Page 227 - AWSAR 2.0

same signal. This scenario
can easily be visualized for a Network-on-Chip (NoC), which
is considered as a promising
interconnect structure for
many-core systems. The
simulations executed on an
8x8 baseline 2D-mesh NoC
show that the actual maximum
latency on the network is
16.2 times of ideal maximum
latency. This indicates that
packets in network routers get
stuck at different pipeline stages for multiple additional cycles than desired. This happens due to congestion in network. During NoC validation, packet states are captured and stored as traces for all the packets present inside the routers. Because of the fact that multiple packets do not change their state for
Mr. Sidhartha Rout || 203
several cycles, many redundant packet traces are generated for small snapshot intervals. Our proposed mechanism can distinguish these redundant traces and keep only one copy from each redundant group. As a result, one instance of all unique trace is collected and thus, the system observability is maintained with very less amount of trace generated. The RTE scheme is able to save
significant amount of trace buffer space by discarding the redundant traces.
The wireless capability given to the proposed mechanism further reduces the amount of trace generated and also speed up the trace transfer process.
We have proposed wireless enabled debug platform with augmented redundant trace elimination (RTE) mechanism that can optimally utilize the existing trace buffer space and can provide high trace transfer capability.
Fig. 2. Interconnect debug platform using wireless links. The framework is using distributed trace buffers. WI HUB represents the network node with wireless interface. Wireless communication is used for on-chip payload communication, and off-chip trace transfer.
From experiments, it is observed that the average life of packet in-flight reduces notably in a wireless NoC (WNoC) in comparison to wired NoC. This is because multi-hop long range packet communication can be replaced by one-hop wireless communication in a
WNoC. This leads to less trace generation for the same amount of payload transfer. So, use of RTE and wireless interface together reduce the amount of traces to a great extent. We also propose to replace the existing interface used for exporting traces to the external debugger