbench configuration "define.h" according to your requirements.

    3. make sure your NC-Simulator is installed alright (proper SystemC support).

    4. run the compilation at [sdm/vc]/sim

       compile.tcl

    5. run the simulation at [sdm/vc]/sim

       ncsim -tcl noctb

    6. the simulation output files are *.ana at [sdm/vc]/sim

       "throughput.ana":

         {simulation time in ps} TAB {throughput in bytes}

       "delay.ana":

         {simulation time in ps} TAB {avg. frame latency} TAB {avg. path setup delay}

For any questions and bug reports,

    please email to Wei Song from wsong83@gmail.com

Wei Song

01/06/2011