Out of curiosity how good are the open source tool...
# general
z
Out of curiosity how good are the open source tools at like mosfet level synthesis?
m
What is MOSFET-level synthesis?
z
Well like are there tools capable of optimizing how many mosfets are needed for a given circuit?
Or like do they do floorplanning well?
m
If you are talking about the digital design synthesis, then AFAIK it has nothing to do with the transistors (directly). What a synthesizer (e.g. Yosys) do is using Boolean Algebra to optimize your RTL code and using less logic gates (so less MOSFETs). Floorplanning is related to back-end process and AFAIK it doesn’t optimize the gates.
z
Right I know floorplanning doesn't optimize the gates, I just also wanted to know how good it was.
m
Please note the following quote from the OpenROAD project:
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The IDEA program targets no-human-in-loop (NHIL) design, with 24-hour turnaround time and zero loss of power-performance-area (PPA) design quality.
This might help you a lot to have a better understanding about OpenROAD target and the difference b/w this tool and something like ICC II. For more info check this out.
z
Thanks
m
No problem. Hope this would help.
z
I'm just reading Harris and Weste and they talk about transistor level optimization, so I was curious how good the open source solutions were if they existed
m
Would you mind point me to some references which describe the definition of transistor level optimizations? Are you talking about PPA optimization?
z
Like how you could make an adder using only Nand gates, but it's more efficient to not do that, similarly you can directly think about it on the transistor level.
m
IMHO this is a PPA (Power, Performance, Area) optimization question… As I said before, the main objective of the OpenROAD project is to let one person to do the whole back-end process in less than 24 hours. As a result unlike commercial tools (like ICC) you won’t have a lot of options to fully control the whole process and this will lead to less optimized PPA in comparison with commercial tools. On the other hand, using a commercial tool needs a huge amount of man hours and a lot of experts. This is a kind of trade off. However the OpenROAD team is working on this to achieve the ultimate goal of the project:
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no-human-in-loop (NHIL) design, with 24-hour turnaround time and zero loss of power-performance-area (PPA) design quality.
z
Gotcha, yeah that's fair.
m
Maybe other people could help you more so still wait for other answers…