XBar.py (11604:b254396b7759) XBar.py (12341:6eebba99d117)
1# Copyright (c) 2012, 2015 ARM Limited
1# Copyright (c) 2012, 2015, 2017 ARM Limited
2# All rights reserved.
3#
4# The license below extends only to copyright in the software and shall
5# not be construed as granting a license to any other intellectual
6# property including but not limited to intellectual property relating
7# to a hardware implementation of the functionality of the software
8# licensed hereunder. You may use the software subject to the license
9# terms below provided that you ensure that this notice is replicated

--- 91 unchanged lines hidden (view full) ---

101 snoop_filter = Param.SnoopFilter(NULL, "Selected snoop filter")
102
103 # Determine how this crossbar handles packets where caches have
104 # already committed to responding, by establishing if the crossbar
105 # is the point of coherency or not.
106 point_of_coherency = Param.Bool(False, "Consider this crossbar the " \
107 "point of coherency")
108
2# All rights reserved.
3#
4# The license below extends only to copyright in the software and shall
5# not be construed as granting a license to any other intellectual
6# property including but not limited to intellectual property relating
7# to a hardware implementation of the functionality of the software
8# licensed hereunder. You may use the software subject to the license
9# terms below provided that you ensure that this notice is replicated

--- 91 unchanged lines hidden (view full) ---

101 snoop_filter = Param.SnoopFilter(NULL, "Selected snoop filter")
102
103 # Determine how this crossbar handles packets where caches have
104 # already committed to responding, by establishing if the crossbar
105 # is the point of coherency or not.
106 point_of_coherency = Param.Bool(False, "Consider this crossbar the " \
107 "point of coherency")
108
109 # Specify whether this crossbar is the point of unification.
110 point_of_unification = Param.Bool(False, "Consider this crossbar the " \
111 "point of unification")
112
109 system = Param.System(Parent.any, "System that the crossbar belongs to.")
110
111class SnoopFilter(SimObject):
112 type = 'SnoopFilter'
113 cxx_header = "mem/snoop_filter.hh"
114
115 # Lookup latency of the snoop filter, added to requests that pass
116 # through a coherent crossbar.

--- 17 unchanged lines hidden (view full) ---

134 response_latency = 1
135 snoop_response_latency = 1
136
137 # Use a snoop-filter by default, and set the latency to zero as
138 # the lookup is assumed to overlap with the frontend latency of
139 # the crossbar
140 snoop_filter = SnoopFilter(lookup_latency = 0)
141
113 system = Param.System(Parent.any, "System that the crossbar belongs to.")
114
115class SnoopFilter(SimObject):
116 type = 'SnoopFilter'
117 cxx_header = "mem/snoop_filter.hh"
118
119 # Lookup latency of the snoop filter, added to requests that pass
120 # through a coherent crossbar.

--- 17 unchanged lines hidden (view full) ---

138 response_latency = 1
139 snoop_response_latency = 1
140
141 # Use a snoop-filter by default, and set the latency to zero as
142 # the lookup is assumed to overlap with the frontend latency of
143 # the crossbar
144 snoop_filter = SnoopFilter(lookup_latency = 0)
145
146 # This specialisation of the coherent crossbar is to be considered
147 # the point of unification, it connects the dcache and the icache
148 # to the first level of unified cache.
149 point_of_unification = True
150
142# One of the key coherent crossbar instances is the system
143# interconnect, tying together the CPU clusters, GPUs, and any I/O
144# coherent masters, and DRAM controllers.
145class SystemXBar(CoherentXBar):
146 # 128-bit crossbar by default
147 width = 16
148
149 # A handful pipeline stages for each portion of the latency

--- 6 unchanged lines hidden (view full) ---

156 # Use a snoop-filter by default
157 snoop_filter = SnoopFilter(lookup_latency = 1)
158
159 # This specialisation of the coherent crossbar is to be considered
160 # the point of coherency, as there are no (coherent) downstream
161 # caches.
162 point_of_coherency = True
163
151# One of the key coherent crossbar instances is the system
152# interconnect, tying together the CPU clusters, GPUs, and any I/O
153# coherent masters, and DRAM controllers.
154class SystemXBar(CoherentXBar):
155 # 128-bit crossbar by default
156 width = 16
157
158 # A handful pipeline stages for each portion of the latency

--- 6 unchanged lines hidden (view full) ---

165 # Use a snoop-filter by default
166 snoop_filter = SnoopFilter(lookup_latency = 1)
167
168 # This specialisation of the coherent crossbar is to be considered
169 # the point of coherency, as there are no (coherent) downstream
170 # caches.
171 point_of_coherency = True
172
173 # This specialisation of the coherent crossbar is to be considered
174 # the point of unification, it connects the dcache and the icache
175 # to the first level of unified cache. This is needed for systems
176 # without caches where the SystemXBar is also the point of
177 # unification.
178 point_of_unification = True
179
164# In addition to the system interconnect, we typically also have one
165# or more on-chip I/O crossbars. Note that at some point we might want
166# to also define an off-chip I/O crossbar such as PCIe.
167class IOXBar(NoncoherentXBar):
168 # 128-bit crossbar by default
169 width = 16
170
171 # Assume a simpler datapath than a coherent crossbar, incuring
172 # less pipeline stages for decision making and forwarding of
173 # requests.
174 frontend_latency = 2
175 forward_latency = 1
176 response_latency = 2
180# In addition to the system interconnect, we typically also have one
181# or more on-chip I/O crossbars. Note that at some point we might want
182# to also define an off-chip I/O crossbar such as PCIe.
183class IOXBar(NoncoherentXBar):
184 # 128-bit crossbar by default
185 width = 16
186
187 # Assume a simpler datapath than a coherent crossbar, incuring
188 # less pipeline stages for decision making and forwarding of
189 # requests.
190 frontend_latency = 2
191 forward_latency = 1
192 response_latency = 2