[Gems-users] Garnet Network parameters

[Edward Lee <edwl202@xxxxxxxxx>]

Hi all,

I would like to verify the meaning of some simulation parameters to
come up with realistic network parameters.
I am running a 2GHz serengeti machine with 16 processors using
MOESI_SMP_directory protocol to simulate a 16-core CMP with private
caches.

Here are some configuration values:

SIMICS_RUBY_MULTIPLIER: 4 --> does this mean Ruby clock is 2GHz/4 = 0.5GHz?

network is 4x4 MESH via GARNET
g_FLIT_SIZE: 16

a snapshot of network parameters:

....

ext_node:L1Cache:0 int_node:0 link_latency:1
ext_node:Directory:0 int_node:0 link_latency:4
int_node:0 int_node:1 link_latency:8 link_weight:1

...

So, since FLIT_SIZE refers to bytes/cycle and it is suggested to tune
the latencies for lower bandwidths. Would it be accurate to make the
following assumtions?

16 bytes/cycle * 0.5 Ghz / link_latency = link_bandwidth

Accordingly,

bandwidth to caches 8GB/s, bandwidth to memory/directory 2 GB/s,
bandwidth between cores is 1GB/s

Thanks for any input in advance,

Ed