raspberry-pi-pcie-devices VS simdjson

Generally yes. M.2 wifi cards are just PCI-E (except for Intel CNVio). Jeff Geerling tried a bunch of different PCI-E cards with the Raspberry Pi 4 Compute Module which does expose the PCI-E interface: https://pipci.jeffgeerling.com/

We're also trying to preserve the utility of older cards by getting at least portions of the drivers working on alternate platforms (like arm64), so they can be repurposed for Plex/Jellyfin transcoding, retro gaming, GPU compute, etc.: https://github.com/geerlingguy/raspberry-pi-pcie-devices/iss...

The current answer is maybe: https://github.com/geerlingguy/raspberry-pi-pcie-devices/iss...

The PCIe implementation on the 5 is supposedly more complete/less broken than on the CM4, but so far the only person crazy/inspired enough to test hasn't gotten back to this card with their Pi 5 setup.

Just a note that if you're _serious_ about WiFi on the Raspberry Pi... you should use an external WiFi adapter—either PCIe or USB.

With the Compute Module 4, I've successfully tested a variety of adapters [1], from WiFi 6E to older mini PCIe and M.2 cards. There's even a board made for the purpose of multi-WiFi testing, the Seaberry [2].

The Raspberry Pi 5 works with all the PCIe WiFi chips I've tested (haven't had time to summarize testing on pipci database site yet, including a mt7921u-based WiFi 6E USB adapter (haven't written that up, but check out [3]).

[1] https://pipci.jeffgeerling.com/#network-cards-nics-and-wifi-...

[2] https://pipci.jeffgeerling.com/boards_cm/seaberry.html

[3] https://github.com/morrownr/USB-WiFi/issues/137#issuecomment...

https://pipci.jeffgeerling.com honestly I'd get a home server and run HA through docker, it's gotten me into home servers.

The simplest access you can get would be by using a CM board (as that has PCI Express available on its connectors) but driver issues galore exist. AMD have been more open the the "greenies" but the closest result I have seen is documented by Jeff Geerling

Are you familiar with a YouTuber named Jeff Geerling? He does some pretty far out stuff with pi’s like connecting video cards to them, etc. here’s a videoabout stuff you could do, I haven’t watched it myself. He’s got this website that has a list of accessories he’s tried with the pi. While I was looking for his channel I saw a ton of videos on YouTube for stuff to do with the pi. Curious to see what you end up doing… I guess I’m kinda hoping you do something that utilizes the full potential of the 4 😁

It's also supported by simdjson [0] (which has a lot of language bindings [1]):

> Multithreaded processing of gigantic Newline-Delimited JSON (ndjson) and related formats at 3.5 GB/s

[0] https://simdjson.org/

[0] https://github.com/simdjson/simdjson?tab=readme-ov-file#bind...

String parsing is negligible compared to the speed of the DOM which is glacially slow: https://news.ycombinator.com/item?id=38835920

Come on, people, make an effort to learn how insanely fast computers are, and how insanely inefficient our software is.

String parsing can be done at gigabytes per second: https://github.com/simdjson/simdjson If you think that is the slowest operation in the browser, please find some resources that talk about what is actually happening in the browser?

Thanks for all the detailed information! That answers a bunch of my questions and the implementation of strlen is nice.

The instruction I was thinking of is pshufb. An example ‘weird’ use can be found for detecting white space in simdjson: https://github.com/simdjson/simdjson/blob/24b44309fb52c3e2c5...

This works as follows:

1. Observe that each ascii whitespace character ends with a different nibble.

2. Make some vector of 16 bytes which has the white space character whose final nibble is the index of the byte, or some other character with a different final nibble from the byte (eg first element is space =0x20, next could be eg 0xff but not 0xf1 as that ends in the same nibble as index)

3. For each block where you want to find white space, compute pcmpeqb(pshufb(whitespace, input), input). The rules of pshufb mean (a) non-ascii (ie bit 7 set) characters go to 0 so will compare false, (b) other characters are replaced with an element of whitespace according to their last nibble so will compare equal only if they are that whitespace character.

I’m not sure how easy it would be to do such tricks with vgather.vv. In particular, the length of the input doesn’t matter (could be longer) but the length of white space must be 16 bytes. I’m not sure how the whole vlen stuff interacts with tricks like this where you (a) require certain fixed lengths and (b) may have different lengths for tables and input vectors. (and indeed there might just be better ways, eg you could imagine an operation with a 256-bit register where you permute some vector of bytes by sign-extending the nth bit of the 256-bit register into the result where the input byte is n).

Additionally, if you like low level stuff, check out libfmt (https://github.com/fmtlib/fmt) - not a big project, not difficult to understand. Or something like simdjson (https://github.com/simdjson/simdjson).

Everything you said is totally reasonable. I'm a big fan of napkin math and theoretical upper bounds on performance.

simdjson (https://github.com/simdjson/simdjson) claims to fully parse JSON on the order of 3 GB/sec. Which is faster than OP's Go whitespace parsing! These tests are running on different hardware so it's not apples-to-apples.

The phrase "cannot go faster than this" is just begging for a "well ackshully". Which I hate to do. But the fact that there is an existence proof of Problem A running faster in C++ SIMD than OP's Probably B scalar Go is quite interesting and worth calling out imho. But I admit it doesn't change the rest of the post.

I have same question as /u/JDRiverRun : how do you deal with JSON, do you parse json on Rust side or on Emacs side. I see that you are requiring json.el in your lspce.el, but I haven't looked through entire file carefully. If you parse on Rust side, do you use simdjson (there are at least two Rust bindings to it)? If yes, what are your impressions, experiences compared to more "standard" json library?