third-party/OpenExSys_NoC
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

initial commit for open source NoC IP

Browse Source
This commit is contained in:
Zexin Fu
2023-11-26 14:59:34 +01:00
commit 6ba3d27334
122 changed files with 14907 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

99
doc/router_spec.md Normal file
View File

@@ -0,0 +1,99 @@
# Router Spec
# 1 Routing Algorithm
Use XY routing, the routing result is calculated one hop ahead, which is look-ahead routing
## 1.1 XY Routing
Flits firstly go through X axis, then go though Y axis:
```
1st phase: Assign next address
2nd phase: Define new Next-port
```
## 1.2 Look-ahead Routing
# 2 Input Port
## 2.1 Input VC
1. Use Fixed VC Assignment with Dynamic VC Allocation (FVADA) [paper](https://sites.pitt.edu/~juy9/papers/Yi-HPCA10.pdf) vc allocation mechanism. The input VCs are associated with the flits' output port.
2. XY routing, so some of the output port are not used in some input ports.
* VC in each input port:
| input port | input port id | vc id | assigned output port | output port id |
| ---------- | ------------- | ----- | -------------------- | -------------- |
| N | 0 | 0 | S | 1 |
| | | 1 | L | 4 |
| S | 1 | 0 | N | 0 |
| | | 1 | L | 4 |
| E | 2 | 0 | N | 0 |
| | | 1 | S | 1 |
| | | 2 | W | 3 |
| | | 3 | L | 4 |
| W | 3 | 0 | N | 0 |
| | | 1 | S | 1 |
| | | 2 | E | 2 |
| | | 3 | L | 4 |
| L | 4 | 0 | N | 0 |
| | | 1 | S | 1 |
| | | 2 | E | 2 |
| | | 3 | W | 3 |
# 3 Switch Allocation
Use two-stage input-port-first allocation.
## 3.1 Local allocation
Use round robin arbition. As XY routing, the local arbiters' input port number are not the same.
## 3.2 Global allocation
Use round robin arbition. As XY routing, the global arbiters' input port number are not the same.
* input output port mapping for each SA global arbiter:
| output port | global SA arbiter connected input ports | global SA arbiter connected input ports id | next hop input port |
| ----------- | --------------------------------------- | ------------------------------------------ | ------------------- |
| N | S | 1 | S |
| | E | 2 | |
| | W | 3 | |
| | L | 4 | |
| S | N | 0 | N |
| | E | 2 | |
| | W | 3 | |
| | L | 4 | |
| E | W | 3 | W |
| | L | 4 | |
| W | E | 2 | E |
| | L | 4 | |
| L | N | 0 | - |
| | S | 1 | |
| | E | 2 | |
| | W | 3 | |
# 4 QoS
## 4.1 Common QoS
No special vc, all vc head flits ranked by QoS value.
* no extra real-time vc;
* no bypass arbiter for real-time vc;
* all vc involve QoS value compare.
## 4.2 Common QoS + extra real-time vc QoS
Add special vc for highest priority flits, all vc head flits ranked by QoS value.
* have extra real-time vc;
* no bypass arbiter for real-time vc;
* the real-time vc always win the local sa, and the local sa rr point should not be updated
* the real-time vc join global sa as common QoS, as it has highest QoS value, it can beat flits with other QoS value;
* all vc involve QoS value compare.
## 4.3 extra real-time vc QoS + bypass switch allocation + no common QoS
Add special vc for highest priority flits, other vc head flits have no QoS support.
* have extra real-time vc;
* have bypass arbiter for real-time vc;
* non-highest-priority vc have no QoS support.
* the real-time vc bypass local sa, and override common rr arbiter's result;
* the real-time vc from all possible inport use a separate rr arbiter at per global sa, and override common rr arbiter's result;
It can have the same real-time support as 4.2, but may have better timing.