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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