Hi Tushar,
I am trying to create a different topology, similar to mesh but
it only has 1 director controller node which will be connected to
center node. For this, I am modifying the MeshDirCorners.py file
line 66 --
assert(len(dir_nodes) == 1) // changed from 4 to 1
and line 85
# Connect the dir nodes to the corners.
ext_links.append(ExtLink(link_id=link_count,
ext_node=dir_nodes[0],
int_node=mesh.routers[num_routers/2]))
link_count += 1
but, I get the following error:
Error: could not create topology MeshDirCorners
Traceback (most recent call last):
File "<string>", line 1, in <module>
File
"/home/tejasi/Gem5/gem5-c226cd1e5e5e/src/python/m5/main.py", line
356, in main
exec filecode in scope
File "configs/example/ruby_network_test.py", line 108, in <module>
Ruby.create_system(options, system)
File
"/home/tejasi/Gem5/gem5-c226cd1e5e5e/configs/ruby/Ruby.py", line
109, in create_system
% options.topology)
File "<string>", line 1, in <module>
File
"/home/tejasi/Gem5/gem5-c226cd1e5e5e/src/mem/ruby/network/topologies/MeshDirCorners.py",
line 66, in makeTopology
assert(len(dir_nodes) == 1)
AssertionError
I am not sure why is this error? Also, how does it know the node
type in line 48? Could you please guide me on this?
On Sat, Nov 19, 2011 at 11:52 PM, Tushar Krishna
<[email protected] <mailto:[email protected]>> wrote:
Hi Tejasi,
All routers are identical. Each router connects either to
another router, and to one or more controllers. In a mesh
topology, router 0 connects to two neighboring routers (to
its east and north), an L1 controller, a directory/memory
controller and a DMA controller.
No a DMA controller is not same as a memory controller.
src/mem/ruby/system defines some of the controllers while
some are generated per protocol.
Hmm all routers inherit from the same base class BasicRouter
so are identical ... You could add different functionality
for some of the routers by using the router's m_id as a
conditional ... ?
Routing Table entries:
Look at src/mem/ruby/network/Topology.cc
The createLinks function calculates shortest distance between
nodes and passes this information to makeLinks which in turn
calls the makeInLink, makeOutLink and makeInternalLink
functions in GarnetNetwork_d.cc which then calls each router
and populates its routing tables.
cheers,
Tushar
On 11/19/2011 10:21 PM, tejasi pimpalkhute wrote:
Hi Tushar,
Thanks for your reply. Can you please tell me if router[0]
which is connected to DMA_controller(is this same as memory
controller?), has any different structure or functionality
than other routers? If yes, could you please let me know
which file has the code for this? If no, could you please
let me know if we can implement a different functionality
for just one router?
Also, regarding routing destinations, can you please tell me
where does the routing_table_entry variable in
routing_unit.cc gets its value from?
I am unable to figure these things out by looking at the
code and hence stuck at one point.
Hope to hear from you soon.
On Thu, Oct 27, 2011 at 9:11 PM, Tushar Krishna
<[email protected] <mailto:[email protected]>> wrote:
Hi Tejasi,
In general there is *no fixed rule* for these, and
depends on the coherence protocol.
For most protocols currently in gem5, each "Directory"
Controller implies both a Directory (i.e. state) and a
Memory Controller.
The memory controller models the delay to main memory.
We don't define and connect a memory module separately
as far as I know.
The number of directories is an independent parameter
defined from command line (--num-dirs).
If you take a look at configs/ruby/MOESI_CMP_directory.py,
you can see that it creates L1 controllers, L2
controllers and Directory Controllers (in which it
creates both a DirectoryMemory => state, and a memory
controller).
Now when the directory receives a request that is not
currently on-chip (indicated by directory state), it
sends the request to the memory controller which models
memory delay for reads/writes etc ... [done in the
protocol's .sm file].
In terms of connections, all controllers (L1, L2 and
Directory) can be connected in any manner.
We provide two mesh topologies: Mesh.py and
MeshDirCorners.py.
Both topologies create a Mesh with the number of routers
= number of cpus (=number of L1s).
Mesh.py assumes equal number of all controllers (L1, L2
and directory), and connects one L1, one L2 (if it
exists) and one directory to each network router.
MeshDirCorners.py assumes 4 directories and connects
them at each corner.
All DMA controllers are just connected to router 0
(arbitrary decision) I think.
You can design your own topology too using the given
ones as reference.
You just need to add a .py file of your topology in the
topologies folder, and also add it in
src/mem/ruby/network/topologies/SConscript
Hope this helps,
Tushar
On 10/27/2011 4:09 PM, tejasi pimpalkhute wrote:
Hi,
I was looking into the code file Mesh.py in Topology
folder and the online documentation for it says that
every node has L1,L2 cache and directories connected to
it. As I had read somewhere, in Gem5, directory
controller and memory controller are same, could you
please let me know if Directory connected to each node
is same as main memory? Also, it seems that DMA
controller is attached to only remainder nodes as per
the code. So, it is a little bit confusing. Could you
please elaborate the connections of nodes to memory
controller and main memory.
Thanks!
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Thanks and Regards,
Tejasi
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Thanks and Regards,
Tejasi
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