[Gems-users] latency parameters in MOESI_SMP_directory protocol

[Edward Lee <edwl202@xxxxxxxxx>]

Hi,

I have couple of questions about the latency parameters in RUBY. I am using MOESI_SMP_directory protocol with GEMS 2.1 to simulate a 16-core CMP with private caches. I am a little confused about the latency calculation for directory. I am also using GARNET with 4x4 mesh with:

processors:16
procs_per_chip:1
L2banks:16
memories:16

ext_node:L1Cache:0 int_node:0 link_latency:1
...

ext_node:Directory:0 int_node:0 link_latency:10
...

int_node:0 int_node:1 link_latency:20 link_weight:1
...

Here the directory latency is set to 10 cycles and DIRECTORY_LATENCY parameter in rubyconfig.defaults is set to 80. So, what would be the actual directory latency observed here from core0 to directory0? Also, are directories stored in the main memory?

Thanks in advance for any insights,

Ed