[Gems-users] Confused about latency in PRINT_TOPOLOGY

[Hemayet Hossain <hossain@xxxxxxxxxxxxxxxx>]

Hi,
I am confused about the link latency printed. Can anyone please clarify 
how the number is to interpret correctly? I am trying to set a file 
specified network having 16 L1Cache controllers and  16 L2 cache 
controllers connected by a 4x4 mesh (each switch is connected with 1 
L1Cache and 1 L2Cache). The output wrt L1Cache-0 and portion of the 
network file is given here.
From what I understand latency for L1Cache0-->L1Cache1is correct as 
these two are connected through 2 intermediate switches (2 @ 1 per 
switch) and 3 links (9 @ 3 per links). And so for L1Cache0-->L1Cache2 is 
reasonable. If I apply same calculation then L1Cache0-->L1Cache3 should 
have 19 but it is showing 15 (only possible if torus assumed but that is 
not the case specified in network file).
I really appreciate your reply.
Thanks,
Hemayet

 L1Cache-0 Network Latencies
-------------------------------------------------
 L1Cache-0 -> L1Cache-1 net_lat: 11
 L1Cache-0 -> L1Cache-2 net_lat: 15
 L1Cache-0 -> L1Cache-3 net_lat: 15
 L1Cache-0 -> L1Cache-4 net_lat: 11
 L1Cache-0 -> L1Cache-5 net_lat: 15
 L1Cache-0 -> L1Cache-6 net_lat: 15
 L1Cache-0 -> L1Cache-7 net_lat: 15
 L1Cache-0 -> L1Cache-8 net_lat: 15
 L1Cache-0 -> L1Cache-9 net_lat: 15
 L1Cache-0 -> L1Cache-10 net_lat: 15
 L1Cache-0 -> L1Cache-11 net_lat: 15
 L1Cache-0 -> L1Cache-12 net_lat: 15
 L1Cache-0 -> L1Cache-13 net_lat: 15
 L1Cache-0 -> L1Cache-14 net_lat: 15
 L1Cache-0 -> L1Cache-15 net_lat: 15
 L1Cache-0 -> L2Cache-0 net_lat: 7
 L1Cache-0 -> L2Cache-1 net_lat: 11
 L1Cache-0 -> L2Cache-2 net_lat: 15
 L1Cache-0 -> L2Cache-3 net_lat: 15
 L1Cache-0 -> L2Cache-4 net_lat: 11
 L1Cache-0 -> L2Cache-5 net_lat: 15
 L1Cache-0 -> L2Cache-6 net_lat: 15
 L1Cache-0 -> L2Cache-7 net_lat: 15
 L1Cache-0 -> L2Cache-8 net_lat: 15
 L1Cache-0 -> L2Cache-9 net_lat: 15
 L1Cache-0 -> L2Cache-10 net_lat: 15
 L1Cache-0 -> L2Cache-11 net_lat: 15
 L1Cache-0 -> L2Cache-12 net_lat: 15
 L1Cache-0 -> L2Cache-13 net_lat: 15
 L1Cache-0 -> L2Cache-14 net_lat: 15
 L1Cache-0 -> L2Cache-15 net_lat: 15

Network File
----------------------------------------
ext_node:L1Cache:0 int_node:0 link_latency:3 bw_multiplier:16
ext_node:L2Cache:0 int_node:0 link_latency:3 bw_multiplier:16

ext_node:L1Cache:1 int_node:1 link_latency:3 bw_multiplier:16
ext_node:L2Cache:1 int_node:1 link_latency:3 bw_multiplier:16

ext_node:L1Cache:2 int_node:2 link_latency:3 bw_multiplier:16
ext_node:L2Cache:2 int_node:2 link_latency:3 bw_multiplier:16

ext_node:L1Cache:3 int_node:3 link_latency:3 bw_multiplier:16
ext_node:L2Cache:3 int_node:3 link_latency:3 bw_multiplier:16

ext_node:L1Cache:4 int_node:4 link_latency:3 bw_multiplier:16
ext_node:L2Cache:4 int_node:4 link_latency:3 bw_multiplier:16

ext_node:L1Cache:5 int_node:5 link_latency:3 bw_multiplier:16
ext_node:L2Cache:5 int_node:5 link_latency:3 bw_multiplier:16

ext_node:L1Cache:6 int_node:6 link_latency:3 bw_multiplier:16
ext_node:L2Cache:6 int_node:6 link_latency:3 bw_multiplier:16

ext_node:L1Cache:7 int_node:7 link_latency:3 bw_multiplier:16
ext_node:L2Cache:7 int_node:7 link_latency:3 bw_multiplier:16

ext_node:L1Cache:8 int_node:8 link_latency:3 bw_multiplier:16
ext_node:L2Cache:8 int_node:8 link_latency:3 bw_multiplier:16

ext_node:L1Cache:9 int_node:9 link_latency:3 bw_multiplier:16
ext_node:L2Cache:9 int_node:9 link_latency:3 bw_multiplier:16

ext_node:L1Cache:10 int_node:10 link_latency:3 bw_multiplier:16
ext_node:L2Cache:10 int_node:10 link_latency:3 bw_multiplier:16

ext_node:L1Cache:11 int_node:11 link_latency:3 bw_multiplier:16
ext_node:L2Cache:11 int_node:11 link_latency:3 bw_multiplier:16

ext_node:L1Cache:12 int_node:12 link_latency:3 bw_multiplier:16
ext_node:L2Cache:12 int_node:12 link_latency:3 bw_multiplier:16

ext_node:L1Cache:13 int_node:13 link_latency:3 bw_multiplier:16
ext_node:L2Cache:13 int_node:13 link_latency:3 bw_multiplier:16

ext_node:L1Cache:14 int_node:14 link_latency:3 bw_multiplier:16
ext_node:L2Cache:14 int_node:14 link_latency:3 bw_multiplier:16

ext_node:L1Cache:15 int_node:15 link_latency:3 bw_multiplier:16
ext_node:L2Cache:15 int_node:15 link_latency:3 bw_multiplier:16


int_node:0 int_node:1 link_latency:3 bw_multiplier:16
int_node:1 int_node:2 link_latency:3 bw_multiplier:16
int_node:2 int_node:3 link_latency:3 bw_multiplier:16

int_node:4 int_node:5 link_latency:3 bw_multiplier:16
int_node:5 int_node:6 link_latency:3 bw_multiplier:16
int_node:6 int_node:7 link_latency:3 bw_multiplier:16

int_node:8 int_node:9 link_latency:3 bw_multiplier:16
int_node:9 int_node:10 link_latency:3 bw_multiplier:16
int_node:10 int_node:11 link_latency:3 bw_multiplier:16

int_node:12 int_node:13 link_latency:3 bw_multiplier:16
int_node:13 int_node:14 link_latency:3 bw_multiplier:16
int_node:14 int_node:15 link_latency:3 bw_multiplier:16


int_node:0 int_node:4 link_latency:3 bw_multiplier:16
int_node:4 int_node:8 link_latency:3 bw_multiplier:16
int_node:8 int_node:12 link_latency:3 bw_multiplier:16

int_node:1 int_node:5 link_latency:3 bw_multiplier:16
int_node:5 int_node:9 link_latency:3 bw_multiplier:16
int_node:9 int_node:13 link_latency:3 bw_multiplier:16

int_node:2 int_node:6 link_latency:3 bw_multiplier:16
int_node:6 int_node:10 link_latency:3 bw_multiplier:16
int_node:10 int_node:14 link_latency:3 bw_multiplier:16

int_node:3 int_node:7 link_latency:3 bw_multiplier:16
int_node:7 int_node:11 link_latency:3 bw_multiplier:16
int_node:11 int_node:15 link_latency:3 bw_multiplier:16