Performance of popular microcontroller boards running uLisp | Hacker News Reader

Performance of popular microcontroller boards running uLisp

ulisp.com

62 pointstosh16 comments

I don't think I will ever use Lisp but I love the way this site documents different examples with all kinds of hardware. I wish there were more sites like these for other microcontroller/SoC languages like lua, mPython, Arduino derived boards etc.

If you're wondering why the Teensy does so well (as I was), it's because the core is running at four times the clock rate of the nearest comparator.

It's also sporting a much more advanced ARM core[1], Cortex-M7, compared to most of the other ARM boards which had Cortex-M0(+) cores.

The M7 supports cache unlike the M0(+), and the processor used[2] has 64kB of it, split evenly into instruction and data cache. It also supports branch speculation which the M0(+) does not.

While the Teensy has 4.5x the clock frequency of the Pico 1, the Teensy is 8x faster.

Main outlier is the Pico 2 with a Cortex-M33, though still at a reduced clockspeed compared to the Teensy. From what I can see[3] it does not have cache for its on-board memory, "just" branch speculation like the M7.

[1]: https://en.wikipedia.org/wiki/ARM_Cortex-M

[2]: https://www.nxp.com/part/MIMXRT1062DVL6A

[3]: https://datasheets.raspberrypi.com/rp2350/rp2350-product-bri...

If you compare it to the only other board in the table with more than 300 MHz (and the only RISC-V) you can see that Teensy outperforms it by a margin even when the results are scaled by clock speed.

Of course it would only be a complete picture taking power consumption into consideration.

Good idea - I'll add a column to the tables giving the current consumption for each board.

Given that it seems one can overclock[1] the RP2350 to 600MHz, it would be interesting to compare it to the Teensy at same frequency.

[1]: https://forums.raspberrypi.com/viewtopic.php?t=375975

Also the M7 is a superscaler. It's not mentioned often, but if the task allows it, you can use what's essentially 1.5x the execution units of the smaller cores. It's not a complete 2x, but I'm sure it helps.

I understand the appeal from a hobby perspective, but is there any advantageous use cases where it would make sense to choose uLisp over other more common solutions for microcontroller software development?

I think it’s cool, and I’ve played with it a bit, but aside from using it as a fidget spinner to explore lisp, I’m wondering if there are applications for the language that would provide an edge in actual use.

Probably lower memory requirements compared to any other "not C or ASM" environment.

That could be interesting in some cases.

You can do basic Calculus with a single file used as a header.

A file? I’m not sure the context here ; we are talking about systems that in many cases do not have a file system?

On the Mini text-adventure sample, I wonder if porting Malyon from Emacs' Elisp could be feasible, at least to run v3 Zmachine games, small enough to be fastly interpreted even under a C64.

https://emacs.crys.site/interactive-fiction-malyon/

The Sudoku example ran as-is under Common Lisp, maybe it's the same under Emacs.

A libre v3 game to freely test it would be Calypso, among Tristam Island.

This example in ANS Forth (restricted) interpreters gave me nightmares because I was dancing with the stack back and forth. No pun intended. With Lisp, it's a piece of cake.

http://www.ulisp.com/show?1FHA

As far as I'm aware, the ESP32C3 is RISC-V - should it belong in the RISC-V table?

You're correct that the ESP32-C3 is based on a RISC-V processor, but it has more in common with the other ESP32 boards than it does with the boards supported by the RISC-V version of uLisp, so it made sense to support it with the ESP version of uLisp.

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