Mesh_westfirst.py revision 13731:67cd980cb20f 
1# Copyright (c) 2010 Advanced Micro Devices, Inc.
2#               2016 Georgia Institute of Technology
3# All rights reserved.
4#
5# Redistribution and use in source and binary forms, with or without
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8# notice, this list of conditions and the following disclaimer;
9# redistributions in binary form must reproduce the above copyright
10# notice, this list of conditions and the following disclaimer in the
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12# neither the name of the copyright holders nor the names of its
13# contributors may be used to endorse or promote products derived from
14# this software without specific prior written permission.
15#
16# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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25# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27#
28# Authors: Brad Beckmann
29#          Tushar Krishna
30
31from m5.params import *
32from m5.objects import *
33
34from BaseTopology import SimpleTopology
35
36# Creates a generic Mesh assuming an equal number of cache
37# and directory controllers.
38# West-first routing is enforced (using link weights)
39# to guarantee deadlock freedom.
40# The network randomly chooses between links with the same
41# weight for messages within unordered virtual networks.
42# Within ordered virtual networks, a fixed link direction
43# is always chosen based on which appears first inside the
44# routing table.
45
46class Mesh_westfirst(SimpleTopology):
47    description='Mesh_westfirst'
48
49    def __init__(self, controllers):
50        self.nodes = controllers
51
52    # Makes a generic mesh
53    # assuming an equal number of cache and directory cntrls
54
55    def makeTopology(self, options, network, IntLink, ExtLink, Router):
56        nodes = self.nodes
57
58        num_routers = options.num_cpus
59        num_rows = options.mesh_rows
60
61        # default values for link latency and router latency.
62        # Can be over-ridden on a per link/router basis
63        link_latency = options.link_latency # used by simple and garnet
64        router_latency = options.router_latency # only used by garnet
65
66        # There must be an evenly divisible number of cntrls to routers
67        # Also, obviously the number or rows must be <= the number of routers
68        cntrls_per_router, remainder = divmod(len(nodes), num_routers)
69        assert(num_rows > 0 and num_rows <= num_routers)
70        num_columns = int(num_routers / num_rows)
71        assert(num_columns * num_rows == num_routers)
72
73        # Create the routers in the mesh
74        routers = [Router(router_id=i, latency=router_latency) \
75            for i in range(num_routers)]
76        network.routers = routers
77
78        # link counter to set unique link ids
79        link_count = 0
80
81        # Add all but the remainder nodes to the list of nodes to be uniformly
82        # distributed across the network.
83        network_nodes = []
84        remainder_nodes = []
85        for node_index in range(len(nodes)):
86            if node_index < (len(nodes) - remainder):
87                network_nodes.append(nodes[node_index])
88            else:
89                remainder_nodes.append(nodes[node_index])
90
91        # Connect each node to the appropriate router
92        ext_links = []
93        for (i, n) in enumerate(network_nodes):
94            cntrl_level, router_id = divmod(i, num_routers)
95            assert(cntrl_level < cntrls_per_router)
96            ext_links.append(ExtLink(link_id=link_count, ext_node=n,
97                                    int_node=routers[router_id],
98                                    latency = link_latency))
99            link_count += 1
100
101        # Connect the remainding nodes to router 0.  These should only be
102        # DMA nodes.
103        for (i, node) in enumerate(remainder_nodes):
104            assert(node.type == 'DMA_Controller')
105            assert(i < remainder)
106            ext_links.append(ExtLink(link_id=link_count, ext_node=node,
107                                    int_node=routers[0],
108                                    latency = link_latency))
109            link_count += 1
110
111        network.ext_links = ext_links
112
113        # Create the mesh links.
114        int_links = []
115
116        # East output to West input links (weight = 2)
117        for row in range(num_rows):
118            for col in range(num_columns):
119                if (col + 1 < num_columns):
120                    east_out = col + (row * num_columns)
121                    west_in = (col + 1) + (row * num_columns)
122                    int_links.append(IntLink(link_id=link_count,
123                                             src_node=routers[east_out],
124                                             dst_node=routers[west_in],
125                                             latency = link_latency,
126                                             weight=2))
127                    link_count += 1
128
129        # West output to East input links (weight = 1)
130        for row in range(num_rows):
131            for col in range(num_columns):
132                if (col + 1 < num_columns):
133                    east_in = col + (row * num_columns)
134                    west_out = (col + 1) + (row * num_columns)
135                    int_links.append(IntLink(link_id=link_count,
136                                             src_node=routers[west_out],
137                                             dst_node=routers[east_in],
138                                             latency = link_latency,
139                                             weight=1))
140                    link_count += 1
141
142
143        # North output to South input links (weight = 2)
144        for col in range(num_columns):
145            for row in range(num_rows):
146                if (row + 1 < num_rows):
147                    north_out = col + (row * num_columns)
148                    south_in = col + ((row + 1) * num_columns)
149                    int_links.append(IntLink(link_id=link_count,
150                                             src_node=routers[north_out],
151                                             dst_node=routers[south_in],
152                                             latency = link_latency,
153                                             weight=2))
154                    link_count += 1
155
156        # South output to North input links (weight = 2)
157        for col in range(num_columns):
158            for row in range(num_rows):
159                if (row + 1 < num_rows):
160                    north_in = col + (row * num_columns)
161                    south_out = col + ((row + 1) * num_columns)
162                    int_links.append(IntLink(link_id=link_count,
163                                             src_node=routers[south_out],
164                                             dst_node=routers[north_in],
165                                             latency = link_latency,
166                                             weight=2))
167                    link_count += 1
168
169
170        network.int_links = int_links
171