gem5/configs/topologies/MeshDirCorners_XY.py

# Copyright (c) 2010 Advanced Micro Devices, Inc.
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# Authors: Brad Beckmann

from m5.params import *
from m5.objects import *

from BaseTopology import SimpleTopology

# Creates a Mesh topology with 4 directories, one at each corner.
# One L1 (and L2, depending on the protocol) are connected to each router.
# XY routing is enforced (using link weights) to guarantee deadlock freedom.

class MeshDirCorners_XY(SimpleTopology):
    description='MeshDirCorners_XY'

    def __init__(self, controllers):
        self.nodes = controllers

    def makeTopology(self, options, network, IntLink, ExtLink, Router):
        nodes = self.nodes

        num_routers = options.num_cpus
        num_rows = options.mesh_rows

        # First determine which nodes are cache cntrls vs. dirs vs. dma
        cache_nodes = []
        dir_nodes = []
        dma_nodes = []
        for node in nodes:
            if node.type == 'L1Cache_Controller' or \
            node.type == 'L2Cache_Controller':
                cache_nodes.append(node)
            elif node.type == 'Directory_Controller':
                dir_nodes.append(node)
            elif node.type == 'DMA_Controller':
                dma_nodes.append(node)

        # Obviously the number or rows must be <= the number of routers
        # and evenly divisible.  Also the number of caches must be a
        # multiple of the number of routers and the number of directories
        # must be four.
        assert(num_rows <= num_routers)
        num_columns = int(num_routers / num_rows)
        assert(num_columns * num_rows == num_routers)
        caches_per_router, remainder = divmod(len(cache_nodes), num_routers)
        assert(remainder == 0)
        assert(len(dir_nodes) == 4)

        # Create the routers in the mesh
        routers = [Router(router_id=i) for i in range(num_routers)]
        network.routers = routers

        # link counter to set unique link ids
        link_count = 0

        # Connect each cache controller to the appropriate router
        ext_links = []
        for (i, n) in enumerate(cache_nodes):
            cntrl_level, router_id = divmod(i, num_routers)
            assert(cntrl_level < caches_per_router)
            ext_links.append(ExtLink(link_id=link_count, ext_node=n,
                                    int_node=routers[router_id]))
            link_count += 1

        # Connect the dir nodes to the corners.
        ext_links.append(ExtLink(link_id=link_count, ext_node=dir_nodes[0],
                                int_node=routers[0]))
        link_count += 1
        ext_links.append(ExtLink(link_id=link_count, ext_node=dir_nodes[1],
                                int_node=routers[num_columns - 1]))
        link_count += 1
        ext_links.append(ExtLink(link_id=link_count, ext_node=dir_nodes[2],
                                int_node=routers[num_routers - num_columns]))
        link_count += 1
        ext_links.append(ExtLink(link_id=link_count, ext_node=dir_nodes[3],
                                int_node=routers[num_routers - 1]))
        link_count += 1

        # Connect the dma nodes to router 0.  These should only be DMA nodes.
        for (i, node) in enumerate(dma_nodes):
            assert(node.type == 'DMA_Controller')
            ext_links.append(ExtLink(link_id=link_count, ext_node=node,
                                     int_node=routers[0]))

        network.ext_links = ext_links

        # Create the mesh links.
        int_links = []

        # East output to West input links (weight = 1)
        for row in xrange(num_rows):
            for col in xrange(num_columns):
                if (col + 1 < num_columns):
                    east_out = col + (row * num_columns)
                    west_in = (col + 1) + (row * num_columns)
                    int_links.append(IntLink(link_id=link_count,
                                             src_node=routers[east_out],
                                             dst_node=routers[west_in],
                                             weight=1))
                    link_count += 1

        # West output to East input links (weight = 1)
        for row in xrange(num_rows):
            for col in xrange(num_columns):
                if (col + 1 < num_columns):
                    east_in = col + (row * num_columns)
                    west_out = (col + 1) + (row * num_columns)
                    int_links.append(IntLink(link_id=link_count,
                                             src_node=routers[west_out],
                                             dst_node=routers[east_in],
                                             weight=1))
                    link_count += 1

        # North output to South input links (weight = 2)
        for col in xrange(num_columns):
            for row in xrange(num_rows):
                if (row + 1 < num_rows):
                    north_out = col + (row * num_columns)
                    south_in = col + ((row + 1) * num_columns)
                    int_links.append(IntLink(link_id=link_count,
                                             src_node=routers[north_out],
                                             dst_node=routers[south_in],
                                             weight=2))
                    link_count += 1

        # South output to North input links (weight = 2)
        for col in xrange(num_columns):
            for row in xrange(num_rows):
                if (row + 1 < num_rows):
                    north_in = col + (row * num_columns)
                    south_out = col + ((row + 1) * num_columns)
                    int_links.append(IntLink(link_id=link_count,
                                             src_node=routers[south_out],
                                             dst_node=routers[north_in],
                                             weight=2))
                    link_count += 1


        network.int_links = int_links