Don't forget the 128 bit vector ISA with 32 registers, supporting up to 64 bit int and FP, and with LMUL=8 you can process 1024 bits with a single instruction (at 3 cycles per 128 bits for most operations). Fully supported by GCC and CLANG (xTHeadVector) and compatible with RVV 1.0 with just a command line switch if you use the C intrinsic functions. (a lot of code working on 8 bit elements is binary compatible with RVV 1.0 too e.g. typical memcpy(), memset(), memcmp(), strlen(), strcpy(), strcmp())

When I bought my 64 MB Duo they were $3!

Then for a long time they were $5 for the 64 MB, $7 for the 256 MB, and $10 for the 512 MB.

Sadly, like everything else, they've gone up considerably this year.

https://arace.tech/products/milk-v-duo

https://arace.tech/products/milkv-duo-s

You can buy sub-$0.50 microcontrollers. But even at $5, I don't know why you'd want to run models on them, it's an environment constrained to the point of being useless for this task.

And I hope it stays that way, I don't want MCU shortages...

One of the things I have been wanting to try for a while now is something like this with a layer per MCU. I have some crazy ideas with RP2350's talking to each other with dedicated lines fed by PIO going through a combination of interpolators and dual multiply instructions.

PSRAM, Flash, and even SD cards may not have the best bandwidth individually, but they can reach quite impressive rates when you have a shitton of them running all at the same time.

The large scale dedicated hardware systems will still have the edge for performance per watt, but the low entry level and slow incline does make these things quite appealing.

Someone did this exact thing recently, but running GLM-5.2 with something like 16GB of DRAM, a standard desktop CPU and nVME SSD.

I think they got something like 10 _seconds per token_ (not tokens per second).

EDIT: it was 25GB of ram and up to 20 seconds per token! https://github.com/JustVugg/colibri

My guess is because the ESP32's flash is only ~1/4 the bandwidth of the internal SRAM. If you do this on a more powerful system not only is the gap much wider but you also have much more compute you need to keep fed with bandwidth to be efficient.

If you want to do this at the $1 price point, you can on RP2350, albeit with some limitations. In particular, it maxes out at full speed (12Mbps). The trick is to use the on-chip USB peripheral for one, and connect the other to GPIO pins backed by PIO.

This works today with tinyusb and pico-pio-usb, but I'm also playing with a Rust port which I'm hoping will have higher performance.