Hey everyone, for learning and researching purposes I'm trying to build a
simple custom routing algorithm in gem5/garnet between only two routers.
And use the custom routing algorithm in simulation command
But always i'm getting "Segmentation fault"
The following diagram represents what I'm trying to simulate.
[image: TwoRoutersSimple.jpg]
The names of each router are"routers0", "routers1" respectively.
The following is the full simulation command I'm trying to execute
sudo build/NULL/gem5.debug configs/example/garnet_synth_traffic.py
--injectionrate=0.02 --synthetic=uniform_random --network=garnet
--num-cpus=2 --num-dirs=2 --topology=TRouters --sim-cycles=10000000
--routing-algorithm=2
My routing is very simple, and i have tried to learn from the Mesh_XY
routing and imitate it, and modified the following function "int RoutingUnit
::outportComputeCustom(RouteInfo route, int inport, PortDirection
inport_dirn)" in file *src/mem/ruby/network/garnet/RoutingUnit.cc*
The following is my custom routing function
int RoutingUnit::outportComputeCustom(RouteInfo route, int inport,
PortDirection inport_dirn) {
PortDirection outport_dirn = "Unknown";
if(route.dest_router == 0)
{
std::cout << "Destination Router: 0" << std::endl;
outport_dirn = "routers0";
}
else
{
std::cout << "Destination Router: 1" << std::endl;
outport_dirn = "routers1";
}
return m_outports_dirn2idx[outport_dirn];
}
And I have configured a python script that will create the network with all
nodes, internal links, external links, and routers.
Each time I tried to run the simulation the output was "Segmentation fault".
with some investigation into the code, i found that there are two built in
maps attached to each router, m_outports_dirn2idx and m_outports_idx2dirn
I iterated over the previous maps, and the following is the output for
*routers1 *
*Map from dir to index*
Local 1
routers0 0
routers1 2
*Map from index to dir*
0 Local
1 Local
2 routers1
If someone has some knowledge about garnet, I hope you can help me out !
Best Regards,
*Eng. Karim Soliman*
Teaching Assistant
Computer Engineering Department
Pharos University in Alexandria (P.U.A)
from m5.params import *
from m5.objects import *
from common import FileSystemConfig
from topologies.BaseTopology import SimpleTopology
class TRouters(SimpleTopology):
description = "Two Routers Simple topology"
def __init__(self, controllers):
self.nodes = controllers
def makeTopology(self, options, network, IntLink, ExtLink, Router):
nodes = self.nodes
num_routers = options.num_cpus
link_latency = options.link_latency
router_latency = options.router_latency
# External Code -- Ceating two routers only working in different two time dmains
# create the routers and configure the routers
routers = [
Router(router_id = i, _name="R_"+str(i), latency = router_latency)
for i in range(num_routers)
]
network.routers = routers
for router in routers:
print(f"Router [{router.router_id}]: {router._name}")
# get the count of the controls per router and the remainder controls
cntrls_per_router, remainder = divmod(len(nodes), num_routers)
network_nodes = []
remainder_nodes = []
for node_index in range(len(nodes)):
if node_index < (len(nodes) - remainder):
network_nodes.append(nodes[node_index])
else:
remainder_nodes.append(nodes[node_index])
# create the External Links and configure the links
# external links must be connected to nodes aka controllers
link_count = 0
ext_links = []
for (i, n) in enumerate(network_nodes):
cntrl_level, router_id = divmod(i, num_routers)
assert cntrl_level < cntrls_per_router
ext_links.append(ExtLink(
link_id = link_count,
ext_node = n,
int_node = routers[router_id],
latency = link_latency
))
link_count += 1
network.ext_links = ext_links
# create the Internal Links and configure the links
L0 = IntLink(
link_id = link_count,
latency = link_latency,
src_node = routers[0],
dst_node = routers[1],
src_outport = "routers0",
dst_inport = "routers1",
weight = 1
)
print(f"{routers[0]} --> {routers[1]}")
# update link_count for the next link_id
link_count += 1
L1 = IntLink(
link_id = link_count,
latency = link_latency,
src_node = routers[1],
dst_node = routers[0],
src_outport = "routers1",
dst_inport = "routers0",
weight = 1
)
print(f"{routers[1]} --> {routers[0]}")
# connect routers & internal links & external links to the routers
network.int_links = [L0, L1]
for router in network.routers:
print(f"Router [{router.router_id}]: {router._name}")
# DEBUG SOME OUTPUTS
print("==========HOLA==========")
print(f"# of cntrls_per_router = {cntrls_per_router}")
print(f"# of router_latency = {router_latency}")
print(f"# of link_latency = {link_latency}")
print(f"# of link_count = {link_count}")
print(f"# of routers = {len(routers)}")
print(f"# of nodes = {len(nodes)}")
print(f"# of internal links = {len(network.int_links)}")
print(f"# of external links = {len(ext_links)}\n")
def registerTopology(self, options):
for i in range(options.num_cpus):
FileSystemConfig.register_node(
[i], MemorySize(options.mem_size) // options.num_cpus, i
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