[libre-riscv-dev] Scoreboard vs Tomasulo

Yehowshua yimmanuel3 at gatech.edu
Sat May 16 15:04:52 BST 2020

This website gives an excellent comparison

https://www.cs.umd.edu/~meesh/cmsc411/website/projects/dynamic/intro.html <https://www.cs.umd.edu/~meesh/cmsc411/website/projects/dynamic/intro.html>

In general, it sits that Tomasulo is a distributed scoreboard.

The biggest drawback of Tomasulo is the central data bus as the messaging scheme. One could use a mesh NOC between functional units.

Given that we have well over 15 functional units, I would have thought a distributed scoreboard instead of a centralized one makes more sense.

Of course, I have no numbers to back this up. But these are just some thoughts.

I know we’re using a ring/circular buffer for messaging at the moment.
Given that we have hard deadlines and limited resources, we can stick with this. But these are questions I do wonder about the answer to. I wonder if there are any papers where this has been explored at sufficient depth to draw conclusions.


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